Evaluation of Impacts and Sustainability Indicators of Construction in Prefabricated Concrete Houses in Ecuador

Abstract

The construction of prefabricated concrete houses in Ecuador poses significant challenges in terms of environmental and social sustainability, amid growing housing demand and the urgent need to mitigate adverse impacts associated with the construction processes and materials. In particular, the lack of a comprehensive assessment of these impacts limits the development of effective strategies to improve the sustainability of the sector. In addition, in rural areas, the design of flexible and adapted solutions is required, as evidenced by recent studies in the Andean area. This study conducts a comprehensive assessment of the impacts and sustainability indicators for prefabricated concrete houses, employing international certification systems such as LEED, BREEAM, and VERDE, to validate various relevant environmental and social indicators. The methodology used is the Hierarchical Analytical Process (AHP), which facilitates the prioritization of impacts through paired comparisons, establishing priorities for decision-making. Hydrological, soil, faunal, floral, and socioeconomic aspects are evaluated in a regional context. The results reveal that the most critical environmental impacts in Ecuador are climate change (28.77%), water depletion (13.73%) and loss of human health (19.17%), generation of non-hazardous waste 8.40%, changes in biodiversity 5%, extraction of mineral resources 12.07%, financial risks 5.33%, loss of aquatic life 4.67%, and loss of fertility 3%, as derived from hierarchical and standardization matrices. Despite being grounded in a literature review and being constrained due to the scarcity of previous projects in the country, this research provides a useful framework for the environmental evaluation and planning of prefabricated housing. To conclude, this study enhances existing methodologies of environmental assessment techniques and practices in the construction of precast concrete and promotes the development of sustainable and socially responsible housing in Ecuador.

1. Introduction

Sustainability in construction is a concept that has gained increasing relevance in recent decades due to concerns about the environmental impact of human activities and the need to mitigate the effects of climate change [1]. In particular, the construction industry faces significant challenges, given that it is one of the sectors that contributes the most to environmental degradation, greenhouse gas emissions, and the consumption of natural resources [2,3,4]. For this reason, the integration of sustainable practices in construction, such as prefabricated housing, has emerged as a viable alternative to reduce the environmental impact of construction [5].

Prefabricated concrete homes have established themselves as a popular choice due to their durability, energy efficiency, and shorter construction time compared to traditional ones [2,6]. In the present context, the adoption of prefabrication in construction projects in developing economies remains low. For example, in Sri Lanka, a country with a low socioeconomic status, the implementation of modular technologies is progressing slowly compared to industrialized economies [7]. In Malaysia, data from the Construction Industry Development Board (CIDB) reports a population of 23,714 registered professionals and companies with an interest in prefabricated systems, reflecting a growth in attention to this technology, although its effective implementation still presents significant challenges [8]. Similarly, in Latin America, recent studies in Chile and Peru show that, although there are experiences in modular housing with materials with low environmental impact, their incorporation on a large scale is still incipient [9].

The potential of prefabricated housing to improve the circularity of the construction process is becoming increasingly evident. However, despite the well-documented benefits compared to traditional construction, the application of these technologies is lower globally [7]. In addition, like any type of building, they present challenges in terms of managing their life cycle, from the extraction of materials to demolition at the end of their useful life. The analysis of its sustainability involves considering multiple factors, including energy efficiency, use of materials, waste management, and the reduction in adverse impacts on the environment and human health [3].

In this context, international sustainability certifications, such as Leadership in Energy and Environmental Design (LEED), Building Research Establishment Environmental Assessment Methodology (BREEAM), and Building Benchmark Efficiency Assessment (VERDE), have established frameworks that allow sustainability in housing construction to be assessed [6,7,8,9,10]. These certifications are critical to promoting greener building practices, providing tools for measuring and improving the environmental performance of buildings [11].

However, although there are several studies on sustainability in construction, the application of these concepts to prefabricated concrete houses in specific regions, such as the Andean areas of Ecuador, remains an underexplored area [12,13,14]. Although prefabricated houses are widely disseminated and used worldwide due to their benefits in speed and construction efficiency [7,9], in Ecuador, their adoption, especially in rural and Andean areas, has been scarce and presents particular challenges in terms of the local socio-environmental and technological context [15]. The lack of previous projects in this area limits the availability of comparative and standardized data, which is one of the main barriers to the implementation of sustainable practices in this type of building. One of the methods used to assess and prioritize environmental impacts is the Hierarchical Analytical Process (AHP), a multi-criteria technique that allows prioritizing various alternatives based on paired comparisons [16]. This approach is useful for assessing the impacts of prefabricated concrete constructions, as it allows identifying which are the most key aspects to consider in terms of sustainability, such as the reduction in emissions, the responsible use of natural resources, and the conservation of biodiversity [17]. This highlights the pressing need for studies that provide evaluation tools adapted to the Ecuadorian context, especially to the Andean area, such as the one developed in this research.

This study seeks to evaluate the impacts and sustainability indicators in the construction of prefabricated concrete housing, using validated methodologies such as LEED, BREEAM, and VERDE [12]. The Hierarchical Analytical Process (AHP) will be applied to prioritize the most relevant environmental impacts in housing construction in the Andean areas of Ecuador. In addition, the relevance of environmental factors such as hydrology, soil, fauna, vegetation, and socioeconomic aspects will be analyzed to establish priorities for sustainable projects. The AHP will enable the prioritization of each impact, which will provide a clearer view of which environmental factors need to be addressed. The relevance of various environmental components within a regional system will be analyzed, such as hydrological factors, land use, fauna, vegetation, and socioeconomic aspects. This study allows us to establish a comparison with the environmental aspects defined in the article “Validation of Sustainability Criteria as a Tool for the Evaluation of Habitability of Pre-fabricated Concrete Homes for Andean Areas” [12]. In addition, it seeks to contribute to the development of future projects in Ecuador, adapted to the specific needs of the Andean areas and aimed at promoting sustainable construction practices. Finally, the proposal of validation and weighting tools that optimize the evaluation and classification of sustainability in the construction of prefabricated homes is proposed.

2. Materials and Methods

2.1. Bibliographic Review

LEED stands as the universal benchmark for evaluating the design, construction, and operation of high-performance green buildings [18]. It contains nine main categories of assessment: Location and Transportation, Sustainable Sites, Water Efficiency, Energy and Atmosphere, Materials and Resources, Indoor Environmental Quality, Integrative Process, Innovation, and Regional Priority. The certification is divided into four classifications that vary depending on the score: LEED certification (40 to 49 points), silver (50 to 59 points), gold (60 to 79 points), and platinum (80 to 110 points) [19]. BREEAM stands as the leading set of science-based validation and certification systems to promote sustainability in the built environment globally [20]. The main categories measured by BREEAM are energy, land use, materials, contamination, waste, water, health and well-being, transport, management, and innovation. BREEAM ratings range from ‘Acceptable’ (for buildings in use) to ‘Approved’, ‘Good’, ‘Very Good’, ‘Excellent’, and ‘Excellent’, schematically represented by stars on the certificate itself [19]. VERDE is a methodology for the environmental and energy assessment of buildings based on Life Cycle Assessment (LCA). Its objective is to measure and reduce the environmental impacts of a building by comparing it to a reference building, optimizing its energy efficiency and sustainability. The method assesses six main areas: plot and site, energy and atmosphere, natural resources, indoor environment, social and economic aspects, and building quality. The rating is expressed in “green leaves” (from 0 to 5), where 5 leaves indicate the highest level of sustainability [21].

For the environmental diagnosis and the specification of the hierarchy and importance of environmental impacts, a methodology is provided in which the percentage terms are analyzed, analyzing the relevance of the environmental components within a regional system, and the weighting of hydrological, soil, fauna, vegetation, and socioeconomic factors is analyzed [10]. To this end, three sustainability certification methodologies were analyzed: LEED, BREEAM, and VERDE, selecting their impacts, indicators, and weights that establish a scoring system that is based on the relative importance of each environmental category. This weighting is determined according to a methodology developed by the U.S. Green Building Council (USGBC), and is based on seven priority areas of environmental and human health impact. In addition, evaluation methods use what it calls an “Impact Categories Framework.” This framework defines the most important environmental goals that the system wants to achieve and how much each credit helps to achieve those goals [22].

Table 1. Impacts and indicators in LEED 2009 certification (adapted from [23]).

IMPACT	INDICATOR	WEIGHT
Climate change	KgCO2 eq/uf	27%
Destruction of the ozone layer	Kg CFC11 eq/uf	2%
Acidification	Kg SO2 eq/uf	26%
Eutrophication	Kg PO4 eq/uf	6%
Stratospheric ozone depletion	Kg of C2H4 eq.	31%
Non-renewable primary energy	MJ	8%

,

Table 2. Impacts and indicators assessed for GREEN certification (adapted from [24]).

IMPACT	INDICATOR	WEIGHT
Climate change	KgCO2 eq.	25%
Increased UV radiation at ground level	Kg of CFC11 eq	0%
Loss of fertility	Kg of SO2 eq	5%
Loss of aquatic life	Kg PO4 eq.	5%
Cancer production and health problems	Kg of C2H4 eq.	8%
Changes in biodiversity	%	5%
Non-renewable energy depletion and primary energy	MJ	8%
Depletion of non-renewable resources other than primary energy	KgSb eq.	8%
Drinking water depletion	m3	10%
Generation of non-hazardous waste	medical history	6%
Loss of health and comfort and quality for users	%	15%
Financial risk or benefits to investor life cycle cost	$/m2	5

and

Table 3. Impacts and indicators assessed for BREEAM certification (adapted from [23]).

IMPACT	INDICATOR	WEIGHT
Climate change	KgCO2 eq.	21.6%
Water extraction	m3	9%
Mineral Resource Extraction	Tons	7%
Stratospheric ozone depletion	kg CFC-11 eq	7%
Ecotoxicity for freshwater and land	Kg 1.4-DB eq	6%
Nuclear waste	mm3 High Level Waste	7%
Garbage Dump	ton of solid waste	6%
Fossil fuel depletion	tons of oil eq. (toe)	17.5%
Eutrophication	kg phosphate (PO4) eq.	6%
Creating Photochemical Ozone	kg eteno (C2H4) eq.	6%
Acidification	kg azufre dioxide (SO2) eq.	7%

show the proposals for minimum impacts necessary for the evaluations and the corresponding indicators for calculating the impacts. It should be noted that, although individual impacts are quantified through objective indicators obtained from LCA, the assignment of relative weights incorporates a subjective component. This is because certification schemes set impact priorities based on expert decisions, thus reflecting value judgments about the relative importance of each environmental category.

Each certification methodology provides established reference values; in the case of the BREEAM methodology, it does not define predetermined weights, as these vary depending on the seasonality. However, since the Ecuadorian Andean region does not present significant seasonal variations, it is considered that the applicable weights are similar to those used in other areas.

2.2. Hierarchical Analysis Process (AHP)

According to Bermúdez and Quiñonez (2018) [23] and Al-Harbi (2001) [25], the hierarchical analysis (AHP) process is a methodological tool that allows the evaluation of different criteria by granting a hierarchy to each of them to optimize decision-making. Comparisons are made through a numerical scale from 1 to 9 that entails a comparison of two aspects through scores. The AHP method breaks down a problem and then unites all the solutions of the subproblems into a single conclusion [26]. Figure 1 shows the analysis of the methods for rating impacts and indicators.

2.3. Pairwise Comparisons

To make the suggested paired comparisons, a numerical scale is required that indicates the importance of one element over another, with respect to the impact with which they are being compared. That is, the scale with values between 1 and 9 is used to rate the relative preferences of two items, as indicated in

Table 4. Saaty comparison scale [28].

VALUE	DEFINITION	FEEDBACK
9	Absolutely more important than	When comparing one element with the other, the former is considered absolutely or vastly more important than the latter.
7	Much more important or preferred than	When comparing one element to the other, the former is considered much more important or preferred than the latter.
5	More important or preferred than	When comparing one element to the other, the former is considered more important or preferred than the latter.
3	Slightly more important or preferred than	When comparing one element to the other, the former is slightly more important or preferred than the latter.
1	Equal or indifferent to	When comparing one element with the other, there is indifference between them.
1/3	Slightly less important than	When comparing one element to the other, the former is considered slightly less important or preferred than the latter.
1/5	Less important or preferred than	When comparing one element to the other, the former is considered less important or preferred than the latter.
1/7	Much less important or preferred than	When comparing one element to the other, the former is considered much less important or preferred than the latter.
1/9	Absolutely less important than	When comparing one element to the other, the former is considered absolutely or far less important or preferred than the latter.

. Similarly, there are intermediate values of 2, 4, 6, and 8 as well as reciprocal values of (1/2), (1/4), (1/6), and (1/8) [25].

2.4. Method for Applying AHP

To carry out the evaluation of impacts and indicators based on different certification methodologies, the available methods are first identified. Subsequently, the common and most relevant impacts to be considered in the Ecuadorian case are selected, ensuring that the evaluation reflects the most critical aspects. Once the key impacts have been defined, a general matrix is constructed that allows us to see the values obtained in each methodology. The values of each column are then added within the matrix, allowing the structuring of paired comparisons between impacts and indicators [29]. Each component of the matrix is divided by the total sum of its respective column, thus obtaining a normalized matrix that facilitates the hierarchy of impacts according to their relative importance. Subsequently, the average of each row is calculated, representing the relative priority of the evaluated elements.

To ensure the consistency of the calculations, the row vector is determined, which is obtained by multiplying the initial comparison matrix by the average vector. Then, the Landa vector is calculated, which allows the consistency of the model to be verified by the relationship between the values of the row vector and the average vector. To assess the consistency of the matrix, the consistency index (CI) and the randomness index (AI) are calculated, which determine whether the weighting assigned to the criteria is reliable. Finally, the process culminates with the calculation of the eigenvector through successive iterations on the weighting matrix. This eigenvector represents the final importance of each impact within the analysis to obtain alternative results and criteria, thus allowing the determination of the final magnitude of the impacts based on their relevance within the evaluation model [29]. Once the calculations of all the combined comparisons and together with the impacts compared by the experts have been concluded, the final consensus result is reached: it allows the hierarchical analysis of the impacts and indicators evaluated, finding the best alternative that reflects the method that best adapts to the reality under study [28].

To guide the AHP application and evaluation of LEED, BREEAM, and VERDE certifications in the Ecuadorian context, the following research questions are explicitly formulated: How do international sustainability certifications (LEED, BREEAM, VERDE) align with the environmental impacts of prefabricated concrete housing in the Andean region of Ecuador? What environmental impacts are most relevant for prefabricated concrete houses in Ecuador according to the prioritization of the AHP? And to what extent can the application of these certifications be adapted to improve the evaluation of sustainability in the Ecuadorian context?

3. Results and Discussion

Climate change is assessed as one of the most important impacts found in LEED, GREEN, and BREEAM certifications. In GREEN certification, it represents a value of 25%; in BREEAM certification, it represents a value of 21.6%; and in LEED certification, it represents a value of 27% [23,24]. This impact is measured through the amount of carbon dioxide equivalent emissions (kgCO₂eq) generated per functional unit, using LCA. In terms of water use, LEED’s “Water Use Efficiency” category seeks to promote its rational use and reduce its consumption in construction [23], assigning it a weight of 15%. In BREEAM, this weight is 9%, and in GREEN, it reaches 23%. However, in the GREEN certification, this 23% is not concentrated in a single category, but is distributed: 8% corresponds to the production of cancer and health problems, and 15% to losses of health, comfort, and quality of life [24]. This distribution reflects the different effects that water consumption generates on human health and the environment.

Table 5. Environmental impacts of LEED, GREEN, and BREEAM certifications applying the (AHP) methodology.

IMPACT COMPARISON	Climate Change	Loss of Human Health	Drinking Water Depletion	Mineral Resource Extraction	Garbage Dump	Financial Risks	Non-Hazardous Waste	Loss of Aquatic Life	Changes in Biodiversity	Loss of Fertility
Climate change	1	1/3	1/5	1/3	1/3	1/5	1/4	1/5	1/5	1/5
Loss of human health	3	1	1/3	2	2	3	3	2	2	3
Drinking water depletion	5	3	1	4	3	4	5	3	3	3
Mineral Resource Extraction	3	1/2	1/4	1	2	1/3	2	1/2	1/2	1/2
Garbage Dump	3	1/2	1/3	1/2	1	1/3	1/3	1/2	1/3	1/3
Financial risks	5	1/3	1/4	3	3	1	2	1/2	1/2	1/2
Generation of non-hazardous waste	4	1/3	1/5	1/2	3	1/2	1	1/2	1/3	1/2
Loss of aquatic life	5	1/2	1/3	2	2	2	2	1	1/3	1/2
Changes in biodiversity	5	1/2	1/3	2	3	2	3	3	1	3
Loss of fertility	5	1/3	1/3	2	3	2	2	2	1/3	1
Sum	39	7.33	3.57	17.33	22.33	15.37	20.58	13.20	8.53	12.53

shows the assessment and prioritization of environmental impacts in the construction of prefabricated housing, using the AHP method. In this process, the environmental impacts of LEED, BREEAM, and VERDE certifications were compared using a matrix of paired comparisons based on the Saaty scale. Each impact was evaluated according to its relative importance with respect to the others, using values from 1 to 9 established on the Saaty scale [25] and its reciprocal ones. This comparison made it possible to establish the priority of each impact within the sustainability analysis in buildings [24]. The impacts are linked to different credits, forming specific groupings. The score given to each credit is proportional to both the number of associated impacts and the relative weight of each. In addition, the final weighting is determined by considering an efficient reference home as a basis for comparison.

Based on the above, Table 5 shows that the criterion with the greatest weight is climate change, influenced by the CO₂ emissions associated with the manufacture [4] and transport of prefabricated materials [9,30]. However, Ecuador has greenhouse gas reduction policies in all its strategic sectors [24]. Next, the depletion of drinking water is one of the least critical criteria, due to the use of water resources both in the production of materials and in the construction phase [24], in addition to the waterproofing of the soil, which limits the recharge of aquifers; however, it generates a lower impact than traditional buildings [9]. However, the situation changes when considering the Andean region as a whole, where water availability varies seasonally and is subject to pressures from agricultural demand, urban growth, and changes in land use [31]. Recent studies highlight that water pressure in micro-watersheds in the Ecuadorian Andes affects not only the quality of the resource, but also the capacity of ecosystems to sustain essential environmental services such as biodiversity and soil fertility [32]. This suggests that, although globally this impact is perceived as moderate, in the Andean regional context, it could acquire greater relevance and should be considered in future adaptations of the AHP model.

Similarly, the loss of biodiversity with 12% and the loss of soil fertility 8% present significant values due to the direct impact of urbanization on the surrounding ecosystems and the decrease in water availability and quality [33]. The results indicate that water use efficiency and ecosystem protection are key aspects in the sustainability of buildings. In contrast, criteria such as the generation of non-hazardous waste (20.58), and financial risks (15.37) have a moderate impact, since the current cost of prefabricated housing optimizes the use of materials and reduces operating costs [12,34]; for example, in Chile it has been shown that a prefabricated system is almost 30% less than that of a conventional house [9], suggesting that its influence on sustainability is less critical compared to other environmental factors. The numerical score of these factors reflects a relative importance in the set of criteria, but the qualitative assessment indicates that, although numerically high, they do not represent critical threats to sustainability compared to other impacts of greater magnitude or difficulty to mitigate.

The results obtained in Table 5 show that the most relevant environmental impact is climate change, with a weighting of 28.77%, which positions it as the priority criterion in the sustainability assessment of prefabricated housing. This importance is mainly attributed to the emissions associated with transport, energy consumption, and construction processes. Other notable impacts include the depletion of drinking water (15%) and the impact on biodiversity (12%), which shows the need to design homes that are not only climate-resilient but also efficient in the use of water resources and with a smaller ecological footprint.

Table 6. Unified impacts for the 3 BREEAM, LEED, and GREEN certification methodologies.

Impacts	Indicators	Weight
Climate change	KgCO2 eq/uf	27%
Drinking water depletion	m3	15%
Changes in biodiversity	%	12%
Financial risks	$/m2	10%
Loss of fertility	Kg SO2 eq	8%
Loss of aquatic life	Kg PO4 eq	8%
Generation of non-hazardous waste	Medical history	6%
Loss of health and comfort and quality for users	%	5%
Mineral Resource Extraction	Tn	5%
Garbage Dump	Tn	5%

presents the most important impacts based on the current situation of Ecuador and its Andean areas, developing an analysis of the importance of impacts according to the certification method. The results provide a solid basis for decision-making in sustainable construction projects in Ecuador. The weights of the impacts were obtained by applying the AHP, using the Saaty matrix to make paired comparisons between the criteria of the BREEAM, LEED, and VERDE certification methodologies. For each impact, preference values were assigned according to the scale of 1 to 9 proposed by Saaty (2013) [35], based on their relative importance in the Ecuadorian context. Subsequently, the consistency index (CR) was verified to ensure the coherence of the judgments, and the eigenvectors that determine the final weight of each impact were calculated. In the evaluation of the sustainability of buildings, each environmental impact contributes to the total impact on the environment. To guarantee an objective comparison, the sum of the weights assigned to the impacts must be equal to 100%, representing the total environmental impact of the evaluated system. If more environmental impacts are incorporated into the assessment, the distribution of weights will be adjusted proportionately to maintain consistency in the analysis. On the contrary, if fewer impacts are evaluated, the total will be less than 100%, reflecting that some factors have not been evaluated.

The weights act as penalties within the analysis of the energy and environmental performance of the home. An impact with a higher weighting implies a greater penalty, indicating that its contribution to environmental degradation is more significant, for example, in the case of climate change evidenced that during the life cycle stage, lower carbon emissions (7.17%) were found in prefabricated buildings compared to traditional buildings and indicate that the optimization of the thermal insulation of prefabricated buildings is an efficient way to achieve energy savings and a reduction in carbon emissions during their life cycle. On the other hand, the main reason for the lower weights, as is the case with the extraction of mineral resources, is that the houses use prefabricated components, which can effectively reduce the consumption of concrete, steel and wood, that is, a 9.32% lower consumption of resources compared to traditional buildings. The fabricated members use steel templates in the production process, avoiding the use of wooden templates. Similarly, in the case of the impact generation of non-hazardous waste and garbage disposal, most of the waste is generated in the process of material replacement and demolition, and is 15.90% lower than in traditional buildings. In a Chilean study, it has been evidenced that building components, such as doors, windows, and partitions, cannot be reused due to their inevitable destruction; however, prefabricated buildings also showed higher recycling rates than traditional buildings [35,36]. On the other hand, in prototypes of prefabricated houses developed in similar contexts, for example, Mexico and Ecuador (Guamote), it has been identified that, in regions with high thermal oscillations, such as the Andean area of Ecuador, it is essential to strengthen construction solutions in terms of thermal inertia and insulation. Homes in these areas require designs that allow adequate thermal comfort to be maintained in the face of extreme temperature variations between day and night, reducing dependence on active air conditioning systems. The incorporation of passive strategies, such as the optimization of insulation and the use of materials with high thermal storage capacity, is presented as a viable alternative to improve energy efficiency in low-cost housing, both in urban and rural environments of the Ecuadorian highlands, where climatic conditions impose significant challenges to the design of sustainable buildings [15].

Table 7. Impacts analyzed with their respective total scores on housing constructions for the high Andean areas of Ecuador.

	Impact	Indicators	Weight	AHP	Total Score
1	Climate change	kgCO2 eq/uf	28.77%	2.75	28.91
2	Drinking water depletion	m3	13.73%	1.83	19.29
3	Loss of human health	%	19.17%	1.35	14.25
4	Generation of non-hazardous waste	Tn	8.40%	1.32	13.87
5	Changes in biodiversity	%	5%	0.71	7.45
6	Mineral Resource Extraction	Tn	12.07%	0.52	5.53
7	Financial risks	$/m2	5.33%	0.43	4.56
8	Loss of aquatic life	kg PO4 eq.	4.67%	0.37	3.89
9	Loss of fertility	kg of SO2 eq	3%	0.21	2.25

describes the importance in weight of each of the impacts analyzed in the construction of prefabricated houses for Ecuador, where climate change obtains a weight of 28.77% in response to the use of transportation and demand for the use of materials with a high carbon footprint [9,30] and a water depletion of 13.73%, mainly due to the manufacture of concrete. Especially in the Andean zone, this impact is evident, directly affecting the scarcity of water due to climate variability [31,32], the loss of human health is 19.17%, because most accidents occur during the lifting and installation of components on construction sites [35], as well as the installation of inadequate thermal insulation that affects the quality of life. The generation of non-hazardous waste is 8.40% [35], changes in biodiversity are 5%, extraction of mineral resources is 12.07%, financial risks are 5.33%, loss of aquatic life is 4.67% in response to eutrophication processes and pollution of water resources due to the reuse of materials such as steel, aluminum, and iron in the production of prefabricated concrete houses [7,36], and loss of soil fertility is 3% due to soil compaction or the use of non-biodegradable materials that affect the resilience of natural ecosystems, especially in the Andean zone [31,32]. To obtain these results, the impact hierarchy matrix and the normalized matrix for the calculation of the weights were made. In one way or another, all these impacts have affected the habitability of homes due to changes in global temperature, loss of soil fertility, changes in biodiversity both at the aquatic and terrestrial levels, damage to people’s health, and depletion of drinking water, among others [34].

To understand the relationship between the data presented in Table 5, Table 6 and Table 7, a flow chart was developed (Figure 2) that summarizes the analysis process followed. Table 5 initially identifies the environmental impacts and indicators derived from the specialized literature. Based on this basis, Table 6 shows the hierarchy of these impacts through the application of the AHP method, reflecting the relative priority assigned to each one. Finally, Table 7 presents the adjusted weighting of these impacts, considering the reality of Ecuador through the assessment carried out by experts. This scheme made it possible to show how the final weighting integrates both the bibliographic review and the expert judgment, showing a coherent and orderly process of analysis and validation of environmental impacts.

4. Conclusions

Through the literature review, the impacts and key indicators for sustainability in the construction sector were identified, using the LEED, BREEAM, and VERDE certifications, applied to prefabricated concrete houses in Ecuador. From the prioritization of impacts through the AHP method, it was determined that climate change, drinking water depletion, and loss of human health are the most relevant impacts. The results suggest that LEED presents greater adaptability to the Ecuadorian context due to its flexible focus on reducing CO₂ emissions, optimization of water consumption, and energy efficiency. Although BREEAM and VERDE are robust systems, their requirements are more closely linked to European regulations, which makes it difficult to adapt directly to the Ecuadorian reality, especially in high Andean areas. Therefore, it is recommended to promote public policies that develop a national technical regulation based on the structure of LEED, incorporating local criteria such as the use of low-impact materials, efficient waste management, and biodiversity conservation. The applied methodology provides a quantifiable framework for decision-making in environmental certification projects, facilitating the planning and execution of sustainable constructions in Ecuador.