Economic Assessment of Building Adaptation to Climate Change: A Systematic Review of Cost Evaluation Methods

Highlights

What are the main findings?

• The paper provides the first systematic literature review on cost-based methods for assessing climate adaptation in buildings, covering 38 peer-reviewed studies from 2019–2024.
• It identifies Cost–Benefit Analysis (CBA) as the most frequently applied approach, with Life-Cycle Costing (LCC) and emerging methods such as Multi-Criteria Decision-Making (MCDM) frameworks gaining attention.
• A clear implementation gap is highlighted: most studies remain hazard-specific (mainly flood risk), ex-post, and disconnected from building design, renovation, and investment processes.

What are the implications of the main findings?

• Stakeholders need integrated, user-friendly tools to compare adaptation costs versus inaction, including co-benefits.
• Policymakers should embed systemic risk and cost analysis into regulations, procurement, and financing schemes.
• Future research should advance multi-hazard, economically grounded methodologies aligned with EU adaptation and sustainability policies and practice.

Abstract

Climate change is intensifying the frequency and severity of extreme weather events, threatening the resilience of buildings and urban infrastructure. While technical solutions for climate adaptation in buildings are well documented, their economic viability remains a critical, yet underexplored, dimension of decision-making. This novel systematic review analyzes publications with an exclusive focus on climate adaptation strategies for buildings using cost-based evaluation methods. This review categorises the literature into three methodological clusters: Cost–Benefit Analysis (CBA), Life Cycle Costing (LCC), and alternative methods including artificial intelligence, simulation, and multi-criteria approaches. CBA emerges as the most frequently used and versatile tool, often applied to evaluate micro-scale flood protection and nature-based solutions. LCC is valuable for assessing long-term investment efficiency, particularly in retrofit strategies targeting energy and thermal performance. Advanced methods, such as genetic algorithms and AI-driven models, are gaining traction but face challenges in data availability and transparency. Most studies focus on residential buildings and flood-related hazards, with a growing interest in heatwaves, wildfires, and compound risk scenarios. Despite methodological advancements, challenges persist—including uncertainties in climate projections, valuation of non-market benefits, and limited cost data. This review highlights the need for integrated frameworks that combine economic, environmental, and social metrics, and emphasises the importance of stakeholder-inclusive, context-sensitive decision-making. Ultimately, aligning building adaptation with financial feasibility and long-term sustainability is achievable through improved data quality, flexible methodologies, and supportive policy instruments.

1. Introduction

1.1. Context and Importance

The escalating impacts of climate change—manifested through increased frequency and intensity of extreme weather events such as heatwaves, floods, and storms—pose significant challenges to the built environment [1,2]. Buildings, as long-lived and capital-intensive assets, are particularly vulnerable, necessitating adaptation measures to enhance their resilience and ensure the safety, health, and comfort of occupants.

Adaptation strategies for buildings encompass a wide range of interventions, including passive design enhancements (e.g., insulation, shading) [3], active system upgrades (e.g., high-efficiency HVAC), and nature-based solutions (e.g., green roofs, rain gardens) [4]. While studies highlight the technical effectiveness of these measures in mitigating climate-related risks, the economic viability of such interventions remains a crucial, and often underexplored, dimension of decision-making [5,6].

Evaluating the costs and benefits of climate adaptation and hazard mitigation measures is essential for informed decision-making. Climate resilience analysis accounts for the expenses involved in implementing adaptation projects, including the total investment costs (i.e., materials and labour), as described by Seddiki and Bennadji [7], while the benefits arise from decreased expected damage caused by weather-related events. These insights can be translated into quantitative indicators for the various adaptation options, enabling comparison and guiding project selection [8]. As the risk of extreme weather events intensifies with climate change [9], assessing related costs is crucial for the long-term planning of buildings and infrastructure projects [10]. Cost–Benefit Analysis (CBA) has emerged as a key analytical tool in this context [11] enabling policymakers and stakeholders to systematically evaluate adaptation and retrofitting options by comparing the anticipated long-term benefits—such as reduced damage, energy savings, and health improvements—against the upfront and ongoing costs [12]. However, applying CBA to climate adaptation in buildings presents several methodological and practical challenges [13], including uncertainty in future climate projections, valuation of non-market benefits, discounting future impacts, and data limitations [14].

In certain contexts, probabilistic loss assessment methodologies can support the optimisation of building design. For example, Braik et al. [15] applied a multi-objective optimisation framework that accounted for multi-hazard risks, integrated both direct and indirect losses into the cost assessment, and employed probabilistic hazard analysis across different time horizons to evaluate alternative retrofit strategies for residential buildings in hurricane-prone communities.

Moreover, more broadly, economic assessments can significantly influence prioritisation and resource allocation for adaptation projects. Underestimating long-term or indirect benefits may lead to the exclusion of solutions that could otherwise deliver substantial resilience gains [16]. Conversely, comprehensive cost analysis can support more informed, transparent, and equitable decision-making processes that align with climate-resilient development goals.

1.2. Linking Building Adaptation Economics to Smart Cities

Economical and multi-criteria approaches in digital urban platforms provide a structured way to connect adaptation strategies with decarbonisation pathways and smart city planning tools. Such integration ensures that climate adaptation measures are evaluated not only in terms of risk and vulnerability reduction but also through their contributions to energy efficiency, carbon neutrality, and sustainability objectives [17]. In this way, adaptation solutions become part of a broader governance framework that supports evidence-based investment decisions and ensures alignment with the goals of the green transition.

A critical need remains for more precise and comprehensive measurement tools and cost analyses—geographically balanced and methodologically advanced—to assess the economic returns of climate adaptation and smart city initiatives, thereby supporting investment prioritisation and maximising their recognised economic and environmental benefits [18].

The capacity of cities to remain resilient is closely tied to their level of smartness, with evidence at the European scale showing that smart solutions account for the majority of resilience outcomes [19]. Interaction between technology and nature can be significantly improved when a Smart City approach actively promotes the integration of climate strategies. Smart Cities, particularly when evolving into ‘Smart Sustainable Cities’ with integrated climate strategies and citizen involvement, hold significant potential as a solution to climate change adaptation, despite the short-term economic challenges of such initiatives [20].

One of the appropriate methods to apply seems to be Cost–Benefit Analysis (CBA) for the complex assessment of benefits and costs, aiming to maximise the efficiency of smart solutions [21].

Similarly, Life Cycle Costing (LCC) and Multi-Criteria Decision-Making (MCDM) approaches can support integrated assessments that combine resilience, energy, and sustainability dimensions [22]. The combination of smart city initiatives and resilience thinking advocates a more integrated approach to urban planning and development, resulting in cities that are technologically advanced, robust, and adaptable [23].

Future-oriented urban planning for vulnerability reduction and disaster prevention must therefore embed these economic evaluation methods into smart city decision-support systems, enabling cities to become more robust, adaptable, and resource-efficient [24].

1.3. Scope and Objectives

This study reviews the current body of literature on cost analysis methods for climate adaptation solutions for buildings. Hence, the main objectives are (i) to identify the amount of research focused on the tools and methodologies that seek to optimise investment in climate resilience for buildings, (ii) to define clusters of the methodologies and tools available to ease the proper selection of the best tool in alignment with specific needs, (iii) to discuss the main methodologies and results from each cluster. By doing so, the paper seeks to support stakeholders—such as urban planners, architects, investors, and policymakers—to provide an overview of the most recent building adaptation strategies that have been evaluated through economic assessment and shown to support the long-term resilience of the built environment. While several review articles provide partial insights, they do not address this specific research question. Villalba et al. [25] synthesise MCDM frameworks for building assessment and retrofitting, focusing on methodological breadth rather than cost-based adaptation appraisals. Anwar et al. [26] systematically review life-cycle performance modelling for buildings and bridges under deterioration and hazards, highlighting resilience modelling tools but not comparative cost assessments of adaptation options. Farrokhirad et al. [27] examine vertical greening systems and propose a design framework, but with a narrow technological focus. Against this backdrop, the novelty of our review lies in its exclusive focus on economic evaluation approaches—such as CBA, LCC, and emerging techniques—applied across different adaptation contexts, providing both a structured synthesis and critical insights for practice. Indeed, this study is the first to systematically examine cost-based methods specifically for building adaptation to climate change.

2. Systematic Literature Review: Keywords and Methods

2.1. Search Strategy

A systematic review was conducted between March and June 2025 using electronic academic databases to collect literature relevant to climate adaptation solutions in buildings assessed from an economic perspective. The two databases selected for this review were Web of Science and Scopus, chosen for their extensive indexing of high-quality, peer-reviewed publications and their independence as third-party platforms.

The search covered the time span from 2019 to 2024, since this time range captures the most current developments, trends, and methodological advancements in climate adaptation within the construction sector. The fields of climate adaptation, nature-based solutions, and building sustainability have experienced rapid evolution, driven by new international policy frameworks (e.g., the European Green Deal [28], updated EPBD revisions [29]), technological innovations, and emerging tools for quantifying environmental impacts. The search focused on documents published in English and restricted to the following document types to ensure academic rigour and data uniformity: articles, reviews, conference papers, and books/book chapters.

The search query was developed to identify studies linking climate change adaptation in the built environment with economic evaluation methods and decision-making processes. The search with specific keywords was applied to the title, abstract, and keyword fields; the detailed search string is available in Appendix A.

To situate the scope of this systematic review, Figure 1 illustrates the conceptual boundaries of the literature analysed. Climate adaptation research spans different scales, from urban and territorial strategies to individual buildings. This review narrows this wide field to the building scale and, within this subset, concentrates on studies applying cost assessment methods. Specifically, the analysis targets applications of CBA, LCC, and related economic approaches. This framing highlights both the breadth of the overall adaptation literature and the precise niche addressed by the present study.

2.2. Inclusion and Exclusion Criteria

Following the database search, a total of 1039 records were initially retrieved. Duplicate entries (n = 267) were removed, leaving 772 unique records for screening.

Titles and abstracts were first reviewed to assess the relevance of the content to the core focus of this review: economic assessments of climate adaptation solutions in buildings. At this stage, 641 records were excluded for one or more of the following reasons:

• They only marginally addressed adaptation or economic assessment.
• They focused purely on mitigation strategies or energy efficiency without the adaptation context.
• The built environment was not a primary focus (e.g., agriculture, transport, or infrastructure sectors).

This left 131 articles for full-text review. During this phase, studies were excluded if they did not apply a cost-based method (e.g., CBA, LCC, etc.), if adaptation was not the main subject, or if the methodological description lacked sufficient rigour for systematic analysis. In addition, seismic risk studies were excluded, as earthquakes are not classified as climate-related hazards under the EU Taxonomy (Appendix A) [30].

However, this also reflects the substantial progress achieved in the field of earthquake engineering, where integrated retrofitting approaches—combining structural reinforcement, energy upgrades, and economic feasibility assessments—have been increasingly formalised and applied in recent years.

Ultimately, 39 publications were retained for inclusion in this review. These studies represent the final dataset analysed in detail and illustrated in the PRISMA diagram (Figure 2)—the PRISMA 2020 Checklist [31] is available in the Supplementary Materials. The complete search strategy for each database, including all keywords, Boolean operators, and filters, is provided in Appendix A.

2.3. Analysis Method

To identify trends and thematic concentrations in the literature, the VOSviewer software tool (version 1.6.20) was employed [33,34]. This open-source tool enabled visualisation of keyword co-occurrence networks, helping to detect clusters, emerging themes, and gaps in the literature.

The tool also facilitated an initial thematic mapping based on recurrence and interrelations of key terms such as Cost–Benefit Analysis (CBA), building resilience, and Life Cycle Costing (LCC).

Subsequently, the selected studies were reviewed in detail with a focus on (i) the building type and scale of adaptation measures, (ii) the economic methodologies applied (e.g., CBA, LCC), along with the specific economic indicators and cost input needed to perform the analysis.

This structured approach ensured a critical, reproducible, and transparent assessment of the economic dimension of climate adaptation strategies in the built environment.

3. Results from the Literature

This paper follows a rigorous and methodical approach, adhering to the guidelines of the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) framework [32,35]. PRISMA is a popular instrument for researchers conducting systematic literature reviews (SLR). By following the four key stages of identification, screening, eligibility, and inclusion [36], PRISMA helps ensure that the literature selected aligns with the study’s objectives and maintains a high standard of methodological rigour [37]. The PRISMA 2020 Checklist is available in the Supplementary Materials.

3.1. Statistics

Based on the systematic review of 38 filtered records, targeted analyses were conducted focusing on the building typologies and scales of adaptation measures in relation to the specific hazards addressed, as well as on the economic methodologies applied. In particular, three main clusters of cost assessment methodologies used on building climate adaptation solutions were identified, as presented in Figure 3: (i) cost–benefit analysis (CBA) methods (15 publications), (ii) life-cycle cost (LCC) methods (11 publications), and (iii) other cost assessment methods (12 publications). The first cluster includes studies applying CBA to evaluate the effectiveness of building adaptation measures in relation to specific hazards. The second cluster encompasses research employing LCC approaches to determine the costs associated with specific adaptation interventions during the whole building lifespan. The third cluster comprises studies utilising alternative cost analysis approaches that, while differing from CBA and LCC, still offer valuable insights for the field. An analysis of the annual distribution of the reviewed publications (Figure 3) reveals that studies employing the CBA method (Cluster 1, blue columns) show an overall upward trend, with the highest frequency in 2024 (n = 5). In contrast, studies using the LCC method (Cluster 2, green columns) appear consistently yet with lower frequency. Publications utilising other cost methods (Cluster 3, yellow columns) demonstrate a gradual increase, particularly in 2021 and 2022, indicating a broadening methodological landscape in the economic evaluation of building-related adaptation interventions. It is noteworthy that no publications meeting the inclusion criteria were identified for the year 2019. This gap may reflect the relatively recent emergence of climate adaptation in buildings as a distinct field of economic research, particularly in connection with cost assessment methodologies. The increased attention observed from 2020 onward likely coincides with the growing influence of global policy frameworks and rising awareness of climate-related risks, which have collectively stimulated methodological advancements and empirical applications in this domain. While CBA has been the most frequently applied method, its use has not followed a strictly upward trajectory; for example, a decline is visible between 2020 and 2023. Rather than reflecting methodological superiority, this variation indicates that the choice of method is highly context- and project-dependent. In parallel, recent studies show growing recognition of whole life cycle analyses, underlining the importance of assessing adaptation strategies beyond short-term financial costs.

Regarding the typology of publications, the majority of the results consist of journal articles (n = 33), with only a smaller proportion represented by review papers (n = 3) and conference papers (n = 2), indicating that the evidence base on economic assessments for building adaptation is actively expanding through empirical or case-study-driven contributions, and at the same time, the low number of review papers suggests that syntheses of existing knowledge remain limited.

3.2. Visualising Research Networks

After the statistical analysis, the selected publications were entered into the VOSviewer software, selecting the analysis of word co-occurrence both in titles and abstracts. Full counting was selected, and five was the minimum number of occurrences of a keyword to be shown on the map. The normalisation was performed with the association strength method.

The resulting map in Figure 4 revealed five interconnected thematic clusters. A prominent cluster (red colour) focuses on economic and life cycle aspects of adaptation in construction, reflected by frequent terms such as construction, adaptation measure, cost–benefit analysis, and life cycle cost, highlighting the recurring interest in financial implications and long-term cost evaluations of adaptation measures. Another cluster centres on project-based adaptation interventions (violet colour), linking terms like development, project, intervention, and energy, indicating a strong thematic emphasis on operationalising adaptation through specific projects and evaluating their effectiveness.

The analysis further highlights a robust cluster (green colour) on flood risk management and damage assessment, with keywords including damage, flood risk, property, and benefit, underscoring the importance of evaluating adaptation measures in terms of risk reduction and the protection of assets. Additionally, a cluster (yellow colour) related to the implementation of nature-based solutions (NbS) emerged, with terms such as solution, implementation, economic impact, and NbS, reflecting a growing focus on green adaptation strategies within the reviewed literature.

Finally, a thematic group (blue colour) connected to general development and application within the construction industry was identified, indicating broader methodological and conceptual contributions across the publications. Notably, the keywords development and benefit occupy central positions within the network, demonstrating their bridging role across thematic areas and emphasising the frequent linkage between technical interventions and their socio-economic and environmental benefits. Overall, this co-occurrence analysis illustrates that the reviewed literature extensively covers technical, economic, and risk-focused dimensions of climate adaptation in construction, while also indicating a growing interest in the implementation and economic assessment within this domain.

3.3. Building Types and Scales of Intervention

From the analysis of the eligible papers, it has emerged that residential buildings are the most frequently addressed building type, appearing in various forms, including single-family and multi-family (e.g., [38,39,40]), while commercial buildings are mentioned less frequently (e.g., [41,42]). Additionally, a smaller number of publications refer to educational, medical, and heritage buildings, alongside a few papers that refer to more than one building type, such as “residential and commercial buildings” (e.g., [43,44]) and “residential, commercial, office, and industrial buildings” (e.g., [45,46]). Numerous papers do not specify any particular building typology but instead focus on the whole panorama of building typologies, as seen in He et al. [47] and Pero et al. [48] where energy refurbishment and passive design strategies that could be adopted by any building topology, according to their location, are tested in terms of economic impacts. Overall, the data indicates a clear dominance of residential-focused categories, followed by occasional consideration of mixed-use and commercial typologies, with institutional and heritage buildings playing a minor role in this spectrum of studies.

3.4. Type of Adaptation Measures

The analysis further examined the specific hazards addressed within the reviewed studies. Initially, each paper was assessed to identify the natural climate-related hazards considered, followed by the corresponding adaptation solutions that were subjected to economic evaluation. The majority of the papers focused specifically on flood hazards (n = 12), while several studies investigated combined hazards, such as flood and heatwave or flood and earthquake scenarios. Notably, all hazards examined within the reviewed studies align with those listed in Appendix A of the EU Taxonomy [30], reflecting the priority hazards currently faced by the built environment sector.

When examining the specific adaptation solutions identified, nature-based measures such as mangrove plantation and restoration emerged as prominent strategies for addressing coastal flood and cyclone hazards, demonstrating substantial reductions in flood damage and delivering high returns on investment. In the context of flood hazards, a variety of structural and non-structural measures were investigated, including dry and wet floodproofing, building elevation, Sustainable Urban Drainage Systems (SuDS), and proactive planning tools such as flooded property mapping and scenario-based investment planning. Several studies integrated CBA to identify optimal combinations of these measures at micro and city scales, emphasising the economic viability of targeted adaptation actions. For extreme heat and heatwave conditions, Nature-based Solutions (NbS), including urban forests and Building-Integrated Greenery (BIG), were explored for their effectiveness in improving urban microclimates and thermal comfort, while adaptive comfort strategies within buildings were also highlighted. Combined hazards, such as floods with heatwaves or earthquakes, were addressed through integrated retrofitting. These included exoskeleton structures and thermal insulation, which enhance resilience across multiple risk types. Wind, hurricane, and tornado hazards prompted studies focusing on reinforcing building envelopes and retrofitting wood-frame structures to improve building and community resilience. For wildfire risk, vertical greening systems and localised management plans, including evacuation route planning and fire protection zones, were identified as critical strategies to enhance community preparedness. Finally, adaptation solutions addressing sea-level rise and flood-drought scenarios emphasised building elevation, floodproofing, and the integration of grey and green infrastructure for managing uncertainty in future hazards.

Table 1. An extract about the natural hazards investigated in the eligible publications and the main adaptation solutions reported, including associated references for traceability within the systematic review.

Natural Hazard	Adaptation Solution(s)	Reference(s)
Coastal flood	Mangrove plantation and restoration	[49]
Cyclone	Mangrove restoration, green/grey infrastructure, enforcement of building codes, and risk transfer strategies	[50]
Flood	Dry/wet floodproofing, building elevation, SuDS retrofitting, safety barriers	[41,42,43,44,46,51,52,53,54]
Flood and heatwave	Stormwater infiltration and management, flood protection freeboard, green infrastructure for flood and drought adaptation	[55]
Flood, heatwave and earthquake	Integrated retrofitting with timber/steel/concrete exoskeletons and thermal insulation	[56]
Extreme heat and heatwave	Urban forests, Building-Integrated Greenery (BIG), NbS for microclimate improvement, adaptive comfort strategies	[57,58,59,60]
Sea-level rise	Building elevation, floodproofing for reducing flood risk under uncertain sea level rise conditions.	[39,45]
Tornado	Reinforcing light-frame wood structures, retrofitting for windstorm resilience, and enhancing community-level resilience	[61]
Urban heat island	Vertical Greening Systems (VGS), localised fire management plans including evacuation routes and fire protection zones	[27]
Wind	Reinforcing building envelopes, improving water resistance, strengthening windows, and installing resistant shutters	[38]

presents an extract of the main hazards investigated, along with the main adaptation solutions extracted from the studies. It is important to note that the adaptation solutions may differ from context to context according to the climatic situation.

3.5. Economic Methods

Among the economic assessment methods applied within the reviewed studies, CBA emerged as one of the most frequently utilised approaches. CBA serves as a decision-support tool in the building sector to evaluate the economic viability, efficiency, and broader social impacts of construction projects. It systematically compares the total anticipated costs—including capital, operational, and maintenance expenditures—with the total expected benefits, such as revenues, energy savings, and social value generated over the project’s lifecycle to justify the profitability of the project for achieving the defined aim. Within the context of building-related adaptation measures, CBA assists stakeholders, including architects, engineers, developers, and policymakers, in making informed decisions that align with financial objectives, sustainability goals, and regulatory requirements. Notably, 15 of the analysed articles applied CBA as their primary cost assessment method in evaluating building adaptation interventions.

The second most commonly used method among the reviewed papers, with 11 records, is LCC, which is a comprehensive economic analysis method that evaluates the total cost of ownership of a building over its entire lifespan [62]. It helps decision-makers understand not just the upfront capital costs, but also the long-term financial implications of materials, systems, and design choices, supporting more informed decisions toward sustainable practices [63]. LCC analysis quantifies the cumulative costs incurred at each stage of the building’s lifespan and is governed by ISO 15686-5 [64]. According to this standard, LCC is divided into four primary cost categories: initial investment, including construction, operation and maintenance, replacement, and end-of-life costs (

Table 2. Phases of LCC and associated costs.

Life Cycle Phase	Cost Elements
1. Initial Investment	Design, site preparation, construction, systems installation
2. Operation And Maintenance	Utilities (energy, water), HVAC servicing, cleaning, routine repairs
3. Replacement	Costs of replacing building systems (e.g., roofing, windows, elevators)
4. End-of-Life	Decommissioning, demolition, waste management, and salvage value

). LCC is particularly valuable for sustainable buildings, where higher initial costs are often justified by future savings in energy, maintenance, and environmental impact [65,66].

While both LCC and CBA are tools used to evaluate building projects economically, they serve different purposes, apply different scopes, and produce different outputs [67]. LCC is a cost-focused tool used to select the most economical option over a building’s lifespan, whereas CBA is a value-oriented framework that evaluates whether a building project generates net benefits for society [67]. In a recent study of June 2025, Papangelopoulou et al. [68] systematically analyses various assessment methods applied to building retrofits, addressing gaps in existing literature regarding evaluation practices and integration of environmental and social impacts; in particular, LCC is highlighted as the most used method to assess costs, which is applied in over 60% of the studies reviewed, while CBA is mentioned, appearing in fewer than 25% of cases.

Alternative cost evaluation methods, ranging from artificial intelligence and simulation-based models to MCDM approaches and legal-economic frameworks, have been found among the eligible papers (n = 12). These emerging methods broaden the analytical scope by integrating stakeholder preferences, uncertainty analysis, and complex scenario modelling. The three clusters are examined in greater detail in the following section.

4. Critical Discussion on the Selected Cost Assessment Methods for Building Climate Adaptation Solutions

4.1. CBA Methods

A unifying feature across the publications listed in Table 3 is the application of CBA as a decision-support tool for climate adaptation in the built environment, demonstrating its versatility in evaluating the economic viability of diverse adaptation measures under climate risks.

Several studies emphasise micro-scale, property-specific CBAs to guide efficient investments in flood resilience. For instance, Oladunjoye et al. [41] and De Ruig et al. [42] both demonstrate that building-level CBAs significantly enhance economic efficiency in flood adaptation planning. Oladunjoye et al. [41] develop a choice-modelling CBA framework for Sustainable Urban Drainage Systems (SuDS) in commercial properties, underlining the influence of local flood characteristics and flood return period on investment effectiveness. Similarly, De Ruig et al. [42] apply the HAZUS MH model with depth-damage curves to demonstrate that individualised CBAs can be up to 85% more economically efficient than traditional area-based approaches. Their findings highlight the importance of tailoring adaptation measures—such as dry floodproofing, elevation, and wet floodproofing—to specific inundation depths. Notably, the study conducted CBAs under different scenarios: one reflecting current climate conditions and three others accounting for sea level rise up to 200 cm, evaluating the effectiveness of the three adaptation strategies across these conditions.

Ventimiglia et al. [51] also employ micro-scale CBA using hydraulic modelling data on a case study in Sicily, Italy, to evaluate dry and wet floodproofing interventions for residential areas, highlighting how structural measures, while effective, require optimisation due to high upfront costs. By employing CBA, the study highlights the reduction in the total direct flood damages as a consequence of specific and relevant risk mitigation measures, while costs are the total costs of building or implementing these mitigation measures. The evaluation of the total damage caused by the flooding was achieved by using specific damage–depth curves (damage curves).

Han and Mozumder [39] use a dynamic programming-based CBA combined with Monte Carlo simulations to evaluate the effectiveness of building-level adaptation strategies in response to sea-level rise. Their approach shows strong potential for significantly reducing flood-related damages in Florida, even amid future climate uncertainties. To estimate the effectiveness of different adaptation measures, the study applies damage curves developed by Lasage et al. [69], assuming that all measures are well-maintained and remain effective throughout the simulation period. Annual maintenance costs are incorporated into the analysis—2% of the total adaptation cost for floodproofing measures and 4% for building elevation, following Aerts [70]. The primary evaluation metric is the Benefit-to-Cost Ratio (BCR), defined as the average annual ratio of the net present value of all project benefits to the net present value of associated costs. The findings indicate that communities located near the shoreline tend to have higher BCRs due to their greater vulnerability to storm surge flooding and sea-level rise. Under a low sea-level rise scenario, these shoreline communities show BCRs ranging from 2 to 5, while under high sea-level rise scenarios, their BCRs exceed 5.

In Shan et al. [71], CBA is integrated with Real Options Analysis and Dynamic Adaptive Policy Pathways to optimise the timing of storm flood adaptation investments in Shanghai. This study demonstrates that early, flexible adaptation yields the highest economic returns under deep uncertainty, a perspective aligning with Han and Mozumder’s [39] emphasis on dynamic CBA but extending it by explicitly considering the value of flexibility under evolving climate scenarios. In particular, Shan et al. [71] use vulnerability curves to estimate Expected Annual Damage (EAD), with the benefits of adaptation expressed as the reduction in EAD relative to current levels. They then calculate the Net Present Value (NPV) and BCR for adaptation measures such as dry floodproofing, wet floodproofing, and elevation. These assessments are performed under varying discount rates (4%, 6%, and 8%) and across different Representative Concentration Pathways (RCPs), capturing a range of future climate scenarios.

Maiwald and Schwarz [52] also apply CBA principles by integrating a fragility-function-based flood damage model developed at the Earthquake Damage Analysis Centre (EDAC), allowing for advanced flood protection evaluations under uncertainty. The study includes a realistic reinterpretation of the actual damages observed during the 2002 flood in Saxony. Results are presented for six different study areas characterised by moderate flow velocities. Using the Monte Carlo method, the developed fragility functions support a simulation-based estimation of structural damage to individual buildings, taking into account both water level and flow velocity through two distinct modelling approaches.

Likewise, Friedland et al. [53] developed the FloodSafeHome tool to quantify insurance premium savings and risk reductions from first-floor elevation, framing freeboard as a cost-effective adaptation measure through a practical, CBA-oriented lens. This tool allows users to enter their building information and obtain a customised freeboard cost analysis evaluated based on their preferences and demands.

While flood adaptation dominates many studies, Qin and Stewart [38] apply CBA principles in the context of wind-related hazards, showing that location-specific measures such as window reinforcement are cost-effective only in high-risk areas. The study relies on a previous Probabilistic Risk Assessment (PRA) method previously developed by the authors [72], and it is aimed at reducing housing damage from non-cyclonic windstorms in the context of a changing climate. This PRA framework incorporates probabilistic models for wind hazards and related rainfall, a reliability-based assessment of wind-induced damage, evaluation of rainwater intrusion, and estimation of resulting losses. The economic impacts considered for modern houses include wind damage to metal roof cladding and timber roof framing, damage to windward windows, and rainwater-related damage to the building’s interior, contents, and loss of use.

This emphasis on hazard-specific, localised CBA aligns with the approach taken by flood-focused studies, reinforcing the necessity of integrating hazard intensity and building characteristics into economic evaluations.

NbS are evaluated through CBA in multiple studies. In particular, Bresch and Aznar-Siguan [50] and Narendr et al. [49] both demonstrate that mangrove restoration yields returns exceeding their costs, positioning NbSs as economically advantageous adaptation options. Narendr et al. [49] developed the Flood Resilient Scenario Model (FReSMo), a data-driven, evidence-based tool for assessing climate-induced flood risk and evaluating the effectiveness of mangroves as a nature-based solution. The study demonstrated that planting 6.2 km² of mangroves in the Sagar Island could significantly reduce flood damage to coastal residential buildings, achieving an impressive 222% Return on Investment (ROI). Instead, Bresch and Aznar-Siguan [50] present the concept of probabilistic options appraisal through an extension of the CLIMADA impact modelling platform [73]. The platform enables the comparison of adaptation measures across different regions, and indeed, a case study from the Antilles was presented. Furthermore, CLIMADA can be enhanced with high-resolution hazard models and detailed exposure and impact functions to perform in-depth assessments of targeted locations and adaptation measures, which may be selected based on insights from a preliminary, less detailed analysis. The study also demonstrates that combining measures of different types—such as mangrove restoration, preparedness, building code enforcement, and retrofitting—can significantly increase the amount of averted damage in a cost-effective manner. In Anguilla, for example, mangrove restoration alone is estimated to avert over USD 40 million in expected damages over the next 35 years under a moderate climate change scenario. This accounts for 6% of the expected damage in that scenario and represents more than four times the estimated cost of the restoration.

Wu et al. [74] evaluates vertical and green roof systems as climate adaptation solutions in commercial complexes in Singapore. In particular, it compares three analytical approaches across two scenarios: (1) NPV and Payback Period (PBP) for general buildings, (2) NPV and PBP for commercial complexes, and (3) sensitivity analysis for commercial complexes. The study uses Monte Carlo simulations to address uncertainty and finds that well-designed greening significantly improves economic sustainability, especially in commercial contexts.

Semeraro et al. [59] and Iliadis et al. [43] highlight the cost-effectiveness of urban forests and blue-green infrastructure (BGI) for heat and flood mitigation, respectively, illustrating the scalability of CBA for nature-based adaptation strategies. Semeraro et al. [59] combine CBA results with ENVI-met (version 5.0.3) [75] microclimate simulations to assess different implementation scenarios. For each intervention, they calculate the NPV and BCR. The different greening strategies are indeed simulated in the software to evaluate not only their economic performance but also their environmental and thermal comfort benefits.

More in detail, Iliadis et al. [43] apply a CBA method where benefits are calculated by subtracting flood damages under maximum intervention scenarios from those in the baseline. Interventions such as permeable pavements, water butts, green roofs, and storage ponds are simulated to assess their impact. Buildings are classified by flood risk through exposure analysis to refine damage estimates. Finally, baseline and intervention scenarios are compared to identify the most cost-effective measures for reducing flood damage.

Pérez et al. [60] acknowledges the increase in property value from green roofs (estimated at 6–10%) and provides indicative maintenance costs (~40 €/m² year), but it also highlights a gap in comprehensive cost-related evaluations, particularly regarding the monetization of ecosystem services, underscoring the need for more detailed economic analysis to support long-term sustainability of BIG systems.

While most studies utilise CBA for physical adaptation measures, Röck et al. [76] critique current building stock modelling approaches for their insufficient incorporation of life-cycle assessments and sensitivity analyses, suggesting that CBA frameworks need to be complemented with holistic environmental and system-wide analyses to inform effective, long-term adaptation strategies in the EU building stock.

In summary, the reviewed CBA studies consistently demonstrate that adaptation effectiveness depends on context-specific, detailed, and dynamic assessments, whether through micro-scale CBAs, nature-based solutions, advanced modelling, or integrated urban planning tools. At the building level, micro-scale CBAs of floodproofing, elevation, or SuDS retrofits often yield more accurate and economically efficient outcomes than aggregated approaches, sometimes improving efficiency by more than 80%. Studies also show the economic value of targeted adaptation under local hazard conditions, from flood and sea-level rise to windstorms and seismic risks, underscoring the flexibility of the method across hazards and building typologies. At the same time, several limitations persist: high upfront investment costs may restrict uptake; intangible and co-benefits such as health, biodiversity, or equity are rarely monetised; and methodological complexity, combined with limited data availability, continues to constrain real-world application.

Table 3. Summary of selected records from the literature research—CBA assessed building adaptation solutions.

Reference	Year	Typology of Building	Natural Hazard Addressed	Adaptation Solution	Methodology	Economic Indicator	Cost Input	Method
Oladunjoye et al. [41]	2020	Commercial buildings	Flood	Retrofit of Sustainable Urban Drainage Systems (SuDS)	Conceptualisation	NPV	Cost of the installation of the SuDS retrofit step by step	Discounting
de Ruig et al. [42]	2020	Commercial buildings	Flood	Dry-floodproofing, wet-floodproofing and building elevation	Conceptualisation, hazard maps, case study (California—USA), numerical analyses	NPV	FEMA estimation costs	Discounting
Qin and Stewart [38]	2020	Residential buildings	Wind	Reinforcing building envelopes, improving water resistance, strengthening windows, and adding shutters	Conceptualisation, hazard maps, case study (Australia), numerical analyses	NPV	Cost data from national cost guides	Discounting
Ventimiglia et al. [51]	2020	Residential buildings and agricultural areas	Flood	Dry and wet floodproofing with flood barriers, combined with structural measures	Conceptualisation, case study (Sicily region—Italy), numerical analyses	Benefits compared to a base scenario	ISPRA JRC estimation and local material price lists	Other
Han and Mozumder [39]	2021	Residential buildings	Sea level rise	Floodproofing and building elevation	Conceptualisation, case study (Florida—USA), numerical analyses	BCR	Literature and national costs	BCR
Röck et al. [76]	2021	Residential buildings—single and multi	General adaptation to climate change	Adaptable building design to different climate changes	Conceptualisation	Different indicators	Statistical data from building material databases	Different methods
Bresch and Aznar-Siguan [50]	2021	All buildings	Cyclone	Green and grey infrastructure, mangrove restoration, building code enforcement, and risk transfer measures	Conceptualisation, case study (Antilles), numerical analyses	NPV and BCR	-	BCR
Shan et al. [71]	2022	Residential buildings	Storm flood	Wet-floodproofing, dry-floodproofing, and elevation for flood control	Conceptualisation, case study (Shanghai, China), hazard maps, numerical analyses	NPV and BCR	Building cost data from the Shanghai Statistical Yearbooks (1995–2019), and predictions for future construction costs	BCR
Maiwald and Schwarz [52]	2022	Residential buildings	Flood	Different flood protection measures	Conceptualisation, case study (Saxony region, Germany), numerical analyses	BCR	Damage dataset compiled after the 2002 flood in Germany	BCR
Friedland et al. [53]	2023	Residential buildings	Flood	Increasing first-floor elevation and adding freeboard	Conceptualisation, case study (USA), numerical analyses	Annual premium savings, annual avoided loss, monthly total savings	Building attributes, insurance parameters, FEMA directives	Other
Wu et al. [74]	2024	Commercial buildings	Generic climate-related hazards	Vertical greening and green roofs	Conceptualisation, case study (Singapore), numerical analyses	NPV, PBP, Sensitivity Analysis	Discount rates, inflation rates, growth rates of manpower costs, and benefit calculation periods	Discounting
Semeraro et al. [59]	2024	All buildings	Extreme heat	Nature-based solutions (NbS) using urban forests	Conceptualisation, case study (Puglia region, Italy), numerical analyses	NPV and BCR	Puglia regional price list	BCR
Iliadis et al. [43]	2024	Residential and commercial buildings	Flood	SuDS, Blue-Green Infrastructure, and permeable pavements	Conceptualisation, case study (Newcastle upon Tyne, UK), numerical analyses	Benefits given from the difference between flood damages in the baseline scenario and those in intervention scenarios for a given return period	Handbook for Economic Appraisal (2022)	Other
Pérez et al. [60]	2024	All buildings	Extreme heat	Building-Integrated Greenery (green roofs, walls, facades)	Conceptualisation, case study (Barcelona, Spain), numerical analyses	Increase in property value and maintenance and implementation costs	Local maintenance costs	Other
Narendr et al. [49]	2024	Residential buildings	Coastal flood	Mangrove plantation as an NbS	Conceptualisation, case study (Sagar Island, India), hazards maps and projections, numerical analyses	Costs pre-post interventions, ROI	Estimations based on multiple Southeast Asian case studies	Other

Note: Net present value (NPV), Benefit-to-Cost Ratio (BCR), Payback Period (PBP), Return On Investment (ROI).

Table 3. Summary of selected records from the literature research—CBA assessed building adaptation solutions.

Reference	Year	Typology of Building	Natural Hazard Addressed	Adaptation Solution	Methodology	Economic Indicator	Cost Input	Method
Oladunjoye et al. [41]	2020	Commercial buildings	Flood	Retrofit of Sustainable Urban Drainage Systems (SuDS)	Conceptualisation	NPV	Cost of the installation of the SuDS retrofit step by step	Discounting
de Ruig et al. [42]	2020	Commercial buildings	Flood	Dry-floodproofing, wet-floodproofing and building elevation	Conceptualisation, hazard maps, case study (California—USA), numerical analyses	NPV	FEMA estimation costs	Discounting
Qin and Stewart [38]	2020	Residential buildings	Wind	Reinforcing building envelopes, improving water resistance, strengthening windows, and adding shutters	Conceptualisation, hazard maps, case study (Australia), numerical analyses	NPV	Cost data from national cost guides	Discounting
Ventimiglia et al. [51]	2020	Residential buildings and agricultural areas	Flood	Dry and wet floodproofing with flood barriers, combined with structural measures	Conceptualisation, case study (Sicily region—Italy), numerical analyses	Benefits compared to a base scenario	ISPRA JRC estimation and local material price lists	Other
Han and Mozumder [39]	2021	Residential buildings	Sea level rise	Floodproofing and building elevation	Conceptualisation, case study (Florida—USA), numerical analyses	BCR	Literature and national costs	BCR
Röck et al. [76]	2021	Residential buildings—single and multi	General adaptation to climate change	Adaptable building design to different climate changes	Conceptualisation	Different indicators	Statistical data from building material databases	Different methods
Bresch and Aznar-Siguan [50]	2021	All buildings	Cyclone	Green and grey infrastructure, mangrove restoration, building code enforcement, and risk transfer measures	Conceptualisation, case study (Antilles), numerical analyses	NPV and BCR	-	BCR
Shan et al. [71]	2022	Residential buildings	Storm flood	Wet-floodproofing, dry-floodproofing, and elevation for flood control	Conceptualisation, case study (Shanghai, China), hazard maps, numerical analyses	NPV and BCR	Building cost data from the Shanghai Statistical Yearbooks (1995–2019), and predictions for future construction costs	BCR
Maiwald and Schwarz [52]	2022	Residential buildings	Flood	Different flood protection measures	Conceptualisation, case study (Saxony region, Germany), numerical analyses	BCR	Damage dataset compiled after the 2002 flood in Germany	BCR
Friedland et al. [53]	2023	Residential buildings	Flood	Increasing first-floor elevation and adding freeboard	Conceptualisation, case study (USA), numerical analyses	Annual premium savings, annual avoided loss, monthly total savings	Building attributes, insurance parameters, FEMA directives	Other
Wu et al. [74]	2024	Commercial buildings	Generic climate-related hazards	Vertical greening and green roofs	Conceptualisation, case study (Singapore), numerical analyses	NPV, PBP, Sensitivity Analysis	Discount rates, inflation rates, growth rates of manpower costs, and benefit calculation periods	Discounting
Semeraro et al. [59]	2024	All buildings	Extreme heat	Nature-based solutions (NbS) using urban forests	Conceptualisation, case study (Puglia region, Italy), numerical analyses	NPV and BCR	Puglia regional price list	BCR
Iliadis et al. [43]	2024	Residential and commercial buildings	Flood	SuDS, Blue-Green Infrastructure, and permeable pavements	Conceptualisation, case study (Newcastle upon Tyne, UK), numerical analyses	Benefits given from the difference between flood damages in the baseline scenario and those in intervention scenarios for a given return period	Handbook for Economic Appraisal (2022)	Other
Pérez et al. [60]	2024	All buildings	Extreme heat	Building-Integrated Greenery (green roofs, walls, facades)	Conceptualisation, case study (Barcelona, Spain), numerical analyses	Increase in property value and maintenance and implementation costs	Local maintenance costs	Other
Narendr et al. [49]	2024	Residential buildings	Coastal flood	Mangrove plantation as an NbS	Conceptualisation, case study (Sagar Island, India), hazards maps and projections, numerical analyses	Costs pre-post interventions, ROI	Estimations based on multiple Southeast Asian case studies	Other

Note: Net present value (NPV), Benefit-to-Cost Ratio (BCR), Payback Period (PBP), Return On Investment (ROI).

4.2. LCC Methods

A notable cluster of studies applies Life Cycle Cost analysis (LCC) to explore climate adaptation strategies in the built environment, often combining them with environmental LCA and advanced modelling techniques (Table 4).

For example, Adhikari et al. [61] and Nydahl et al. [77] both demonstrate that enhanced resilience measures, despite higher upfront costs, can align with low-carbon objectives, revealing synergies between long-term economic and environmental benefits. Adhikari et al. [61] focus on tornado resilience in wood-frame residential buildings, while Nydahl et al. [77] introduces an Extended Life Cycle Cost Assessment (ELCCA) approach that incorporates both traditional economic costs and the monetary evaluation of climate risks using the Social Cost of Carbon (SCC). Key highlights include the use of average electricity and heating prices in Sweden—0.183 EUR/kWh and 0.086 EUR/kWh, respectively—with an assumed annual real price increase of 3%. These inputs enable a realistic assessment of operational energy costs over the building’s life span. The study demonstrates that renovation consistently outperforms new construction in both climate impact and cost-efficiency, even when a flat greenhouse gas tax is applied. However, both studies acknowledge the limitations in capturing indirect and post-service-life costs and challenges in systematically evaluating climate risks within LCC.

Similarly, Plebankiewicz et al. [78] and Fregonara and Ferrando [79] employ LCC with probabilistic methods and Monte Carlo simulations to evaluate whole-life costs; Plebankiewicz et al. [78] confirms the reliability of fuzzy and probabilistic methods for sustainability assessments, while Fregonara and Ferrando [79] demonstrate the influence of repair intervals and component lifespans on equivalent annual costs for window system maintenance. Both studies highlight challenges such as market volatility, lifespan uncertainties, and limited empirical validation that constrain the robust application of LCC for adaptation planning.

The integration of dynamic energy performance modelling with LCC for climate adaptation is evident in Heracleous et al. [57] and Ashrafian [58]. On the one hand, Heracleous et al. [57] evaluate retrofit options in educational buildings under energy efficiency and emissions goals using Integrated Environmental Solutions (IES-VE) [80]; results show that mechanical ventilation alone can reduce energy consumption by 49%, while combined retrofitting scenarios achieve energy savings between 62% and 77%. On the other hand, Ashrafian [58] analyzes retrofit strategies under heatwave scenarios in Turkish schools, such as insulation, shading and natural ventilation. Retrofitting options were labelled based on combinations of building envelope and system upgrades—such as PV4GL3 and PV4OP4GL4—reflecting different levels of photovoltaic integration, glazing, and opaque elements. Results show that PV4OP4GL4, which combines high-performance opaque elements, triple glazing, and full PV integration, achieves both the lowest Predicted Percentage of Dissatisfied (PPD) and a low net present cost, making it the most thermally and economically optimal choice. In contrast, simpler upgrades like PV4GL3 show higher discomfort levels and longer payback periods.

Both studies highlight barriers, including high upfront costs, long payback periods, and high deviations in climate and behavioural data, which hinder widespread adoption of retrofits despite operational benefits.

In contrast, Wang et al. [81] extend LCC analysis to building portfolios post-disaster, using Monte Carlo simulations to balance risk preferences in community-scale reconstruction, a scale and stakeholder dimension less explored by others. However, their approach faces challenges in dynamic adaptability and lacks granularity across diverse building types, limiting its precision for targeted climate adaptation investment planning.

Ekström et al. [82] similarly integrate PRA with LCC to account for stakeholder perspectives under uncertainty during design phases, revealing tensions between short-term developer cost minimisation and long-term owner resilience preferences. This stakeholder differentiation contrasts with studies like Adhikari et al. [61] and Heracleous et al. [57], which primarily consider operational cost and resilience benefits from a societal perspective.

Studies by Caruso et al. [56] and Trovato and Cappello [83] advance this discussion by embedding LCC within MCDM frameworks. Caruso et al. [56] combine seismic and climate-related loss estimation with energy and environmental impacts—key economic inputs include a reconstruction cost of €1350/m² and demolition/disposal costs of €44/m³, resulting in a total replacement cost of approximately €1.4 million for a residential building case study (from the 70s) in Brescia, Italy. By integrating these costs with environmental and social indicators, the study supports the selection of retrofit solutions—such as timber, steel, and concrete exoskeletons—that balance structural resilience, energy efficiency, and cost-effectiveness across the building’s life cycle.

Furthermore, Trovato and Cappello [83] integrate LCC with environmental LCA and GIS-based multicriteria assessments to guide adaptation strategies in historic centres. Both highlight the benefits of Life Cycle Thinking for comprehensive retrofit planning but acknowledge challenges in quantifying retrofit invasiveness, handling non-quantifiable factors, and managing decision-making complexity under uncertainty. From a NbS perspective, Farrokhirad et al. [27] and Gholami [55] explore alternative pathways. Farrokhirad et al. [27] demonstrate that Vertical Greening Systems (VGS) can be assessed using life cycle assessment and cost-related analyses, drawing on several examples from the literature (e.g., [84,85,86]). Their findings highlight the potential of VGS in mitigating urban heat island effects, while also noting key limitations—namely, high initial investment costs, extended payback periods, and insufficient monitoring practices that hinder both cost-efficiency and performance evaluation.

Gholami [55] proposes a Multi-Criteria Assessment (MCA) framework for the deployment of solar technologies on urban surfaces. Notably, the framework also supports the integration of complementary solutions that promote rainwater retention and infiltration, such as green roofs, permeable pavements, and rain gardens. The MCA approach evaluates a broad set of decision alternatives using a comprehensive range of criteria, spanning social and health aspects, environmental considerations, and economic performance. Economic assessment is conducted using LCC, capturing all relevant costs—from initial acquisition and installation to operation, maintenance, and eventual disposal or end-of-life stages. While this systematic review covered literature published up to the end of 2024, it is worth noting that very recent studies continue to expand this field. For instance, Le et al. [87] introduced a heuristic MCDM framework that adapts retrofit solutions to local climate conditions across cities, aiming to minimise LCC while addressing energy use and thermal comfort. Although not included in our formal dataset due to the cut-off date, this work exemplifies the ongoing development of advanced cost evaluation methods for building adaptation.

Table 4. Summary of selected records from the literature research—LCC assessed building adaptation solutions.

Reference	Year	Typology of Building	Natural Hazard Addressed	Adaptation Solution	Methodology	Economic Indicators	Cost Input
Adhikari et al. [61]	2020	Residential buildings	Tornado	Strengthening light-frame wood construction	Conceptualisation, fictional case study, numerical analysis	PV, initial cost, periodic repair/maintenance cost, and costs of repair damage following the occurrence of a tornado	RS Means Residential Cost Data [88] (initial cost, periodic repair/maintenance cost, and costs of repairing damage following the occurrence of a tornado)
Wang et al. [81]	2020	All buildings	Hurricane and Earthquake	“Building Back Better” approach	Conceptualisation, fictional case study, numerical analysis	Cost of new buildings; cost of building damages due to future hazard exposure; cost associated with casualties (e.g., injuries or fatalities) caused by future disasters; indirect losses due to building functionality loss	FEMA Technical Manual
Fregonara and Ferrando [79]	2020	Residential, commercial, and office buildings	General adaptation to climate change	Aluminium Frame and a Timber one for a glass façade	Conceptualisation	Annuity Cost, initial investment costs, total running and replacement costs, and disposal costs	National investment costs
Ekström et al. [82]	2021	Residential buildings	General adaptation to climate change	Generic building design optimisation	Conceptualisation, component case study, numerical analysis	Acquisition cost, operational costs, real interest rate, real price change, discounting over a 60-year analysis period	Industry organisations and government data sources
Nydahl et al. [77]	2022	All buildings	General adaptation to climate change	Generic building design	Conceptualisation, case study (Umeå, Sweden), numerical analysis	Disposal cost from partial or full demolition of the original building, investment cost and operational energy cost	Literature sources
Heracleous et al. [57]	2022	Educational buildings	Extreme heat	Retrofitting strategies (e.g., roof insulation)	Conceptualisation, case study (Nicosia, Cyprus), numerical analysis	PV, initial investment, the sum of annual costs for every year (including replacement costs), and the real interest rate	Several literature sources
Trovato and Cappello [83]	2022	All buildings	General adaptation to climate change	Green roof, building-integrated photovoltaic system	Conceptualisation, case study (Syracuse, Italy), numerical analysis	Initial investment, maintenance cost, maintenance and replacement cost, dismantling and disposal cost, RV, Discount Rate, NPV, TRR	Regional price of public works
Ashrafian [58]	2023	Educational buildings	Heatwave	Adaptive comfort strategies	Conceptualisation, fictional case study in Turkey, numerical analysis	Present value (PV), energy cost, maintenance cost, replacement cost, cost of greenhouse gas emission, and residual value	Price lists of local distributors
Caruso et al. [56]	2024	Residential buildings	Earthquake, flood and heatwave	Integrated retrofitting with timber, steel, concrete exoskeletons, and insulation	Conceptualisation, case study (Brescia, Italy), numerical analysis	Post-retrofit life cycle costs, summing up the costs of the retrofit materials and installation, seismic economic losses, and costs for energy consumption, normalised by the building’s floor area and the post-retrofit service life	Literature sources
Gholami [55]	2024	All buildings	Extreme heat and floods	Building integrated photovoltaics	Conceptualisation	Generic list of indicators, including initial costs, operating and maintenance costs, and end-of-life costs, NPV, ROI, etc.	n/a
Farrokhirad et al. [27]	2024	All buildings	Extreme heat	Vertical Greening Systems (VGS)	Conceptualisation	Generic list of indicators, including initial costs, operating and maintenance costs, and end-of-life costs	n/a

Note: Net present value (NPV), Present value (PV), Benefit-to-Cost Ratio (BCR), Payback Period (PBP), Return On Investment (ROI), Residual Value (VR), Total Rate of Return (TRR), n/a stands for ‘not available’ or ‘not specified’.

Table 4. Summary of selected records from the literature research—LCC assessed building adaptation solutions.

Reference	Year	Typology of Building	Natural Hazard Addressed	Adaptation Solution	Methodology	Economic Indicators	Cost Input
Adhikari et al. [61]	2020	Residential buildings	Tornado	Strengthening light-frame wood construction	Conceptualisation, fictional case study, numerical analysis	PV, initial cost, periodic repair/maintenance cost, and costs of repair damage following the occurrence of a tornado	RS Means Residential Cost Data [88] (initial cost, periodic repair/maintenance cost, and costs of repairing damage following the occurrence of a tornado)
Wang et al. [81]	2020	All buildings	Hurricane and Earthquake	“Building Back Better” approach	Conceptualisation, fictional case study, numerical analysis	Cost of new buildings; cost of building damages due to future hazard exposure; cost associated with casualties (e.g., injuries or fatalities) caused by future disasters; indirect losses due to building functionality loss	FEMA Technical Manual
Fregonara and Ferrando [79]	2020	Residential, commercial, and office buildings	General adaptation to climate change	Aluminium Frame and a Timber one for a glass façade	Conceptualisation	Annuity Cost, initial investment costs, total running and replacement costs, and disposal costs	National investment costs
Ekström et al. [82]	2021	Residential buildings	General adaptation to climate change	Generic building design optimisation	Conceptualisation, component case study, numerical analysis	Acquisition cost, operational costs, real interest rate, real price change, discounting over a 60-year analysis period	Industry organisations and government data sources
Nydahl et al. [77]	2022	All buildings	General adaptation to climate change	Generic building design	Conceptualisation, case study (Umeå, Sweden), numerical analysis	Disposal cost from partial or full demolition of the original building, investment cost and operational energy cost	Literature sources
Heracleous et al. [57]	2022	Educational buildings	Extreme heat	Retrofitting strategies (e.g., roof insulation)	Conceptualisation, case study (Nicosia, Cyprus), numerical analysis	PV, initial investment, the sum of annual costs for every year (including replacement costs), and the real interest rate	Several literature sources
Trovato and Cappello [83]	2022	All buildings	General adaptation to climate change	Green roof, building-integrated photovoltaic system	Conceptualisation, case study (Syracuse, Italy), numerical analysis	Initial investment, maintenance cost, maintenance and replacement cost, dismantling and disposal cost, RV, Discount Rate, NPV, TRR	Regional price of public works
Ashrafian [58]	2023	Educational buildings	Heatwave	Adaptive comfort strategies	Conceptualisation, fictional case study in Turkey, numerical analysis	Present value (PV), energy cost, maintenance cost, replacement cost, cost of greenhouse gas emission, and residual value	Price lists of local distributors
Caruso et al. [56]	2024	Residential buildings	Earthquake, flood and heatwave	Integrated retrofitting with timber, steel, concrete exoskeletons, and insulation	Conceptualisation, case study (Brescia, Italy), numerical analysis	Post-retrofit life cycle costs, summing up the costs of the retrofit materials and installation, seismic economic losses, and costs for energy consumption, normalised by the building’s floor area and the post-retrofit service life	Literature sources
Gholami [55]	2024	All buildings	Extreme heat and floods	Building integrated photovoltaics	Conceptualisation	Generic list of indicators, including initial costs, operating and maintenance costs, and end-of-life costs, NPV, ROI, etc.	n/a
Farrokhirad et al. [27]	2024	All buildings	Extreme heat	Vertical Greening Systems (VGS)	Conceptualisation	Generic list of indicators, including initial costs, operating and maintenance costs, and end-of-life costs	n/a

Note: Net present value (NPV), Present value (PV), Benefit-to-Cost Ratio (BCR), Payback Period (PBP), Return On Investment (ROI), Residual Value (VR), Total Rate of Return (TRR), n/a stands for ‘not available’ or ‘not specified’.

The reviewed LCC studies underline the importance of adopting a life-cycle perspective to assess the long-term economic viability of adaptation strategies across diverse building types, ranging from single-family houses [61] to educational buildings [57], historic centres [83], and experimental systems such as vertical greening [27]. These works consistently show that upfront investments in resilience and efficiency can be offset by reduced maintenance, energy demand, or hazard-induced damage costs over time. At the same time, advanced LCC approaches increasingly incorporate uncertainty and risk modelling (e.g., probabilistic and fuzzy approaches, stochastic annuity methods), as well as climate-related externalities through the monetisation of greenhouse gas emissions (Extended LCC with the SCC) [77]. Despite these advances, several challenges persist: long payback periods limit the attractiveness of retrofits, especially in schools or vertical greening systems; many applications remain theoretical or scenario-based rather than grounded in observed cost data; and the integration of LCC into early design decisions or broader policy instruments remains limited. Nevertheless, LCC provides a robust framework for capturing long-term cost efficiency and sustainability trade-offs, particularly when combined with environmental and social metrics, thereby offering a bridge between traditional economic assessment and multi-criteria approaches to climate-resilient building design.

4.3. Other Cost Methods

While the previous two clusters presented publications focused on cost assessment rooted, respectively, in CBA and LCC methods, a distinct cluster of alternative methods also emerged among the reviewed publications (Table 5).

Tayefeh Hashemi et al. [89] and Ahmed et al. [90] both explore the emerging but ex-perimental role of machine learning techniques and Artificial Neural Networks (ANNs) in climate adaptation cost estimation. Tayefeh Hashemi et al. [89] critically review 92 papers that focused on ANNs, regression analysis, case-based reasoning, and hybrid models across diverse infrastructure sectors (including buildings, e.g., [91,92]), emphasising their potential for early-stage accuracy but noting limitations such as interpretability challenges, regional data gaps, and high computational demands. Ahmed et al. [90] broaden the perspective by reviewing ANN’s potential for optimising material use, energy management, and project planning, highlighting their role in cost prediction, damage assessment, and financial management. The review identified the work of Elmousalami [93], for example, which provided a comprehensive overview of AI-based cost estimation models, Oduyemi et al. [94], who used ANN to evaluate the LCC of existing buildings, Chao and Kuo [95] employed it to estimate minimum over-head and markup rates, and Shiha [96] applied ANN to predict the cost of building materials in the Egyptian market. Collectively, these studies highlight the versatility and growing reliability of ANN models in addressing various cost-related challenges in construction.

A different methodological direction is taken by He et al. [47], who developed a genetic algorithm (GA) and a Monte Carlo-based model to optimise climate-specific retrofit measures for building energy efficiency. Using NPV analysis, they demonstrate cost-effective pathways to 30–40% energy savings through measures like lighting up-grades and insulation, directly addressing adaptation through energy retrofits.

Similarly, focusing on stakeholder learning but through an innovative lens, Teague et al. [97] introduce a serious gaming framework (Multi-Hazard Tournament) with a web-based tool for evaluating adaptation options for water-related hazards. Using CBA and flood modelling within a participatory environment, they show that serious gaming enhances community awareness, investment decisions, and collaborative planning for hazard mitigation, demonstrating an interactive approach to cost-effective adaptation planning.

Table 5. Summary of selected records from the literature research—building adaptation solutions with other cost assessments.

Reference	Year	Typology of Building	Natural Hazard Addressed	Adaptation Solution	Methodology	Cost Method	Economic Indicators	Cost Input
Tayefeh Hashemi et al. [89]	2020	All buildings	n/a	Generic building design	Review	Use of statistical models, regression analysis, optimisation techniques and machine learning techniques	n/a	Literature for each application area (construction sector)
He et al. [47]	2021	All buildings	General adaptation to climate change	Upgrading building components such as wall insulation, window glazing, and heating systems	Conceptualisation, modelling, case study (Yunnan province, China), numerical analyses	Energy cost-based approach	NPV	Local market price lists
Teague et al. [97]	2021	All buildings	Flood, drought	Various adaptation options	Conceptualisation, modelling, case study	Estimation of costs incurred by governmental entities and CBA	n/a	Associated with the adaptation options, but the sources are not specified
Pero et al. [48]	2021	All buildings	General adaptation to climate change	Passive climate-design strategies for cooling	Conceptualisation, case study (Mogadishu, Somalia), numerical analyses	Price list	Cost/m2 of the adopted solution	Market survey for a construction costs database for the Somali context
Ahmed et al. [90]	2022	All buildings	n/a	Generic building design	Review	Artificial Neural Networks (ANNs)	n/a	n/a
Porter et al. [44]	2022	Commercial and multi-residential buildings	Flood	Generic building design	Conceptualisation, case study (USA), numerical analyses	Component-based damage functions with both direct and indirect costs	Damage value in USD aligned with downtime	(1) state and county-level GDP information, (2) mappings between economic sectors and land-uses, (3) economic multipliers by state and sector
Xie et al. [45]	2022	Residential, commercial, industrial, agricultural, and governmental buildings	Flood and sea-level rise	Generic building design	Conceptualisation, case study, (Tampa, USA), hazard maps, numerical analyses	Total economic costs by identifying flood-prone properties through the comparison of high-resolution elevation data	n/a	Parcel-level property tax GIS data
Dolores et al. [40]	2022	Residential buildings—multi	General adaptation to climate change	Energy retrofit with/without photovoltaic system	Conceptualisation, case study (Campania region, Italy), numerical analyses	Cost-Revenue Analysis (CRA)	NPV, IRR, PP	Estimation through price lists
Tu et al. [46]	2023	Residential, commercial, office, and industrial buildings	Flood	Several flood adaptation measures (hard and soft)	Conceptualisation, case study (Shanghai, China), hazard maps, numerical analyses	Construction cost-based approach with CBA	Average construction cost (USD per m2)	ARCADIS 2019 annual report on different building types
de Pedro et al. [98]	2023	All buildings	General adaptation to climate change	Copper slag as a partial cement substitute	Conceptualisation, fictional case study, numerical analyses	Comparison of costs between new solutions and a baseline	Total cost in USD	Average of the costings of contractors in the Philippines
He and Faure [54]	2024	All buildings	Flood	Post-disaster construction in different countries	Review	Welfare maximisation and evaluation of various instruments for post-disaster recovery	n/a	n/a
Villalba et al. [25]	2024	Residential and educational buildings	Natural hazards	Conceptualisation	Review	Cost minimisation on both tangible (costs of the repair; construction and installation) and intangible (tax incentives from the Italian government) costs	Construction costs and maintenance costs	n/a

Note: Net present value (NPV), Payback Period (PBP), Return On Investment (ROI), n/a stands for ‘not available’ or ‘not specified’.

Table 5. Summary of selected records from the literature research—building adaptation solutions with other cost assessments.

Reference	Year	Typology of Building	Natural Hazard Addressed	Adaptation Solution	Methodology	Cost Method	Economic Indicators	Cost Input
Tayefeh Hashemi et al. [89]	2020	All buildings	n/a	Generic building design	Review	Use of statistical models, regression analysis, optimisation techniques and machine learning techniques	n/a	Literature for each application area (construction sector)
He et al. [47]	2021	All buildings	General adaptation to climate change	Upgrading building components such as wall insulation, window glazing, and heating systems	Conceptualisation, modelling, case study (Yunnan province, China), numerical analyses	Energy cost-based approach	NPV	Local market price lists
Teague et al. [97]	2021	All buildings	Flood, drought	Various adaptation options	Conceptualisation, modelling, case study	Estimation of costs incurred by governmental entities and CBA	n/a	Associated with the adaptation options, but the sources are not specified
Pero et al. [48]	2021	All buildings	General adaptation to climate change	Passive climate-design strategies for cooling	Conceptualisation, case study (Mogadishu, Somalia), numerical analyses	Price list	Cost/m2 of the adopted solution	Market survey for a construction costs database for the Somali context
Ahmed et al. [90]	2022	All buildings	n/a	Generic building design	Review	Artificial Neural Networks (ANNs)	n/a	n/a
Porter et al. [44]	2022	Commercial and multi-residential buildings	Flood	Generic building design	Conceptualisation, case study (USA), numerical analyses	Component-based damage functions with both direct and indirect costs	Damage value in USD aligned with downtime	(1) state and county-level GDP information, (2) mappings between economic sectors and land-uses, (3) economic multipliers by state and sector
Xie et al. [45]	2022	Residential, commercial, industrial, agricultural, and governmental buildings	Flood and sea-level rise	Generic building design	Conceptualisation, case study, (Tampa, USA), hazard maps, numerical analyses	Total economic costs by identifying flood-prone properties through the comparison of high-resolution elevation data	n/a	Parcel-level property tax GIS data
Dolores et al. [40]	2022	Residential buildings—multi	General adaptation to climate change	Energy retrofit with/without photovoltaic system	Conceptualisation, case study (Campania region, Italy), numerical analyses	Cost-Revenue Analysis (CRA)	NPV, IRR, PP	Estimation through price lists
Tu et al. [46]	2023	Residential, commercial, office, and industrial buildings	Flood	Several flood adaptation measures (hard and soft)	Conceptualisation, case study (Shanghai, China), hazard maps, numerical analyses	Construction cost-based approach with CBA	Average construction cost (USD per m2)	ARCADIS 2019 annual report on different building types
de Pedro et al. [98]	2023	All buildings	General adaptation to climate change	Copper slag as a partial cement substitute	Conceptualisation, fictional case study, numerical analyses	Comparison of costs between new solutions and a baseline	Total cost in USD	Average of the costings of contractors in the Philippines
He and Faure [54]	2024	All buildings	Flood	Post-disaster construction in different countries	Review	Welfare maximisation and evaluation of various instruments for post-disaster recovery	n/a	n/a
Villalba et al. [25]	2024	Residential and educational buildings	Natural hazards	Conceptualisation	Review	Cost minimisation on both tangible (costs of the repair; construction and installation) and intangible (tax incentives from the Italian government) costs	Construction costs and maintenance costs	n/a

Note: Net present value (NPV), Payback Period (PBP), Return On Investment (ROI), n/a stands for ‘not available’ or ‘not specified’.

Pero et al. [48] and De Pedro et al. [98] explore practical low-cost adaptation measures. The first [48] develops a climate-responsive housing model for Mogadishu (Somalia) that combines optimised design, photovoltaic systems, and rainwater harvesting, reducing construction costs while promoting local industry and renewables. The main challenge they encountered in conducting the cost assessment was the lack of data on construction material costs specific to the Somali market. To address this issue, they initiated the development of a new construction cost database by conducting interviews with local construction companies, allowing them to estimate unit costs for various materials and activities. In a complementary vein, De Pedro et al. [92] combine LCA and cost analysis to assess copper slag as a cement replacement in low- and mid-rise buildings in the Philippines, demonstrating modest cost (−1.40% reduction compared to the traditional scenario) and emission reductions while highlighting trade-offs in other environmental categories.

Porter et al. [44] and Xie et al. [45] both focus on flood-related cost estimation, though with different approaches. Porter et al. [44] develop a component-based depth-damage and economic multiplier framework to assess flood risks for commercial and residential buildings, projecting a 25–30% increase in damages under climate change. It is particularly interesting because flood risk is quantified in terms of structural damage costs, business downtime, and broader economic impacts, both in the present and in the next 30 years under climate change scenarios. The approach is distinguished by its use of high-resolution flood hazard data, tailored depth-damage functions specific to commercial structures, and integration of economic indicators such as land-use-based economic multipliers.

Xie et al. [45], by contrast, employ spatial-temporal analysis with LiDAR-Based Digital Elevation Model (DEM) and sea-level projections to estimate direct property damages, basing the property value on a GIS map dataset from the Florida Department of Revenue, acknowledging limitations due to the exclusion of indirect costs and valuation uncertainties.

Tu et al. [46] similarly use integrated flood modelling with a construction cost approach, including CBA, to estimate damage and adaptation needs in Shanghai, quantifying building damages and emphasising the exposure of residential assets under extreme flood scenarios. However, as did Xie et al. [45], Tu et al. [46] note challenges with outdated building data and potential inaccuracies in stage-damage functions, underscoring the need for dynamic, high-resolution data in flood cost assessments.

Dolores et al. [40] apply Cost-Revenue Analysis (CRA) with Monte Carlo simulations to evaluate energy retrofits in the Campania region, Italy, finding that while photo-voltaic systems reduce costs modestly, government incentives are critical for financial feasibility, with a high failure probability without support. This mirrors the challenges in other studies (e.g., [55]) regarding dependence on policy incentives for adaptation viability.

He and Faure [54] take a different perspective by employing a law and economics approach, focusing on post-disaster cost management and emphasising the inadequacies of current financial protection systems due to limited insurance coverage and fiscal pressures. Unlike the technical and quantitative models of other studies, they argue for a context-specific mix of risk financing instruments, but note the lack of integration with physical adaptation measures.

Finally, Villalba et al. [25] review MCDM methods for prioritising retrofits under natural hazards, identifying cost minimisation as a key parameter while noting the influence of tax incentives and the challenges of subjectivity and uncertainty in expert-based decisions. Unlike studies using purely quantitative methods (e.g., ANN, Monte Carlo), Villalba et al. [25] highlight that in addition to safety parameters, the vulnerability of buildings to natural hazards also necessitates consideration of economic and social factors, which have been widely explored in numerous studies within her review.

In summary, emerging approaches such as artificial intelligence, simulation-based modelling, and MCDM offer notable advantages by handling large and heterogeneous datasets [89], modelling complex uncertainty and scenario interactions [25], and enhancing predictive accuracy for cost estimation [90]. They also open opportunities to incorporate stakeholder preferences and to support multi-objective optimisation in retrofit decision-making. More recent contributions also explore legal–economic and hybrid frameworks [7,68], broadening the analytical scope by addressing regulatory and policy dimensions of adaptation.

At the same time, key limitations persist: ANN/AI models are data-intensive, computationally demanding, and often opaque (‘black-box’), with performance sensitive to dataset homogeneity and feature selection [89,90]; MCDM applications can be affected by subjectivity in criteria weighting and limited treatment of uncertainty [25]; and simulation/optimisation frameworks typically demand detailed input data and computational resources that are not always available in practice. Regarding readiness for practice, while simplified regression/ANN predictors are increasingly piloted in project settings [90], most advanced AI/MCDM and simulation frameworks remain at an experimental or pilot stage and require further validation and standardisation before widespread deployment in building adaptation planning [47]. Hybrid frameworks linking economic and legal considerations are promising but not yet tested in real-world building adaptation projects. Overall, these approaches are essential to push the boundaries of adaptation economics, but further validation and practical demonstration are required before widespread deployment.

4.4. Role of Economic Assumptions

An important cross-cutting issue in the reviewed studies is the role of economic assumptions, notably time horizons, discount rates, and financial indicators such as NPV, IRR, and PBP. These parameters are central to whether adaptation and retrofit strategies are deemed cost-effective, particularly given their long implementation cycles.

Several studies demonstrate that results are highly sensitive to the assumed discount rate. For example, He et al. [47] applied a 30-year horizon, which reflects the expected lifespan of a building after renovation, with a 3% discount rate, showing that optimal NPV outcomes for energy retrofits are reached at around 40% efficiency improvement, but that higher discount rates would undermine feasibility. Similarly, Semeraro et al. [59] tested 3%, 5%, and 7% discount rates for NbS, considering growth time windows of 5, 10 and 20 years, confirming that long-term benefits diminish quickly under higher rates. At the macro scale, De Ruig et al. [42] analysed flood adaptation over an 80-year horizon and compared 4% and 7% rates, finding that even small differences significantly changed the optimal mix of elevation versus dry-floodproofing. In contrast, Ashrafian [58] used a 60-year horizon but assumed a very high discount rate of 12.3% (from the Central Bank of the Republic of Turkey), which made long-term retrofits appear less viable, underlining how regional financial contexts influence outcomes. Generally, among the reviewed studies, discount rates varied widely—from low social rates of 2–3% commonly applied in European retrofitting assessments [57,74] to 4–7% benchmarks in U.S. flood CBAs [38,42], and up to 8% in China [71] or 12% in Turkey [58]. Such heterogeneity underscores how strongly NPV outcomes depend on discounting assumptions, with lower rates favouring long-term resilience investments and higher ones often undermining their apparent feasibility.

LCC studies show similar variability. Nydahl et al. [77] adopted a 50-year horizon and introduced the SCC as an additional parameter, stressing how climate externalities affect conclusions. Fregonara and Ferrando [79] proposed stochastic annuity methods that incorporate uncertain service lives and discount rates, moving beyond fixed assumptions.

A few papers also stress pairing NPV with IRR/PBP to avoid single-metric bias (e.g., [40]). Taken together, the evidence indicates that lower (≈2–4%) social or public-planning rates tend to favour durable, high-capex adaptations (deep retrofits, NbS, flood defences), whereas higher (≥7–10%) market-oriented rates bias decisions toward short-payback measures.

Overall, this review confirms that discount rates, time horizons, and valuation methods are not neutral parameters but critical assumptions that directly shape conclusions. Transparent reporting and systematic sensitivity analysis—ideally testing both lower “social” and higher “market” discount rates—are essential for ensuring robust and policy-relevant cost assessments of building adaptation.

5. Conclusions

To explore the scientific production on cost assessment methods for climate adaptation in buildings, a keyword-based literature search was conducted between March and June 2025 using the Scopus and Web of Science databases. The search covered peer-reviewed works published between 2019 and 2024. This review primarily benefits policymakers, urban planners, and smart city managers who need robust evidence on the economic viability of climate adaptation measures. It also provides researchers and practitioners with a structured overview of cost-based methods, supporting more transparent, resilient, and investment-ready adaptation planning.

A systematic screening process identified 38 eligible records, which were then classified into three primary methodological clusters: (i) Cost–Benefit Analysis (CBA) methods (15 records), (ii) Life Cycle Costing (LCC) methods (11 records), and (iii) other cost assessment approaches (12 records), including emerging tools such as artificial intelligence, probabilistic modelling, and multi-criteria decision-making.

The first cluster comprises studies employing CBA to evaluate the economic viability of building-level adaptation strategies, with a strong focus on flood-related risks and nature-based solutions. These studies emphasise building-specific assessments and dynamic modelling as best practices under climate uncertainty. Micro-scale, building-specific CBAs have emerged as the best practice for maximising economic efficiency.

The second cluster features applications of LCC to assess long-term cost efficiency of retrofit interventions, often combining it with energy performance modelling or environmental impact metrics. It is particularly valuable for sustainable buildings, where higher upfront costs are often offset by long-term savings in energy and maintenance.

The third cluster gathers diverse, often experimental, approaches such as machine learning, law and economics, or simulation frameworks, offering complementary insights into the cost dimension of building resilience.

From the critical analysis of these studies, several key observations can be made:

• While residential buildings and flood hazards are well represented, other building typologies (e.g., educational, heritage, or mixed-use) and hazards (e.g., wildfires, storms, sea level rise) remain quite underexplored. Future research should expand to capture the diversity of buildings and climate risks across different geographic contexts.
• Although economic methods have advanced significantly, many assessments are still theoretical or scenario-based. Real-world applications, particularly those incorporating actual cost data, stakeholder feedback, and policy mechanisms, are limited. Bridging this gap between research and practice is essential for mainstreaming adaptation planning.
• The cost-effectiveness of NbS is increasingly demonstrated, yet their intangible benefits (e.g., ecosystem services, health co-benefits, equity) are rarely monetised. Developing methodologies to better integrate these aspects into CBA and LCC frameworks will enhance decision-making relevance.
• Despite frequent application of LCC and CBA tools, these are often used ex-post to justify interventions rather than to inform early-stage design. For a transformative shift toward climate-resilient buildings, economic assessments should be integrated from the conceptual design phase, in combination with environmental and social metrics, to enable lifecycle-based decision-making.
• Finally, while many studies recognise the role of public incentives and regulatory frameworks in adaptation financing, few explore their integration in cost analysis. Future work should better align economic assessments with policy tools to improve the feasibility and uptake of resilient solutions.

Taken together, these findings highlight the need for integrated frameworks that move beyond stand-alone methodologies. One promising direction is to link CBA for capturing broader socio-economic impacts, LCC for long-term financial feasibility, and MCDM to incorporate environmental and resilience criteria alongside stakeholder preferences. Recent studies already illustrate parts of this integration, for example, through combining energy simulations with net present value assessments [47], or embedding sustainability and safety criteria into MCDM-based retrofit evaluations [25].

Building on these advances, the next step is to design frameworks where quantitative cost analyses are systematically complemented by participatory weighting of resilience and co-benefits, in line with EU policy frameworks is in line with ongoing EU policy frameworks, such as the EU Taxonomy (2020/852), the recast Energy Performance of Buildings Directive (EPBD IV), and the EU Adaptation Strategy. Such integration would ensure that building adaptation solutions are not only cost-effective but also equitable, transparent, and aligned with long-term climate resilience goals.