The Real-World Use of Building Energy Regulations as a Mechanism to Accelerate Climate Resilience in the Global South

Abstract

International research and policy frameworks underscore the value of mandatory energy regulations in reducing energy demand and greenhouse gas (GHG) emissions in the built environment. However, Global South (GS) countries experience several challenges in effectively implementing building energy efficiency codes (BEECs), as codes are either absent, unevenly adopted or inconsistently enforced. A poor alignment with the specific climatic, socio-economic and construction realities further limits the potential of BEECs to support GS climate resilience. This research aims to identify opportunities to enhance building energy regulatory practices by exploring recent progress in the field. It also systematically evaluates existing mandatory BEECs in the GS to identify models and principles that could guide the development of more effective codes, specifically for GS countries without BEECs. It is hypothesised that the mandatory BEECs currently implemented in GS countries can be analysed using contextually relevant criteria to reveal common regulatory patterns, strengths, and shortcomings, thereby informing a climate-responsive framework suited to GS realities. This research implemented a two-tiered literature review. After determining the broad regulatory context, an exploratory review of the current state of the art in BEEC research was conducted. These publications (primarily 2016–2025) were obtained via a systematic query in Scopus. Following the exploratory review, this study performed a Systematic Quantitative Literature Review (SQLR) to assess mandatory BEECs from 18 GS countries. The findings reveal that BEECs are useful for delivering energy-efficient buildings in the real world. However, ample opportunities exist to improve their comprehensiveness in context and coverage. Improving regulatory implementation systems and structures, along with robust stakeholder engagement, can support better BEEC design and enforcement. To address the need for contextualised BEECs, the SQLR helped develop a taxonomy by comparing the mandatory codes. This research also introduces the Sustainable Level Indicator Model, Matrix, and Map (SLIM³) prototype, proposed as a decision-support tool, and hosted on an interactive online platform, thereby potentially contributing to real-world building energy regulatory practices. The SLIM³ tool organises the mandatory BEECs into a coherent, accessible framework that could assist GS decision-makers in benchmarking existing and new codes, identifying gaps and prioritising contextually appropriate improvements, thus contributing to a more resource-efficient built environment.

1. Introduction

The built environment is a major contributor to climate change, accounting for 30–40% of global energy demand and Carbon Dioxide (CO₂) emissions [1]. Generally, the construction, operation and end-of-life management of buildings are resource-intensive processes that often strain the natural environment and critical infrastructure, such as the energy grid [2,3,4]. This challenge is exacerbated by the growth of the building sector, largely driven by rapidly expanding cities [5]. Global estimates show that the building sector could grow by nearly 70% between 2022 and 2050, from approximately 253 billion m² of built floor area to 291 billion m² by 2030 and 427 billion m² by 2050 [6,7]. A large portion of that growth is expected in the Global South (GS), and the projected GS urban expansion (which is linked directly to population growth) is expected to increase building sector energy consumption and greenhouse gas (GHG) emissions [8,9]. Ultimately, concerted action is needed to ensure a sustainable and climate-resilient built environment.

Building energy efficiency codes (BEECs) are essential regulatory instruments for reducing energy demand and GHG emissions in the built environment [10]. However, the GS mostly lack BEECs, and where policies exist, they remain unevenly adopted, inconsistently enforced, and often do not respond to specific contextual and micro-climatic conditions [11,12]. Although international research and existing policies emphasise the importance of developing contextual energy regulations and codes, GS regulatory frameworks are often informed by the Global North (GN) practices [13]. However, the GN approaches often assume advanced technical and institutional capacity, available economic resources, and formal construction practices [14]. These are not representative of the GS contexts [15,16], further emphasising the knowledge gap. In addition, the misalignment limits the effectiveness of BEECs in the GS as mechanisms for supporting climate resilience in rapidly urbanising regions. For context, the term “Global South” has historically proved difficult to define, especially due to challenges in classifying economic perspectives and geographical delineation. However, the term highlights inequalities and economic indicators that delineate the world into different regions. It originates from the work of Willy Brandt (German Chancellor, 1969–1974) via the Independent Commission on International Development Issues (ICDI) [17]. Brandt led a global panel of experts and politicians to produce the 1980 report North-South: A Programme for Survival [18], also known as the Brandt Report. The Brandt Report divides the world into two concepts, but while the report argued that the “North” and “South” classifications are not a permanent grouping, it identified these classifications as broadly synonymous with “developed” and “developing” [18]. Four decades after the original report, an extensive study by Lees [19] tested the current relevance of the Brandt Line for international relations by using “politically relevant measures of inequality and dissatisfaction”. Despite changes in G77 membership, Lees [19] used the 1980 members as a constant for the GS. On the other hand, the GN comprises “the states that were members of the Organisation for Economic Co-operation and Development (OECD) in 1980”. It could be argued that this methodology ensures replicability by reviewing “… the same groups of states through time …” [19]. Ultimately, the study concluded that the Brandt Line remains an appropriate geopolitical representation of global economic inequality [19], highlighting development opportunities.

Previous reviews have often focused on specific building energy regulation components, such as the requirements and specifications for mechanical heating and cooling equipment [20], building occupants [21,22], indoor environmental performance [23], and passive design measures [24]. Other researchers reviewed broader issues in connection with BEECs, such as life-cycle benefits [25] and energy labelling programmes [26]. Some closely aligned studies are not recent, such as the 2010 publication by Iwaro and Mwasha [27], but these helped build understanding in the field, with the article being highly cited. In addition, reviews focused on specific countries and regions, such as the studies on the United States [28,29], Hong Kong [30,31], and North America [23]. Nevertheless, a real-world perspective on BEEC practices is lacking, especially given the current regulatory landscape.

To address the identified knowledge gap, it is necessary to examine the roles and status of available BEECs in the GS and identify best practices to support the development of contextually appropriate BEECs. The resultant research question is: How can recent research and practice on building energy regulations inform more effective, context-specific codes and accelerate climate resilience, especially in the GS? This study adopts three specific objectives to address this research question. Firstly, it highlights the implementation status of building energy regulations globally, with an emphasis on the state of codes in the GS region. Secondly, it seeks to identify and discuss opportunities which could improve building energy regulatory practices in the real world, based on a review of existing research. Finally, this paper aims to briefly demonstrate an approach that could enhance the contextualisation of BEECs and decision-making, which ultimately helps improve climate resilience in the GS and built environment.

The discussions in this paper are organised in a logical flow using the following structure. Section 2 outlines the methods used to address the objectives of this paper. Section 3 provides further context about the current landscape of building energy regulations in a positional synopsis. Section 4 presents recent studies and globally relevant findings that support improved regulatory practices. Section 5 discusses the development of a novel online platform as a contextualised tool to aid real-world decision-making in the GS, thereby addressing a significant gap in practice. Section 6 concludes the paper and outlines directions for future search.

2. Methods

This study adopts a structured approach using a two-tiered literature review. The paper was executed in three phases, as shown in Figure 1. Phase 1 frames the research context, presenting the role and status of building energy codes in achieving the first objective. Phase 2 conducts an exploratory desk review to achieve objective 2. Furthermore, Phase 3 of the paper unpacks the Systematic Quantitative Literature Review (SQLR) process used to develop the contextualised tool.

2.1. Exploratory Desk Review

The exploratory desk review was employed to develop Section 4 of this paper. Specific phrases that describe BEECs were stringed together to generate a search query in Scopus. The query focused on the publication title to ensure that building energy regulations were a central theme, not merely a contextual concept in the specific paper. After running the search, Scopus identified 128 relevant documents that were published between 1980 and 2026. A few delimitations were selected, including limiting the results to English-language articles. In a 2025 report, the United Nations Environment Programme (UNEP) [1] emphasised the need to update BEECs globally, further claiming that 20% of the existing mandatory BEECs were ratified before 2015. Thus, the search focused on articles published within the past 10 years (i.e., 2015–2026).

The final advanced search query string used in Scopus to identify relevant publications is outlined as follows: TITLE (“building energy regulations” OR “building energy efficiency codes” OR “building energy codes” OR “energy efficiency codes” OR “energy efficiency regulations”) AND PUBYEAR > 2015 AND PUBYEAR < 2026 AND (EXCLUDE (DOCTYPE, “re”) OR LIMIT-TO (DOCTYPE, “ar”) OR LIMIT-TO (DOCTYPE, “cp”)) AND (LIMIT-TO (LANGUAGE, “English”)).

Following the final search query, Scopus identified 83 relevant publications. These papers were manually screened by the researchers to ensure relevance. Each paper’s title, abstract, introduction and conclusion were screened for relevance. This process identified 23 articles as irrelevant or beyond scope, reducing the initial sample to 60 publications. After categorising these studies into themes, the initial sample of papers was later expanded as other studies were identified and pulled into the narrative.

Scopus is a leading research database and has been used across various systematic and bibliometric reviews to identify pertinent literature [32,33]. Many of these studies integrate multiple databases when developing their sample of papers [33,34,35,36]. However, this study used Scopus results because the goal was not to conduct a bibliometric or systematic analysis, but to explore the research landscape within the premise of the paper’s second objective. In addition, published reviews have relied primarily on metadata gathered via the Scopus database [32,37,38,39,40,41,42], demonstrating that it is widely accepted as a comprehensive source. Further work could identify and analyse BEEC research trends using bibliometrics, integrating other databases such as Web of Science.

2.2. Systematic Quantitative Literature Review (SQLR)

During Phase 3 of this study, an SQLR was employed to map policy documents related to building energy regulations in the GS. The findings are synthesised into a structured taxonomy that categorises BEECs according to regulatory type, sectoral application, and implementation approach across the selected GS countries. These categories were derived through a mix of deductive and inductive reasoning. A researcher assessed the documents using typical building energy code classifications (i.e., deductive), and expanded the dataset as additional requirements were identified (i.e., inductive), while another validated the data. According to Thomson et al. [43], an SQLR is useful for conducting a critical examination of specific topics or themes, helping researchers to map existing knowledge domains and identify gaps for further work. This approach fosters objectivity and limits potential bias when assessing the literature [44,45,46]. In addition, an essential element of SQLRs is quantifying and analysing data that is presented in structured formats, such as spreadsheets and tables [47]. These characteristics outline the benefits of deploying this approach to evaluate the specific BEECs used in developing the contextualised tool. Further details are presented in Section 5 and Section 6 of this paper. Ultimately, the SQLR produces a taxonomy that categorises BEECs in the GS, culminating in a comprehensive database. Figure 2 summarises the SQLR and taxonomy in a six-step process.

3. A Positional Synopsis of BEECs: Overview, Role, and Implementation Status

3.1. Brief Overview of Building Energy Regulations

Building regulatory codes form the foundational framework for the planning, construction and occupation of buildings [48]. These regulations typically comprise a series of codes and/or standards that address structural safety, fire protection, health, and building accessibility. Generally, BEECs are integrated into a building regulatory series to guide and regulate the energy performance of buildings, rather than as a standalone instrument [49]. Their origin can be traced back to the 1970s, when energy-related regulations emerged in response to major economic, environmental, and health concerns [50]. Initially, building energy regulations focused solely on reducing household energy costs and on addressing the impact of cold-climate conditions on indoor environments, particularly in Northern Europe and Scandinavia [51]. As a result, early thermal performance requirements and insulation specifications were primarily developed to improve indoor comfort levels and reduce occupant-related health issues [50]. It was only once awareness of global energy consumption and environmental degradation increased that the scope of BEECs expanded significantly. In response, governments often implement BEECs, also referred to as energy standards, energy efficiency codes, thermal building regulations, or energy conservation building codes, as formal legislative tools to regulate building energy use.

Currently, the building sector accounts for about 30–40% of total energy demand and associated GHG emissions. Thus, building energy regulations are critical for prescribing minimum performance requirements for new buildings and, in some cases, for retrofitting the existing building stock [52,53]. Modern BEECs include aspects such as building envelope performance, insulation requirements, heating and cooling loads, lighting power density and overall energy consumption thresholds to ensure energy efficiency [49,54]. In addition, the implementation of building energy regulations offers significant economic and social benefits, such as long-term reduction in energy expenditure, energy security, and improved grid reliability, as well as enhanced indoor thermal comfort and overall health of building occupants [16,55,56]. Other studies argue that the built environment can be one of the largest contributors to decarbonising the global economy [57]. In addition to energy efficiency and reduced energy demand, strategies include reducing material use and promoting the adoption of low-carbon and renewable energy. While stakeholders of the Global Roadmap for Buildings and Construction Report envisage a plausible chance that the built environment can achieve net-zero goals from 2030 onwards, there is strong consensus that regulators need to replace prescriptive-based building energy codes with performance-based regulations for such goals to be achievable [49]. This poses significant challenges, as several countries do not include buildings or the built environment in their nationally determined contributions (NDCs) [49,58]. It is therefore crucial for BEECs to be recognised as an essential policy mechanism for improving the built environment’s overall energy performance, while advancing sustainability and supporting global climate change goals.

3.2. Role and Effectiveness of Building Energy Regulations

The primary objective of BEECs is to prioritise energy efficiency and building performance at the lowest possible cost, while reducing built environment GHG emissions [27,49,59]. However, the development and implementation of energy policies, both nationally and internationally, pose many complex challenges, as policy processes are determined by each country’s technical, institutional, economic, and environmental settings [60]. Overall, the effectiveness of BEECs depends on multiple factors which require substantial consideration before their potential as a real-world energy efficiency mechanism can be realised, including the following:

• The stringency level of the regulations, as more stringent codes can result in higher energy savings and greater emissions reductions;
• The state of compliance with the regulations by design professionals, builders, contractors, and property owners;
• Enforcement channels and mechanisms to drive compliance rates;
• The design of the codes to adequately include contextual issues, such as accurate climate zoning;
• Knowledge and awareness of the regulations, as well as the education and competency of all professionals involved in the building project [61].

Given the differences in the technical, statutory and financial capacities of developed and developing countries, BEEC compliance and enforcement can be challenging [49]. In Section 4, this paper further discusses these issues in greater detail.

3.3. Implementation Status and Lack of BEECs

Over the last two to three decades (i.e., since 2000), the number of countries that formalised and deployed building energy regulations has steadily grown. A 2022 UNEP analysis of the building and construction industry [62] reported that only 79 countries possessed BEECs as either mandatory or voluntary codes. Of these 79 countries, 51 have mandatory codes that cover their entire building sector (i.e., residential and non-residential). While the total number represents a 27% increase from 62 countries over the six years measured (2015–2021) [17], the gap remains significant because most countries have not prioritised BEECs, despite the few that have codes in development. Estimates by the International Energy Agency (IEA) support this claim, stating that mandatory BEECs are non-existent in over 110 countries [63]. This has significant implications for the rapidly expanding built environment. Of the 4.6 billion m² of new residential and non-residential floor space added in 2022 alone [7,64], about 2.4 billion m² was developed with nominal consideration for energy efficiency requirements due to the lack of codes [63]. Although BEECs can serve as a fundamental policy tool, the statistics suggest that regulations often fail to keep pace with the growing building sector and evolving practices. Thus, urgent action is required to establish and implement mandatory building energy regulations globally [65]. This need is particularly acute in the GS region. Although there is a mix of full or partial mandatory BEECs (either compulsory or voluntarily implemented), and some GS countries are at various stages of BEEC development, most GS countries have no known codes. The authors developed Figure 3 to illustrate the implementation status in the GS, with the GN status added for context, using data from an extensive study by Gaum [66] and a UNEP report [67]. The world base map material for Figure 3 (and all other world map-based figures in this paper) was generated using MapChart [68], which is a free, widely used tool for creating custom maps.

It is important to clarify that a country’s mandatory codes do not imply that the regulations are without shortcomings. In other words, there are still opportunities to improve the current BEEC landscape. The following section discusses the pertinent literature that explored these opportunities to enhance building energy regulatory practices.

4. Recent Progress and Opportunities in BEEC Research and Practice

There is a growing concern that the static assumptions embedded in several BEECs do not reflect real-world conditions [69]. Recent research findings highlight the need for a more dynamic, context-based approach when developing BEECs to enhance building energy efficiency. These studies challenge the use of generic requirements and limits and recommend context-specific adjustments to reflect real-world conditions. For instance, the study by Crawford, Bartak, Stephan and Jensen [25] emphasises the need to consider embodied energy when developing BEECs, as material selection can increase a building’s total life-cycle energy demand. Changnawa and Baltazar [70] criticise simplified models, suggesting the integration of Building Information Modelling (BIM) and Visual Programming Language (VPL) with code frameworks for real-world applications. Similarly, O’Brien and Gunay [71] identify significant gaps in how codes consider changing occupancy patterns and behaviours.

In addition, a simulation study of 40 real building cases in Hong Kong, which focused on their Overall Thermal Transfer Value (OTTV), concluded that a single OTTV cannot be universally applied [72]. In the study’s concluding remarks, Chan [72] again highlights the “need to consider the specific energy needs and usage patterns of different types of buildings”. Similarly, a review of building energy code compliance over three decades in the United States indicates the need for further studies focusing on the impact of contextual factors, i.e., climate, building typology and configurations, on BEECs [29]. These examples frame the need for this section’s discussion, which focuses on how BEECs support the delivery of energy-efficient buildings, regulatory compliance issues, and improved BEEC practices.

4.1. Influence of BEECs on Delivering Energy-Efficient Buildings

BEECs are designed to facilitate energy efficiency in buildings. However, the actual energy consumption of buildings during the operational phase can often vary from the expected performance [13]. This phenomenon is referred to as energy performance gaps (EPGs) and has been extensively researched, with various types of EPGs and leading causes identified [73,74,75]. One key EPG category is the regulatory performance gap, which is the variance between the minimum performance targets required to comply with BEECs and the actual energy consumption of buildings [75,76]. This gap raises questions about the design and structure of building energy regulations and their real-world impact on the energy performance of buildings [75,77].

Numerous researchers have explored these questions to determine the impact of building energy regulations. The study by Levinson [78] assessed the energy efficiency gains delivered to California’s new building sector in the United States of America (USA), within the context of the state’s periodically updated BEECs. This assessment was conducted by comparing energy consumption patterns in residential buildings’ pre- and post-codes (i.e., before and after the state’s first BEECs were ratified), in scenarios that vary in energy regulations, exterior conditions (specifically, outdoor temperature) and geographic contexts. Following rigorous analysis, the study concluded that the actual energy savings in new buildings across California were substantially lower than the 80% energy savings expected from compliance with the regulations. The author suggested that the variance exists due to several factors, such as the potential remodelling of buildings that were built pre-codes or an overestimated impact of the codes. Another study arrived at a similar conclusion after evaluating the impact of BEECs on electricity consumption in residential buildings. Using household data from the American Community Survey (ACS), along with a multiple regression and a quasi-experimental observational research approach (i.e., difference-in-differences), Holian [79] estimated that the regulations yielded a 1.5% efficiency improvement in Californian residences and 4% in the USA overall. Several other studies observed a more substantial impact on energy savings as regulations improved, suggesting that the impact of BEECs is context-specific. For example, Zabalza, Gesteira and Uche [10] examined the impact of improving Spain’s building energy regulations, focusing on four iterations of the codes between 1979 and 2019. After analysing over 60 scenarios using building energy simulations, the study found that residences in Spain became substantially less energy-intensive when designed in accordance with the more recent iterations of their energy codes. Specifically, annual heating energy demand reduced by 30–50% with each BEEC iteration, while annual cooling energy demand also decreased by 4–11%. Another study in Morocco found that the thermal load required for space conditioning (i.e., heating and cooling) of a residence was optimised by 17–35% after configuring a residence to meet the insulation requirements of the country’s thermal regulation for construction [80]. These findings underscore the effectiveness of BEECs and highlight the need for ongoing regulatory refinement.

Building energy codes are typically composed of several variables and performance requirements, which align with building components [81,82]. Researchers tend to focus on testing the effect of specific variables and parameters to evaluate the impact of BEECs on building energy performance. For instance, a few studies adopted Thailand’s BEECs as the basis for retrofitting existing buildings to evaluate opportunities for efficiency gains. Notably, Thailand is one of the few countries in the GS that implements mandatory building energy regulations [83]. Focusing on the material specifications and building envelope, Chiradeja and Ngaopitakkul [84] observed that retrofitting a case study educational facility to comply with the codes could yield efficiency gains of up to 65%. Another study retrofitted an existing residence in Thailand to comply with the relevant codes and achieved a 49% energy savings [85]. These findings were supported by Chiradeja et al. [86], who also included lighting and air conditioning requirements in their retrofit strategy. These studies demonstrate that improving the thermal performance of the building envelope, as defined in building energy regulations, enhances energy efficiency.

In addition to heat transfer through the building envelope, water heating accounts for a significant share of energy consumption in buildings [87,88,89,90], sometimes reaching 60% [89]. Historically, deployment of solar water heating solutions increased steadily, largely driven by policy and incentives [91]. Presently, several countries include requirements for water heating systems in their regulations to foster energy efficiency. Belmonte et al. [92] evaluated the feasibility of domestic hot water (DHW) systems in Spain’s residential building sector, weighing energy savings and economic viability through a mix of deterministic and stochastic analyses. The study verified that DHW systems yield energy savings, but the associated capital and operational expenditures result in a solution with limited economic viability. Specifically, it stated that economic feasibility was more likely for residential buildings with more than 48 units, whereas it was not viable for smaller structures with 5 units or fewer. These findings suggest potential challenges in adopting DHW systems, especially in small-scale residences or applications, findings further corroborated by other researchers [93,94,95]. However, others argue that numerous benefits still exist for the entire building sector [91,96]. Nevertheless, these studies offer evidence that spotlights the need for the design and implementation of BEECs to be holistic.

In further support of the findings discussed, research consistently shows that BEECs deliver energy savings across different contexts and time periods. A study based in India examined the impact of the regulations on energy efficiency at a city scale [97]. According to Rajan, Kartikay and Himani [97], large office buildings in the region could achieve 6% savings if their building envelope specifications complied with the regulations. The savings grew to 27% when all measures in the regulations were integrated. Another study in the USA supported this claim, emphasising that the largest savings in small offices could be achieved through better lighting strategies, as demonstrated via various iterations of the American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) 90.1 energy codes [98]. Further examples of the long-term positive impact of BEECs can be found in [99,100].

Notably, energy efficiency achieved through building energy regulations contributes to global energy security. As baseline performance of buildings improves, the sector’s overall demand on existing energy systems can be optimised, further minimising the strain on the energy grid [101,102]. At the building scale, lower energy demand and consumption often lead to lower utility bills, which ultimately reduce energy poverty [103]. However, the effectiveness of BEECs often depends on external factors. Therefore, the following section explores the issues of implementation, compliance, and enforcement of energy regulations.

4.2. Implementation, Compliance, and Enforcement of BEECs

The subject of compliance and enforcement of building energy regulations is a critical issue that researchers continue to explore, given the risk that non-compliance limits the capacity of BEECs to facilitate a sustainable built environment [104,105,106]. Previous studies showed that countries with well-established energy codes, such as England and Wales, struggled with non-compliance in the development of new buildings [107,108]. A review by Lee and Yik [109] argued for structuring BEECs into mandatory and voluntary components to foster building energy efficiency in a cost-effective manner. Presently, the global landscape of building energy regulations has a mix of mandatory and voluntary codes [81,82,83].

According to Yu et al. [110], examining BEEC compliance can lead to greater adoption of energy-efficient technologies and systems, facilitate effective implementation, and drive regulatory enforcement in the building sector. This could also lead to greater innovation in compliance validation systems and support for stakeholders across the value chain, such as developers and regulators [107,111,112]. However, several barriers exist that hinder the application and effectiveness of BEECs in the built environment.

Table 1. Barriers and opportunities in implementing, complying with, and enforcing BEECs.

#	Article Title	PUB Year	Region	Key Findings		Ref.
				Barriers	Opportunities
1	Measures to enforce mandatory civil building energy efficiency codes in China	2016	China	Need for evidence that BEECs lead to actual energy savings to improve the confidence of stakeholders	Innovative financing options to aid retrofits of existing buildings Regular code updates Establishing energy efficiency labelling systems for buildings Supervision procedures to ensure compliance and quality control Annual verification of actual energy efficiency levels Incorporating compliance rates as a key data metric for monitoring and evaluation by local municipalities	[113]
2	An international survey of building energy codes and their implementation	2017	22 countries	Local compliance verification authorities often lack sufficient capacity	Capacity building training for code enforcement personnel Technical manuals and resources to facilitate accurate knowledge of the codes among stakeholders Well-designed penalties and incentives for enforcement Catalogue of tested and validated building materials, made accessible to developers and regulators	[11]
3	The cost of enforcing building energy codes: an examination of traditional and alternative enforcement processes	2017	United States of America	Operational costs associated with enforcing BEECs can be substantial when accounting for the volume of buildings	Capacity building training Performance validation and verification	[114]
4	The international implications of national and local coordination on building energy codes: Case studies in six cities	2018	Colombia, Vietnam, Turkey, Mexico, India, South Africa	Inadequate funds and resources to drive the implementation of BEECs Limited compliance evaluation due to low capacity Absence of incentives for buildings to exceed minimum performance requirements	Enhance the coordination between the regulatory authorities at the national and local levels for better implementation of codes Engage all relevant stakeholders when developing BEECs Capacity development and training Penalties such as fines and licence suspension for non-compliance	[115]
5	Evaluating Building Energy Code compliance and savings potential through large-scale simulation with models inferred by field data	2020	United States of America	Verification of compliance is challenging, considering the limited opportunity afforded to visit buildings individually for the purpose of conducting the assessment		[116]
6	Barriers, drivers and prospects of the energy efficiency code in the Lagos real estate market	2020	Nigeria	Scepticism among professionals about the feasibility of timelines expected for implementation New leadership in the political sphere resisting the implementation of previous policies	Improve engagement with stakeholders, including regulators, practitioners, and building clients for concerted action	[117]
7	Review of Building Energy Code and its implementation in residential sector: A global outlook	2021	12 countries	Absence of penalties for non-compliance	Building energy efficiency labelling Policies to encourage retrofit Penalties that relate to non-compliance can be structured at local levels Potential for construction permit denial as a penalty for non-compliance Resource materials that educate and guide users on energy codes compliance Creation of new software tools or platforms to aid compliance evaluation and reporting	[118]
8	A cooperative federalism model for building energy codes	2021	United States of America	Presence of BEECs at the state levels is inconsistent Lack of recent updates across many localised building energy regulations	Endorse existing regulations that are proven Introduce new codes at a national level and update them in three-year cycles Local regulators contextualise the national codes for implementation in specific region Increase support for compliance assessors and funding for local regulatory authorities Invest in capacity development training and take advantage of existing resources Encourage knowledge sharing across regions to scale up effective best practices	[119]
9	Compliance with Building Energy Code for the residential sector in Egyptian hot-arid climate: Potential impact, difficulties, and further Improvements	2022	Egypt	Lack of legislative structure for enforcement and compliance evaluation Limited awareness and value for the role and impact of energy-efficient buildings among homeowners and industry professionals	Drive retrofit of existing residential buildings Motivate for government involvement and investment in fostering an enabling environment Periodically update BEECs and provide sufficient support for building owners to adopt the transition Capacity development training Raise awareness through strategic engagement with stakeholders	[120]
10	What, why and when to go virtual: An international analysis of early adopters of virtual building energy codes inspections	2022	Australia, Canada, Singapore, United Arab Emirates, United States of America	Physical inspections of buildings to evaluate compliance are often resource-intensive and susceptible to human oversight Adopting virtual inspections poses technological, cost, and data privacy challenges	Virtual inspections for building energy code compliance evaluation can help improve the efficiency of regulators, especially in regions with high construction activity	[121]
11	Building Energy Codes compliance: Practices around the world	2023	Global	Typical code compliance verification procedures can be complex and time-consuming	Capacity development training Develop new or improved accreditation systems for energy code compliance officers Encourage BEEC research collaboration across geographic contexts to foster knowledge sharing and the transfer of best practices	[122]
12	Conceptual cross-theoretical assessment model for practitioners’ compliance behaviour with Building Energy Codes	2024	Not specified	The psychological disposition of building professionals towards BEECs and energy efficiency influences compliance behaviour and design practices	Regulatory authorities can be more intentional in designing policies that incentivise better compliance practices and higher performing buildings	[123]
13	Towards effective implementation of Building Energy Efficiency Codes in Tripoli, Lebanon: Key actions for enforcement	2024	Lebanon, India, United States of America, Germany	Inadequate funding, resources, support, and compliance evaluation systems and infrastructure	Establish regional and local technical teams to aid the enforcement of codes Engage third-party organisations or personnel for compliance inspections in a structured approach Improve the compliance architecture of the codes from prescriptive to hybrid and performance-based Periodically conduct unscheduled code compliance audits Well-designed penalties and incentives to reduce non-compliance and foster better-performing buildings Enhance stakeholders’ awareness of the benefits of BEECs through strategic engagement	[12]

summarises 13 global studies similarly outlining several of these barriers. It also enumerates numerous opportunities to improve the implementation and enforcement of building energy regulations.

Ultimately, the barriers and opportunities presented in Table 1 can be categorised into three essential factors that influence the effectiveness of BEECs:

• Systems: This refers to the processes that are instituted to facilitate implementation and enforcement of BEECs and the actions that are necessary to support the processes, such as providing funding to support the operational costs of compliance evaluation [119], and the acquisition and upskilling of additional personnel to improve the capacity for inspections [11,122].
• Structure: This outlines the levers that are in place to stimulate and sustain implementation and compliance, including the use of incentives and penalties [12,123], as well as timely updates to the regulations [120].
• Stakeholders: These are the key actors involved in the delivery of compliant, energy-efficient buildings, including building owners, professionals, compliance auditors, and regulators, each with their own roles, unique experiences, and needs [117,123].

The strategic consolidation of these essential factors can help address non-compliance with building energy regulations. However, these enablers may become unproductive if the core design and components of the codes being implemented are inadequate, incomprehensive, and non-contextualised.

4.3. Innovation in the Design of Building Energy Regulations Towards Improved Practices

As adverse global climatic conditions continue to intensify, the design of building energy codes is becoming increasingly important [124]. This section explores various studies that outline avenues to enhance BEECs for the delivery of energy-efficient and resilient buildings. The discussions are grouped into two innovation pathways, as described hereafter.

4.3.1. Path I: Expanding the Scope and Methods of BEECs

Building energy regulations around the world vary considerably in scope and approach (i.e., how building energy performance is analysed) [82]. This variance in development levels is more pronounced when comparing the codes across the GN and GS countries [81]. Research is currently ongoing to address this gap in practice and develop more comprehensive codes. These studies typically focus on specific components with the potential to yield overall benefits.

One key component that structures how BEECs are applied in building design is the climate zoning or classifications within the regulations [125,126]. However, researchers argue that there is limited consensus on the processes and methods for defining climate zones in BEECs [126,127]. The study by Mazzaferro et al. [128] built on this discussion, attempting to demonstrate the importance of building performance data for defining climate zones in codes using data from 8,631 energy performance simulations and 21 office design variations across 411 cities in Brazil and eight bioclimatic regions. The study concluded that conventional climate zoning methods (often organised around climate-specific design principles) are insufficient. It proposed a decision tree approach that achieved improved accuracy, especially for codes that target specific building typologies [128]. The impact of accurate climate zoning in BEECs is substantial and updates need to be approached with a thorough understanding of the scope of its impact [129,130], especially when such changes could lead to unintended consequences, such as lower-performing buildings [131]. Furthering the work on climate-related considerations, researchers also investigate future climate scenarios vis-à-vis their impact on the design and performance of building energy regulations. Initial findings from studies of the regulatory contexts of Saudi Arabia [132] and Brazil [133] suggest that the effects of global warming may necessitate revisions to specifications such as cooling energy requirements and thermal performance material choices.

Another study in Palestine compared the impact of building envelope design requirements in its energy regulations with regional and international regulations [134]. Using DesignBuilder simulations, Haj Hussein, Monna, Abdallah, Juaidi and Albatayneh [134] identified the potential for an additional 40% energy savings when better envelope requirements were implemented. The findings suggest that benchmarking codes against international practices can provide practitioners with temporary guidance for better design and ultimately lead to improved regulatory practices, especially in countries where codes are rarely updated or absent. Kim et al. [135] adopted a different approach, focusing on the energy and cost savings’ impacts on public and private buildings from implementing prescriptive criteria or conducting a rational assessment (i.e., a performance-based method) based on Korea’s building energy regulations. This approach led to several recommendations, including improving window U-values, adopting more efficient heating equipment, and scaling up renewable energy use.

Similar studies that focused on other components, such as lighting [136] and the use of solar photovoltaics (PV) [137], further validate the necessity of updates to building energy regulations. Such improvements, along with the effective support systems, can potentially help practitioners improve their workflows [70] and drive greater compliance with energy codes [108,138]. In essence, the outcomes of these studies demonstrate that expanding the scope of building energy regulations and improving their procedures can foster energy efficiency in the built environment.

4.3.2. Path II: Extending the Strategic Role of BEECs

Building energy codes typically prescribe minimum energy performance requirements for different building types [59,139]. However, considering the negative impact of climate change and the building sector’s potential as a catalyst for climate resilience [140], some studies have explored how BEECs can serve as tools for advancing other ideals such as net-zero goals. After analysing the building energy regulations of five European countries (Denmark, England, France, Sweden, and Switzerland), Schwarz et al. [141] determined that BEECs can be designed to support building sector decarbonisation. The study recommended that regulators integrate requirements that aim to reduce building energy performance gaps, expedite building retrofits, and factors in embodied energy, in addition to the existing requirements for enhancing building energy efficiency and adopting renewable energy systems. Similarly, Hu and Qiu [142] compared the codes of China, Germany, and the USA to examine their capacity to support net-zero goals in the building sector. The study’s findings show that well-designed codes can foster building decarbonisation through a mix of strict and flexible codes (such as the mix of China’s mandatory and flexible standards highlighted in Zheng et al. [143]), as well as innovative requirements. For example, a systematic review by Sadevi and Agrawal [144] argued that shading the non-transparent building elements, such as walls, could yield significant cooling load savings, up to 77% in the reviewed studies. After evaluating several energy codes, the study found that only India and Australia incorporate this requirement, albeit in a limited state [144].

Another study in Hong Kong suggested using innovative PV glazing to reduce heat ingress into the building [145]. Given energy efficiency improvements of 13–39%, the study recommended integrating it into the region’s energy codes. Building on the code of practice OTTV system in Hong Kong, Chen et al. [146] also recommended that radiative sky cooling requirements as a passive cooling strategy can be included in the country’s building energy codes, after observing 73–91% operational energy savings [146]. Further investigation by various studies also highlights additional levers to develop more comprehensive BEECs and potentially support building decarbonisation, such as occupancy-based controls for heating, ventilation, and air conditioning (HVAC) systems [147], and GHG emissions accounting [148].

As a climate change mitigation strategy, building energy codes are typically framed to optimise operational energy. Nevertheless, it is well established that the embodied energy of buildings, along with related GHG emissions, often accounts for a larger percentage of the building’s life-cycle energy use as operational energy consumption becomes more efficient [149,150]. Researchers are investigating various avenues to reduce the embodied impact of buildings, such as using sustainable low-carbon materials [74,151]. However, BEECs as a foundation for efficient practices in the built environment can be expanded to incorporate life-cycle energy use considerations.

To explore this assertion, Stephan and Crawford [152] evaluated the impact of floor area size on life-cycle energy use and its consequences for redesigning BEECs in Australia. After analysing 90 residences ranging from 100 m² to 392 m², the researchers concluded that larger residential buildings appear to be more energy-efficient despite consuming more energy for similar household occupant sizes. One main reason is that energy codes typically adopt energy use intensities (i.e., unit energy per m²) to describe their requirements. The study argues that this approach benefits buildings with a larger footprint, while the additional material used in the construction of larger residential buildings also results in higher embodied emissions [152]. In this scenario, adopting life-cycle perspectives in BEECs could help provide a more holistic assessment of the energy performance of new buildings. Alternatively, a recent city-wide study in China concluded that renovating existing buildings could be a more pragmatic approach to achieving building sector decarbonisation than developing new and efficient buildings with lower embodied emissions [153]. Such changes would require updates to building energy regulations and active stakeholder involvement. Further work on the intersection of life-cycle energy, net-zero goals, and BEEC design can be found in [10,85,154,155]. Ultimately, these studies demonstrate that there are several opportunities to transform the focus of building energy regulations from prescribing minimum building energy performance requirements to being a comprehensive tool for improving building design and development practices.

4.4. The Need for Contextually Appropriate BEECs

The unique socio-economic conditions of the GS warrant the development of contextually appropriate BEECs that also reflect their distinct climate, as established by the preceding discussions. While some GS countries do have BEECs, there remain areas for improvement, such as broader adoption, more extensive coverage and revisions to ensure the development of sustainable energy pathways in the built environment [56,83]. This is particularly important considering that over 70% of the growth in global built floor space constructed between 2010 and 2022 was recorded in low- and middle-income countries (i.e., the GS) [64]. Therefore, the need to accommodate the rapidly growing building sector while reducing energy consumption and improving overall comfort, particularly in the GS, calls for immediate action and the introduction of comprehensive measures.

To achieve long-term transformation in the GS building sector, policymakers, governments, non-state stakeholders, and other key actors need to collaboratively develop and expand energy efficiency policies [156], while strengthening BEECs and enforcing mandatory compliance. Some studies tend to compare BEECs across geographic contexts to improve practices, such as Merini et al. [157] and Merini et al. [158] juxtaposing Morocco and Spain. However, simply importing the established GN strategies to the GS could prove inadequate [15]. As an alternative approach, the existing knowledge and practices of GS countries with compulsory BEECs can be harnessed to develop contextually appropriate BEECs. To demonstrate this approach and address the knowledge and practice gap, this paper presents the development of a contextualised tool that culminates in a comprehensive online database. The tool could potentially help GS countries develop their BEECs to foster sustainable building development, reduce resource consumption and mitigate climate change vulnerability.

5. Developing a Contextualised Tool

This section discusses the development of an interactive online platform, namely, the Sustainable Level Indicator Model, Matrix, and Maps (SLIM³). This platform is a contextualised tool that uses mandatory building energy regulations for whole building sectors in the GS to address a significant gap in practice, as discussed in Section 4. While the tool is in the prototyping and development phase, it already provides practitioners, researchers and regulators in regions that lack BEECs with data that could help inform design decisions. To scope an appropriate context for the analysis, the research first determined the major GS role players. Thereafter, the SLIM³ is presented, highlighting the various steps that users can take to find context-specific recommendations to enhance building energy efficiency.

5.1. The Major GS Role Players

5.1.1. Projected 2050 Urban Population

It is well established in the existing literature that a rising urban population often lead to greater energy consumption, more GHG emissions and an increased impact on climate change [159,160]. In the GS, 45 countries are projected to have urban populations of 20 million or more in 2050 [161].

Table 2. GS countries with a projected 2050 urban population of ≥ 20 million, based on World Bank data [66,161].

#	Country	Region	Income Status	2050 Urban Pop. (Million)	% of the GS	% of the World
1	China	East Asia	Upper middle	1086.62	20.30%	16.52%
2	India	South Asia	Lower middle	866.16	16.18%	13.17%
3	Nigeria	West Africa	Lower middle	280.61	5.24%	4.27%
4	Indonesia	East Asia	Lower middle	240.92	4.50%	3.66%
5	Brazil	South America	Upper middle	211.64	3.95%	3.22%
6	Pakistan	South Asia	Lower middle	176.45	3.30%	2.68%
7	Mexico	Central America	Upper middle	136.86	2.56%	2.08%
8	Congo (DRC)	East Africa	Low income	124.07	2.32%	1.89%
9	Bangladesh	Asia, South	Lower middle	112.38	2.10%	1.71%
10	Philippines	East Asia	Lower middle	89.26	1.67%	1.36%
11	Egypt	North Africa	Lower middle	88.95	1.66%	1.35%
12	Iran (Isl Rep)	South Asia	Lower middle	88.65	1.66%	1.35%
13	Turkey	Western Asia	Upper middle	83.49	1.56%	1.27%
14	Ethiopia	East Africa	Low income	80.22	1.50%	1.22%
15	Tanzania	East Africa	Lower middle	71.72	1.34%	1.09%
16	Vietnam		Lower middle	62.83	1.17%	0.96%
17	Angola	Southern Africa	Lower middle	62.24	1.16%	0.95%
18	South Africa	Southern Africa	Upper middle	60.26	1.13%	0.92%
19	Iraq	Western Asia	Upper middle	57.07	1.07%	0.87%
20	Argentina	South America	Upper middle	52.34	0.98%	0.80%
21	Algeria	North Africa	Lower middle	51.48	0.96%	0.78%
22	Colombia	South America	Upper middle	49.72	0.93%	0.76%
23	Thailand	East Asia	Upper middle	45.8	0.86%	0.70%
24	Sudan	North Africa	Low income	42.69	0.80%	0.65%
25	Kenya	East Africa	Lower middle	42.38	0.79%	0.64%
26	Saudi Arabia	Western Asia	High income	40.26	0.75%	0.61%
27	Uganda	East Africa	Low income	39.49	0.74%	0.60%
28	Ghana	West Africa	Lower middle	38.06	0.71%	0.58%
29	Cameroon	Central Africa	Lower middle	36.97	0.69%	0.56%
30	Mozambique	Southern Africa	Low income	36.11	0.67%	0.55%
31	Morocco	North Africa	Lower middle	35.65	0.67%	0.54%
32	Malaysia	East Asia	Upper middle	35.41	0.66%	0.54%
33	Peru	South America	Upper middle	34.6	0.65%	0.53%
34	Côte d’Ivoire	West Africa	Lower middle	34.57	0.65%	0.53%
35	Venezuela	South America	Not classified	34.01	0.64%	0.52%
36	Madagascar	East Africa	Low income	31.3	0.58%	0.48%
37	Myanmar	East Asia	Lower middle	29.34	0.55%	0.45%
38	Mali	West Africa	Low income	27.55	0.51%	0.42%
39	Yemen	Western Asia	Low income	27.5	0.51%	0.42%
40	Afghanistan	South Asia	Low income	26.63	0.50%	0.40%
41	Zambia	Southern Africa	Lower middle	24.4	0.46%	0.37%
42	Syria	Western Asia	Low income	23.83	0.45%	0.36%
43	Somalia	East Africa	Low income	22.27	0.42%	0.34%
44	Burkina Faso	West Africa	Low income	21.79	0.41%	0.33%
45	Senegal	West Africa	Lower middle	21.4	0.40%	0.33%
Total selected countries:				4885.96	91.30%	74.30%
Global South total:				5351.62
World total:				6576.22

lists the 45 GS countries, along with their respective regions, income status, and projected urban population for 2050. Based on the data, the urban centres of these 45 GS countries are expected to accommodate approximately 91.3% of the projected 2050 GS population and 74.3% of the projected global urban population by 2050 [83,161].

5.1.2. GHG Emissions in the GS

Given the relationship between GHG emission rates and climate change, the second selection criterion is CO₂-eq emissions.

Table 3. GHG emissions in the top 45 GS countries, based on the UNFCCC data [66,162].

#	Country	Region	Income Status	GHG Emissions (Gg CO2-eq)	% of the GS	% of the World
1	China	East Asia	Upper middle	12,300,200	49.22%	28.73%
2	India	South Asia	Lower middle	2,839,425	11.36%	6.63%
3	Brazil	South America	Upper middle	1,014,702	4.06%	2.37%
4	Mexico	Central America	Upper middle	605,887	2.42%	1.42%
5	Indonesia	East Asia	Lower middle	554,334	2.22%	1.29%
6	Saudi Arabia	Western Asia	High income	548,263	2.19%	1.28%
7	Turkey	Western Asia	Upper middle	522,477	2.09%	1.22%
8	Iran (Isl Rep)	South Asia	Lower middle	483,669	1.94%	1.13%
9	Pakistan	South Asia	Lower middle	394,583	1.58%	0.92%
10	South Africa	Southern Africa	Upper middle	379,837	1.52%	0.89%
11	Argentina	South America	Upper middle	338,963	1.36%	0.79%
12	Thailand	East Asia	Upper middle	318,661	1.28%	0.74%
13	Malaysia	East Asia	Upper middle	287,740	1.15%	0.67%
14	Viet Nam	East Asia	Lower middle	278,442	1.11%	0.65%
15	Côte d’Ivoire	West Africa	Lower middle	271,198	1.09%	0.63%
16	Egypt	North Africa	Lower middle	241,632	0.97%	0.56%
17	Nigeria	West Africa	Lower middle	212,444	0.85%	0.50%
18	United Arab Emirates (UAE) *	Western Asia	High income	199,879	0.80%	0.47%
19	Venezuela	South America	Not classified	192,192	0.77%	0.45%
20	Colombia	South America	Upper middle	153,885	0.62%	0.36%
21	Philippines	East Asia	Lower middle	126,879	0.51%	0.30%
22	Chile *	South America	High income	112,001	0.45%	0.26%
23	Algeria	North Africa	Lower middle	111,023	0.44%	0.26%
24	Bangladesh	South Asia	Lower middle	99,442	0.40%	0.23%
25	Morocco	North Africa	Lower middle	96,108	0.38%	0.22%
26	Ethiopia	Africa, East	Low income	94,996	0.38%	0.22%
27	Korea, DPR (N) *	East Asia	Low income	87,330	0.35%	0.20%
28	Kuwait *	Western Asia	High income	86,337	0.35%	0.20%
29	Peru	South America	Upper middle	84,564	0.34%	0.20%
30	Libya *	North Africa	Upper middle	82,129	0.33%	0.19%
31	Syrian Arab Rep.	Western Asia	Low income	79,216	0.32%	0.19%
32	Iraq	Western Asia	Upper middle	72,658	0.29%	0.17%
33	Sudan	North Africa	Low income	67,840	0.27%	0.16%
34	Angola	Southern Africa	Lower middle	61,611	0.25%	0.14%
35	Qatar *	Western Asia	High income	61,593	0.25%	0.14%
36	Ecuador *	South America	Upper middle	60,192	0.24%	0.14%
37	Somalia	East Africa	Low income	53,700	0.21%	0.13%
38	Mali	West Africa	Low income	52,733	0.21%	0.12%
39	Kenya	Africa, East	Lower middle	49,964	0.20%	0.12%
40	Singapore *	East Asia	High income	48,334	0.19%	0.11%
41	Guinea *	West Africa	Low income	47,713	0.19%	0.11%
42	Congo, DR	East Africa	Low income	45,999	0.18%	0.11%
43	Bolivia *	South America	Lower middle	43,665	0.17%	0.10%
44	Afghanistan	South Asia	Low income	43,228	0.17%	0.10%
45	Tanzania	East Africa	Lower middle	39,237	0.16%	0.09%
Total selected countries:				23,946,901.86	98.82%	55.93%
Global South total:				24,992,198.26
World total:				42,818,868.47

* Countries with a projected 2050 urban population of less than 20 million.

ranks the 45 GS countries from the highest to the lowest CO₂-eq emissions, alongside their regional classification, income level, and percentage contributions to emissions in the GS and the world. To further classify the target population for the SLIM³ analysis, the 45 GS countries with the highest CO₂-eq emissions (N²) were compared to the 45 GS countries previously identified as having the largest projected 2050 urban population (N¹). Among the top GHG emitters, ten GS countries have a projected 2050 urban population of less than 20 million. However, given their significant contribution to GHG emissions in the GS, these ten countries were added to the previously identified 45 countries (see Section 5.1.1) to establish the target population.

Including the outliers increased the target population from 45 to 55 GS countries (N²). The target population for the tool now represents 40.74% of the study’s total population (135 GS countries). Furthermore, the total of 55 GS-selected countries represents nearly 93.5% of the GS population (135 countries) and roughly 76% of the world’s projected 2050 urban population. In addition, the identified GS countries (55) make up almost 96.8% of GHG emissions in the GS and approximately 56.5% of the world’s GHG emissions [66,162].

5.2. Climatic Zones Across the Target Population

Climatic regions in the GS exhibit distinctive weather patterns and varying climate conditions compared to those in the GN. The literature review highlighted the unique relationship between climatic regions and extreme weather events in the GS. The Köppen–Geiger climate classification system is a visualisation map widely used by researchers across various disciplines and was used to assess the climate zones of the 55 GS countries. This was performed to ensure the target population represented all climatic zones and to illustrate their vulnerability to the impact of climate change.

Figure 4 presents a newly developed depiction of the Köppen–Geiger climate classification system with an updated Brandt Line [66,163], to provide a detailed overview of the climatic datasets of the 55 GS countries. It is evident from Figure 4 that the sample population (55) includes the five major climate zones and 29 out of the possible 31 climate classes [164,165]. The Dfd and Dsd climate classes do not apply to the GS and were excluded because these two classes occur only in Antarctica, Greenland and the farthest parts of northern Russia. The map further indicates that most GS countries share similar climatic zones and classes (equatorial, arid and warm temperate), except for parts of China and South America that include “snow” and “polar” climate zones.

6. Overview of the SLIM³ Tool

The literature and desk review on the BEECs of 55 GS countries identified several gaps in the development and implementation of climate change policies in the built environment. To address the identified gaps, the researchers selected GS countries with full, mandatory BEECs across their entire building sectors as the sample population. As a result, the sample population (18 GS countries with 20 BEECs) formed the basis for developing a comparative framework.

The analysis of the 20 GS BEECs, together with the conceptual development of the SLI Model, SLI Matrix, and SLI Map, serves as a baseline for prototyping the SLIM³. The SLIM³ functions as a pragmatic decision-making tool, translating energy efficiency data from GS BEECs to a structured framework that can inform policy development and climate strategies, and serve as guidelines for countries without the necessary building energy regulations.

6.1. The SLI Matrix

A comparative analysis of the 20 BEECs from 18 GS countries was conducted to evaluate the presence and structure of energy efficiency criteria across the codes. The results were organised into a comparative SLI Matrix to provide an overview of the technical requirements contained within each BEEC.

In Figure 5, the SLI Matrix lists 20 primary energy efficiency criteria derived from the BEECs and is represented on the X-axis (labelled A-T). The countries included in the sample population are depicted on the Y-axis as numbers 1–18. Where a country’s BEEC addresses a particular criterion or related information, it is indicated with an “X”. Figure 5, therefore, serves as a comparative checklist for identifying countries with specific energy efficiency requirements in their BEECs.

The SLI Matrix was further developed to identify specific regulatory values and quantitative technical requirements within each BEEC. This provided a structured dataset for identifying patterns, similarities, and gaps across the GS, informing the development of the SLI Map.

6.2. The SLI Map

Given the need for clarity and accessibility to data, the quantitative energy efficiency criteria identified through the SLI Matrix were further developed to collate the data into a visual SLI Map.

The geographical representation of findings enables the user to analyse and interpret the data within a spatial context. It further allows the reader to identify regional patterns, climatic conditions, and prescribed energy efficiency requirements included in the identified GS BEECs. The SLI Map (Figure 6) provides a geographical overview of the GS regulatory landscape and summarises the analysis of 18 GS countries with mandatory BEECs. Together, the SLI Model, Matrix, and Map form the foundation for the development of the SLIM³ decision-making tool.

6.3. SLIM³ Tool Synopsis and User Interface

The SLIM³ is still in its development phase, operating on predefined filtering levels that provide users with a high-level overview of BEECs in the GS, as well as customisable user filters to provide context-specific, detailed technical requirements. Details regarding the model structure and analysis method (i.e., the Sheridan, Visscher and Meijer framework, the Nordic Five-Level Model, and the Hierarchy of Built Elements framework) are discussed in the authors’ previous work [163]. Ultimately, this prototype tool includes general information on each country’s regulatory framework, including the country name, region, BEEC title, year, document length, language, and governing authority. The interface operates through the following four developmental stages, guiding the user through the dataset and contextual BEECs.

• Stage one (BEEC Status)

The first filter level provides information on the BEEC status across GS countries, indicating whether regulations are mandatory, partially implemented, voluntary, under development, or none are available.

• Stage two (Climatic Classification)

The second filter level uses the climatic conditions defined by the Köppen–Geiger climate classification system to identify similarities between GS countries. This allows users to filter according to climatic characteristics of their location and facilitates comparisons between regulatory approaches.

• Stage three (Energy Efficiency Criteria)

In the third filter level, users can now select the following hierarchical levels (levels 1–4): whole building, systems, sub-systems, and individual building elements to delineate specific criteria. This allows the user to identify other GS counties that share similar energy efficiency criteria.

• Stage four (Quantitative Energy Efficiency Values)

The final filter level provides access to detailed quantitative energy efficiency data, including specific regulatory values for each BEEC. The tool allows users to compare requirements and examine the range of values specified in the respective BEECs of the GS countries.

The filtering levels can be used to identify both the presence and absence of BEECs, as well as specific energy efficiency criteria within existing codes. The SLIM³ prototype tool is developed to prioritise simplicity, usability, and accessibility. The tool allows users to obtain a comprehensive dataset of contextually specific information for developing BEECs in the GS.

Additional information on the SLIM³ prototype is available at https://becgs.co.za (accessed on 5 March 2026).

6.4. Addressing the Need for Contextualised BEECs

Through the development of the SLI Model, Matrix, and Map, and their integration into the SLIM³ tool, this study aims to address the urgent need for contextualised building energy regulations in the GS. The translation of comparative regulatory data into a single accessible decision-making platform supports global sustainability initiatives and helps GS countries improve climate resilience.

Most importantly, the SLIM³ provides contextually appropriate guidance for developing or strengthening BEECs in the GS by providing a comparative dataset that is easily accessible, economically appropriate, and socially achievable. Lastly, SLIM³ aims to support knowledge exchange and collaborative learning among GS countries, thereby advancing energy-efficient, climate-responsive building regulations.

7. Conclusions and Future Directions

The paper examined the role of BEECs in promoting climate resilience in the GS built environment. The central problem addressed in this research is that BEECs in the GS are either absent or, where present, they are unevenly adopted, inconsistently enforced, and poorly aligned with local climatic conditions, socio-economic realities, and construction practices. These shortcomings limit the potential of BEECs in the GS’s built environment to address resource consumption effectively and build climate resilience amid rapid urban expansion and rising vulnerability to climate change impacts.

The research method consisted of several phases, including an exploratory review of BEEC research and an SQLR of policy sources. A BEEC taxonomy was formulated based on the regulatory type, sectoral application, implementation approach and climatic relevance. This taxonomy supported a comparative evaluation of mandatory codes in 18 GS countries and informed the development of the Sustainable Level Indicator Model, Matrix, and Map (SLIM³). The SLIM³ is a practical decision-making prototype that was developed to suit the unique contexts of the GS countries.

Building energy regulations are designed to prescribe minimum performance requirements. These requirements are both crucial and beneficial for climate resilience, especially given the rapidly expanding global building sector. Their impact could be further enhanced by scaling up implementation, especially in developing economies where the sector’s growth is the largest. The study highlights the need for urgent action to inform and enhance building energy regulatory practices. More notably, it outlines several opportunities to achieve this goal. Countries can strengthen regulatory systems by developing procedures to enforce and verify compliance. However, some GS countries may lack the needed systemic and economic capacity to drive such initiatives. This creates opportunities for stronger intra- and inter-regional partnerships and collaborations. Another opportunity lies in redesigning existing building energy codes. The study outlines two paths which countries can follow. The scope of existing codes can be expanded to prescribe additional whole-building design and performance requirements. In this scenario, well-formulated penalties for non-compliance and incentives for retrofits or buildings that perform beyond the minimum requirements can help catalyse better dispositions and behavioural shifts among building owners and developers. In addition, GS countries can take advantage of the second path by reshaping the role of their BEECs as tools for global sustainability. By integrating strategic goals such as net-zero energy and emissions, countries can foster an energy-efficient building sector while decarbonising their economies and improving their position as key global actors.

Furthermore, the study presents a unique opportunity for GS countries to learn from one another, particularly regions that have not introduced or revised their BEECs. By facilitating knowledge sharing and comparative learning across GS countries, SLIM³ has the potential to bridge current implementation divides, accelerate the adoption of more effective regulations, and contribute to broader GS climate resilience goals in rapidly urbanising regions. The SLIM³ prototype tool, hosted on an interactive online platform, organises these findings into an accessible framework. The effective use of SLIM³ could help policymakers and practitioners benchmark existing codes against contextually relevant criteria. It prioritises requirements that are achievable and economically viable within GS constraints.

Future research should pursue three main directions. Firstly, the SLIM³ prototype requires iterative testing and refinement through application in diverse GS contexts. This should include validation workshops with policymakers, regulators, built environment practitioners, and contractors. Secondly, empirical GS field studies are needed to quantify real-world performance gaps when existing BEECs are implemented. Thirdly, longitudinal studies can examine the impact of contextually relevant BEECs on a larger scale, including urban energy consumption, reduced embodied carbon and GHG emissions and the built environment’s resilience to extreme weather events.