Are Sustainable Building Certifications Delivering Better Performing Buildings?
1 - INTRODUCTION
The last three decades saw an increasing awareness of sustainability. “Green” is used interchangeably with “sustainability” (Berardi, 2013; Wong and Zhou, 2015) and industries are more and more “going green”, trying to reduce pollution and increasing their profits (Hart, 1996).
With the significant population growth and the rapid urbanization, 68% of the population expected to live in cities by 2050, the need for new buildings continues to increase to meet the demand of the expected additional 13% of citizens (United Nations, 2018). Even with providing shelters and satisfying that growing need, the construction industry has been massively denounced for all the adverse impacts it can have on the environment and even human health. The construction industry is negatively characterized by what is called the “40% impact”, consuming 40% of global resources (Yeheyis et al., 2013), 40% of the energy (during extraction, processing and transportation of raw materials) (Doan et al., 2017), emitting 40% of the greenhouse gases (Dimoudi and Tompa, 2008; Miller et al., 2015) and producing 40% of total solid waste (Udawatta et al., 2015).
The alarming statistics are leading towards the emergence of sustainability in construction to mitigate these repercussions. Sustainable construction is gaining a tremendous development globally, it drives governments to set up or upgrade local policies on energy efficiency and emissions reduction. In that sense, it soars up existing regulations in developed countries and triggers the establishment of new ones in developing countries. As an example, according to Shi, Zuo, Huang and Pullen, the ministry of construction in China introduced in 1986 the first energy efficiency standard in one of the regions, spreading it later to other areas before coming up in 2005 with national regulation (Shi et al., 2013). In addition, a renewable energy law was announced in 2006 that would enhance conventional energy savings (Shi et al., 2013). Similarly, Morocco saw the emergence of its thermal regulation in 2015 followed the same year by a law for promoting energy efficiency (Ministère de l’Energie des Mines de l’Eau et de l’Environnement, 2015). Following these trends, sustainable buildings had become one of the most thorough areas of interest in publications within the built environment, as represented in the increase in numbers of publications by 300% (Ghaffarianhoseini et al., 2013).
This pervasive growth of interest in sustainable construction needed a yardstick for measuring the reduced environmental impacts. Since the introduction of the first environmental performance evaluation methods worldwide in 1990 (BRE, 2019b), it was supported with the development of assessment schemes and certifications that guarantee third-party verification of the announced enhanced performance of the buildings.
In their critical review of the existing body of knowledge on green buildings, Zuo and Zhao highlighted that most researchers are developed around defining sustainable buildings, understanding the motivations behind certifying them and suggesting how to implement them (Zuo and Zhao, 2014). Following the gaps identified, the aim of this paper is to assess the real performance of such buildings by exploring if the third-party certified buildings are performing as intended.
2 - METHODOLOGY
This research was developed to elucidate the essence of the impact of sustainable building assessment tools on the resulted building performance. In order to do so, a methodical recovery and analysis of existing publications were crucial. This literature review was developed in 3 steps.
(1) To retrieve relevant published researches, varied general databases were used such as Google Scholar, iDiscover, Elsevier. A keywords search was then adopted to identify relevant journals, articles and conference proceedings. The search codes were different combinations of “sustainable”, “green”, “buildings”, “construction”, “certification”, “assessment”, “scheme”, “performance”, “advantages”, “critics”, “challenges”, “cost”, “satisfaction”.
(2) A first scanning of the abstract and motivations of authors allowed to filter irrelevant articles for the purpose of this study. Out of 130 results, only 64 were selected.
(3) Results were classified into themes and a mind map allowed cross-evaluating their findings and limitations in order to present the analysis and limitation of this research. The analysis starts wide with a general overview of sustainable buildings and their assessment schemes before narrowing down to advantages and challenges that constitute pieces of the answer to the general question.
3 - ANALYSIS
3.1 What is a sustainable building?
Since the emergence of this concept, difficulties were constantly raised about precisely defining the terminologies of “green” and “sustainable” buildings (Fowke and Prasad, 1996; Cole, 1998, 2004; Berardi, 2013). According to the World Green Building Council (WGBC), a building is green if “in its design, construction or operation, reduces or eliminates negative impacts, and can create positive impacts, on our climate and natural environment” (World Green Building Council, 2016). This definition overlaps with the previously recognized one of Cole citing mitigation of environmental and ecological damage compared to typical practice (Cole, 2006). All attempts to define “green” agree on resources efficiency, pollution reduction and environmental protection (Haapio and Viitaniemi, 2008; Kibert, 2016; Li et al., 2016).
From the other side, sustainability is usually linked to the triple bottom line, adding up social and economic dimensions to the environmental one (Berkes and Folke, 1998; Pope, Annandale and Morrison-Saunders, 2004; Epstein, 2008). Furthermore, the definition of sustainable buildings, being on the mend, is constantly revised, as pictured in Figure 1, with researches adding a vast array of dimensions: institutional (Spangenberg, 2002; Sharifi and Murayama, 2013), cultural (Mateus and Bragança, 2011) or political (Hopwood, Mellor and Brien, 2005; Hugé et al., 2013). In 2003, the United Nations Environment Program studied the major differences between green and sustainable buildings, highlighting aspects that are covered in sustainable construction beyond everything else covered in green construction and those are among others: longevity, facilities management, operations and maintenance, social, economic and cultural spheres. Berardi (2013) explored different perspectives of this interdisciplinary notion to end up defining it as a building that “contributes to the sustainability through its metabolism and by doing this it favours a regenerative resilience of the built environment among all the domains of sustainability”.
Figure 1. Dimensions of sustainability (adapted from (Doan et al., 2017))
When exploring the body of knowledge on green buildings, whether in developed or in developing countries, three main patterns of research were identified (Zuo and Zhao, 2014):
while the first group of researchers focus on the “WHAT” sphere, trying to define the complex notion of green or sustainable buildings and their scope,
a second category concentrates on the “WHY” sphere, trying to explain the drivers of implementation of sustainable buildings and centralizing the analysis on the costs and benefits these buildings can have.
The third cluster of researchers concentrates on the “HOW”, that can be seen either from a process or a result perspective, depending on if they are trying to bring directions and solutions to implement and achieve sustainable building or trying to suggest new frameworks to evaluate the performance of these buildings.
This literature review will inspect some of the “How” researches to introduce the role of assessment schemes in fulfilling sustainability in buildings before studying the “why” to analyse the outcomes of applying those certifications on the real performance of buildings.
3.2 Green Building Assessment Systems
In a time where sustainable buildings are suffering from a definitional ambiguity, certifications and assessment schemes have been developed providing a yardstick for assessing the sustainability of buildings. Most of them such as BREEAM, LEED, Casbee, Green Star, HQE… are launched by non-governmental organizations in different countries usually named “green building councils”. The different councils operate under the umbrella of the WGBC that had been established to link the different initiatives and build a common understanding and vision.
However, several researchers raised the lack of coverage of the different dimensions of sustainability. Energy, having the biggest weight on the different schemes is still the most important criteria in almost all certifications (Cole, 2004; Berardi, 2012). As a result, buildings are reduced to a resources consumer (Lowe, 2007; Conte and Monno, 2012) and sustainable buildings are frequently confounded with green, high performance and energy-efficient buildings due to the interchangeable use of the different terms (EPA, 2008).
These certifications are voluntary-based and widely used by developers and contractors to confirm their engagement towards sustainability either in developed or developing countries. However, they are developed to upgrade national standards from minimal to an aspirational level through a market pull (BRE, 2019b). Following this trend, some authorities such as the UK government requires new construction and retrofits to be BREEAM-certified (Chegut, Eichholtz and Kok, 2014). In addition, new regulations and codes integrate stringent energy efficiency measures such as the introduction of zero-carbon standards in the UK (Chegut, Eichholtz and Kok, 2014), France (Sauer and Mathesen, 2019) and Australia (Maddew, 2015). The existing assessment schemes follow an index judgement method and are guidelines and checklists that allow having a number of points by implementing suggested strategies. Furthermore, the requirements listed are either mandatory “prerequisites” or “credits” that can be collected to reach a better level. The total number of points is then converted to a score either through a simple addition or a conversion to a weighting in percentages or a number of stars in HQE and Green Star for example. Some of the most adopted certifications and their characteristics are restated in table 1 below.
It is also worth emphasizing that, weights allocated to each of the credits gives more significance than the number of credits in the different themes in the contribution towards the components of the triple-bottom-line (Mattoni et al., 2018). For example, in LEED2 certification, “Indoor Environmental Quality” theme has the highest number of credits (9) for a maximum score of 16 points while the theme “Energy and Atmosphere” has a lower number of credits (7) giving 33 points with 18 points assigned to a single credit “Optimize Energy Performance”. In that sense, the credit about energy performance is the most considerable one in LEED, monopolizing 18% of the certification. It is worth reminding that the different certifications knew several revisions and their recent versions reveal their answer to the previously cited critiques about the integration and balance between dimensions of sustainability. From the analysis of the current themes schematized in Figure 2, it can be emphasized that the environmental sphere is still dominating in terms of weighting and more efforts should be directed towards the economic analysis of sustainable buildings.
He et al. tried to pinpoint the differences between assessment methods and pointed out the lack of research on the impacts those certifications can have on the design choices and the resulting performance of the buildings (He et al., 2018). Through a case study approach, comparing the effects of LEED, Assessment Standard for Green Buildings (ASGB) and Green Star, they have found out that performance-based rating systems such as Green Star have a better impact on the sustainable design than design-guide assessments such as ASGB or LEED (He et al., 2018).
Table 1. Major sustainable buildings assessment tools (adapted from the Guide to Sustainable Building Certifications,(Jensen and Birgisdottir, 2018))
Figure 2. Sustainability categories coverage in different assessment schemes (adapted from the Guide to Sustainable Building Certifications, (Jensen and Birgisdottir, 2018))
3.3 Certifications as a driver for sustainabl-ing buildings
Since its introduction in 2000, a decade after BREEAM, LEED certification conquered the market of sustainable buildings penetrating 162 countries in 2016 (USGBC, 2016) and outpacing the BREEAM present in 81 countries in 2019 (BRE, 2019a). However, there is a lack of evidence to support the real added value on the performance of those buildings. Therefore, after having gathered 6 years of data from delivered buildings, the USGBC contracted the New Buildings Institute (NBI) to analyse the savings in energy from certified commercial buildings. NBI reported a better energy performance (25-30%) for LEED buildings over the national average (Turner and Frankel, 2008). Three years later, Newsham, Mancini and Birth focused their research on energy use as a result of implementing the LEED rating system (Newsham, Mancini and Birt, 2009). Starting from Turner and Frankel’s report comparing the median EUI for LEED buildings to the mean in CBECS (Commercial Building Energy Consumption Survey) database (EIA, 2003), they brought more accuracy to the initial conclusions by reviewing the pairing between the 100 LEED buildings and the closest match of the 5215 buildings of the CBECS dataset. After re-analysing the 100 commercial and institutional buildings, they have found out that certified buildings were 18-39% more energy-efficient than non-certified buildings which is a more widespread result than the initial findings with a clearer and more rigorous statistical analysis.
More globally, sustainable building standards are not only impacting the economic sphere through a reduction in energy bills, but they contribute to a higher valuation of properties (Popescu et al., 2012). Fuerst and Mcallister discovered that LEED and Energy Star certified buildings benefit from sales prices 25-26% higher than non-certified ones (Fuerst and Mcallister, 2011b), and Chegut, Eichholtz and Kok completed the research on the BREEAM part resulting in 14,7% higher sales transactions and 19,7% rents premium relative to non-certified buildings within the same neighbourhoods (Chegut, Eichholtz and Kok, 2014). Miller, Spivey and Florance explained this higher value by the lack of supply, allowing those buildings to have higher occupancy rates and quickly offset the negligible (1-7%) costs to go green (Miller, Spivey and Florance, 2008). Furthermore, albeit financial performance of certified buildings is found to be enhanced, non-certified buildings within the same area capture some gentrification benefits and see their rents increased improving the whole neighbourhood value (Chegut, Eichholtz and Kok, 2014). Also, positive economic externalities reach non-certified buildings creating a market of competition to achieve certifications as the number of sustainable buildings diffuse (Chegut, Eichholtz and Kok, 2014).
To sum up, green building certifications truly contribute to environmental and economic aspects of sustainability through the delivery of more energy-efficient buildings. They were found also to impact positively the property values through higher selling prices achieved not only for the buildings themselves but for the real estate market surrounding them.
3.4 Challenges and critics
The previously cited NBI’s report emphasizing on better performing LEED-certified buildings encountered several critics (Lstiburek, 2008; Richter et al., 2008; Scofield, 2009). H. Grifford and J.W. Lstiburek agreed on two failures of the research being the unreliable sample due to a voluntary gathering of data (Gifford, no date; Lstiburek, 2008). Together with Newsham, Mancini and Birth, they revealed a distortion in the methodology for the comparison of the two data sets: the median of energy use intensity (EUI) for LEED buildings was contrasted to the mean of EUI for the conventional constructions of the CBECS data set. Furthermore, when calculating the mean EUI for the 121 buildings of the LEED sample, they have discovered that it is higher than the one of the national average of the opposing sample (Lstiburek, 2008; Richter et al., 2008; Scofield, 2009).
Surprisingly, Newsham, Mancini and Birth also discovered that third (28-35%) of the stock of certified buildings were using more energy than their conventional correspondents from the CBECS dataset. Furthermore, these researchers also underlined the lack of publications on post-occupancy evaluations (POEs) of occupied buildings (Newsham, Mancini and Birt, 2009), which is the path of evaluating the performance gap between design expectations and operations reality. Investigating the issue from another angle, Diamond et al. supported this lack suggesting extensive research on modelled vs. actual energy use (Diamond et al., 2006). Additionally, Shi et al. in their analysis of incompatible objectives behind green building projects suggested solutions at several development stages to solve conflicts between certification achievement, cost-effectiveness, functional effectiveness and demonstration effect. They pointed out the practice of sacrificing building functions due to cost constraints in order to reduce energy consumptions and proposed POEs as a mean to clarify the conflict between function and cost while integrating social and economic aspects to the analysis (Shi et al., 2016).
In addition, Scofield further analysed the previously cited data set integrating a different approach: he weighted the mean using the size (gsf) for each of the buildings. In that way, instead of using a “building-weighted” average, his calculation was more representative of the sample since large buildings are dominating energy consumption and should have a greater impact than smaller commercial constructions. Surprisingly, he uncovered half (10-17%) reduction of site energy than Newsham, Mancini and Birth’s findings. Scofield’s result is not astonishing when searching further in motivations and selected LEED credits in each of these buildings. It is more obvious when thinking that smaller projects are usually experimental and investments can allow budgets for energy-efficient or renewables strategies such as on-site energy generation through photovoltaic arrays while bigger projects need a more considerable initial investment to reach the same results, leading their designers to impel towards easier points such as bicycle racks (Scofield, 2009). Similarly, the cost is not the only barrier, a study of certification trends in the MENA region pointed out the chasing of points having less initial investment due to the lack of availability of materials and solutions and experienced professionals (Ismaeel, 2019). Furthermore, Chan et al. in their research of barriers impeding the adoption of green building technologies in Ghana added to the cost, the lack of government incentives and financing schemes for advocacy and achievement of better sustainable buildings as the top three obstacles. They have also noted that barriers vary between developed and developing countries (Chan et al., 2018).
As a result, reports can unveil different performance numbers on certified buildings, but a more careful analysis of the methodologies and samples adopted need to be carried. Indeed, certification is only one of the facets of the different parameters and investment strategies to create a performing and market-leading asset (Fuerst and Mcallister, 2011a). Furthermore, when a building is certified, a meticulous consideration needs to be addressed to the motivation of the owners to assess whether they have pursued certification as a guideline to build better buildings or as a mean to increase financial values while delivering less investment in more beneficial solutions. This investigation can be driven by analysing buildings scorecards and verifying the allocation of points and the coverage of credits contributing most towards building performance.
4 - CONCLUSIONS
Voluntary certifications for buildings emerged as a framework, providing guidelines for buildings to reach sustainability. While these assessment schemes’ popularity is increasing along with their competition and duplications, their adoption is still plagued with barriers and criticism is broadening the limits and deficiencies in their effectiveness. Despite the vast array of literature on sustainable buildings and assessment schemes, there is a lack of a thorough piece of research on the analysis of the performance these certifications are delivering. The question in this literature review was about exploring whether certifications are leading sustainability in buildings towards better-performing buildings or a disguise to trade and redeem the cash value behind the “green” movement.
What is conspicuous through the topic explored is a need for a more comprehensive analysis of direct impacts of certifications on the performance of the buildings and especially side-by-side comparisons of similar buildings in similar contexts with and without certifications, and not just in terms of energy performance but in different parameters such as comfort, aesthetics, economic returns, social recognition… Therefore, one of the challenges is setting this hedonic model that can encompass all of the parameters. The question “what would happen in the absence of certifications” remains worth exploring from different perspectives and within different contexts because if a building is high performing, certification may be one of the elements contributing to this result and is not necessarily the most impactful.
The positive finding is the proliferation of certifications that are developed to encourage market shifts and trigger government pressure to come up with more drastic regulations. However, the number of certified buildings is still not aligned with the exponentially increasing trend of constructing buildings. Therefore, future research should also consider exploring the reasons impeding the development of certifications if all these tools are more and more enhanced to bring value.
