Opportunities in the Sustainable Built Environment: Perspectives on Human-Centric Approaches

Abstract

Climate change and natural disasters have brought threats to humanity greater than ever. The built environment is a critical part of the climate action plan in terms of its resilience and sustainability. The growing awareness of sustainability in the built environment has led to the increased uptake of sustainable buildings and infrastructure projects. However, a growing number of studies reported some forms of performance gaps in achieving sustainability, in which the actual outcomes and performance of buildings were far from the expected goals. Researchers started to question the alleged benefits of the sustainable built environment. Apart from being overoptimistic in setting the environmental goals, some studies suggested that the gaps could arise from a negligence of the interplay between humans and the environment for delivering the sustainability goals. Hence, this paper intends to highlight opportunities in optimizing sustainability performance in the built environment via human-centric approaches. By placing human needs at the focal point, human-centric solutions would empower stakeholders to harness sustainable goals in the built environment effectively. A conceptual framework has been proposed to consolidate the findings and highlight human-centric solutions in between research gaps and opportunities in sustainable built environment research.

1. Introduction

Climate change and natural disasters are of critical concerns in the recent decades. The world has been suffering from record-breaking floods, wildfires, hurricanes, droughts, winter storms, typhoons, and heatwaves, which will continue to exert widespread impacts to people’s lives in the years ahead. The built environment plays an important role in dealing with the effects of climate change and natural disasters, particularly for driving meaningful sustainability initiatives into the climate action plan.

Embracing sustainable solutions in the built environment is of urgency in the battle against climate change [1]. Leveraging the built environment is one of the key solutions to address the climate emergency challenge as the building and construction sector is widely acknowledged as the main contributor to climate change. The sector accounts for nearly 30% of the worldwide greenhouse gas emission, 40% of energy consumption, approximately 12% of water use, and 40% of waste [2].

Sustainable development could reform the practice in the building and construction sector. Embedding the sustainability principles in the design and construction phases would future-proof our buildings and infrastructure projects against extreme weather events. This process requires careful thoughts of possible future events to devise appropriate sustainable strategies for optimizing the whole life value of buildings and infrastructure projects. Some important factors need to be considered in making our built environment more sustainable and resilient, such as flexibility and adaptability, resource use, weather resilience, life cycle costing, social transition, technology, and regulations. However, previous studies highlighted that performance gaps were still a common issue in achieving the sustainable built environment [2,3,4]. Many research questions had been raised, particularly from the perspective of overoptimism in setting the environmental goals or some performance gaps could be solved from the interplay between humans and the environment for delivering the sustainability goals. As a result, this perspective paper aims to highlight opportunities in optimizing sustainability performance in the built environment via human-centric approaches. The flow and structure of the paper begin with a review of sustainable development in the built environment. The following sections highlight performance gaps within the sustainable built environment and the associated opportunities from the human-centric approaches. The last section concludes the review with the key takeaway message of this perspective paper.

2. State of the Art in Sustainable Development in the Built Environment

The definition of sustainable development originates from the Brundtland Report published in 1987. It is still widely accepted and referred to as “development that meets the needs of the present without compromising the ability of future generations to meet their own needs.” The principle of sustainable development should achieve a balanced and optimal development as per the principle of the triple bottom line, namely, the environment, society, and economy [5]. Sustainable development offers a more holistic, systematic, and long term-based strategy to design and construct buildings and infrastructure projects. Sustainable solutions set out the future proofing vision for the built environment by mitigating the negative developmental impacts throughout the project lifecycle. It is generally recognized that the sustainable built environment would preserve biodiversity, enhance circularity, save energy, reduce carbon footprints, minimize wastes, promote resource efficiency, and improve occupant health and wellbeing.

The growing awareness of sustainability has significantly increased the uptake of sustainable buildings and infrastructure projects. Various sustainable building certification programs or ratings have been developed to assist stakeholders in evaluating and benchmarking sustainable building performance in different regions for delivering sustainable development goals, for example LEED (US), BREEAM (UK), Green Star (Australia), BEAM Plus (HK), Green Mark (Singapore), Green Building Index (Malaysia), and so on. Approximately 31 sustainable building certification programs or ratings and 55 schemes have been adopted by more than 30 countries worldwide [6]. The proliferation of these certification programs has resulted in a widespread diffusion of various forms of the sustainable built environment (i.e., new construction, refurbishment, in-use, neighborhoods, cities and communities, etc.) across the globe. As of 30 December 2022, there are 158,415 LEED certified projects and 32,547 BREEAM certified projects.

In the early years, the majority of sustainable construction research studies were design-oriented, where they focused on the design of sustainable buildings to meet the designated goals [2]. These design-oriented studies offered a guideline to stakeholders and laid out a vision for the future performance of the sustainable built environment. Following the advancement of sustainable development research in the past, there has been a transition from design-oriented studies to operation-oriented studies. The operation-oriented studies, such as post-occupancy evaluations, serve as a systematic process to evaluate the actual performance of the sustainable built environment and diagnose building issues for improvement. In addition to the assessment of sustainable building design and operation practice, current research studies and professional practices also involve commercial, institutional, social, and behavioral factors. Obtaining more field test data and making a comparative evaluation appear to be a necessary move to achieve a better performance of the sustainable built environment, especially through Building Information Modelling as well as its integration with other advanced technologies [7].

The performance of the sustainable built environment is mainly considered in (but not limited to) three aspects: energy consumption, indoor environmental quality, and occupant satisfaction. The reduction of energy use is one the main drivers of sustainable buildings. Energy use per useable area is one of the effective ways to reflect the success of sustainable built environment based on the lower carbon footprints. Human factors are also taken into consideration when evaluating sustainable buildings and these include essential human comfort (i.e., temperature, lighting, acoustic, humidity, etc.), health necessities (i.e., air quality, water, etc.), convenience (i.e., human–building system interaction, service access, etc.), and other contextual factors (i.e., community, amenities, mobility, etc.) [8].

3. Emerging Challenges within the Sustainable Built Environment: Performance Gaps

The sustainable built environment is made up of a complex system with different constituents. The desired sustainability performance in the built environment relies on a combination of technical, managerial, and behavioral factors. In general, sustainable buildings outperform conventional buildings in their operating performance. The authoritative evidence provided by the United States Green Building Council shows that sustainable buildings generally exhibit obvious environmental effects. Previous studies [4,9] also reported a better performance in sustainable buildings in terms of operation and maintenance, cleanliness, furniture, health, and productivity.

However, some greater benefits of sustainable buildings are rebutted by other operation-oriented studies. The inconsistent results were mainly due to the varied performance levels in different regions without meeting the claimed benefits of the sustainable built environment [2,5,7,10,11,12]. These studies could have undermined the credibility of the sustainable built environment as a means of meeting the net zero targets and creating a more resilient living environment for all.

Scholars including Geng et al. [2], Khoshbakht et al. [4], and Zhao et al. [9] found no significant difference between sustainable and non-sustainable buildings in terms of indoor environmental quality and occupant satisfaction. Khoshbakht et al. [4] conducted a global comparison of sustainable building performance and found that the inconclusive evidence on sustainable buildings could outperform the non-sustainable counterparts. They detected a higher inconsistency in lighting performance, with almost 50% of research indicating no significant differences in sustainable and non-sustainable buildings. There was also no significant or negligible difference between sustainable buildings and their conventional counterparts in the noise and thermal comfort performance [4]. Interestingly, Khoshbakht et al. [4] noticed that the Orient (eastern countries, such as China and South Korea) generally reported a higher satisfaction in sustainable buildings, while variances were observed in studies from the Occident (western countries, such as the United States and United Kingdom). This evidence provides great implications of socio-economic factors affecting the occupant satisfaction of sustainable buildings.

The energy performance of sustainable buildings also received a great number of critics from researchers. Limited energy consumption data are available to the public for validation, which leads to challenges in evaluating sustainability performance at the beginning of the sustainability revolution in construction. Newsham et al. [12] found that nearly 28–35% of LEED certified buildings consumed more energy per floor area than their conventional counterparts. Goh’s work [10] reported a malfunction of wind turbines in generating renewable energy as planned in the green building during its operational stage. When compared with conventional buildings, sustainable buildings, overall, failed to outperform in energy performance, occupant comfort, indoor environmental quality, greenhouse gases emission, and workplace productivity [9]. The study of Geng et al. [2] also revealed that the actual energy use of sustainable buildings showed a huge variance and some of them performed worse than conventional buildings, as well as the baseline. It was observed that sustainable buildings achieved less energy saving than expected and some differed markedly from the initial design [2].

Some studies also found that designers are overoptimistic in interpreting test results obtained in laboratories to real settings. Zhao et al.’s study [9] also revealed that the actual performance of sustainable buildings was not as expected when compared with their design targets and baseline modelling, thereby confirming rebound effects of sustainable buildings. They found that LEED certified buildings did not have any effects on energy consumption reduction and greenhouse gases emission in terms of source energy, although the site energy saving was confirmed. Zhao et al. [9] attributed rebound effects before 2006 to ambitious environmental goals of designers and a lack of experience in establishing numerical simulation and rating systems. Meanwhile, biased samples and inappropriate methods and evaluation parameters were identified as the main reasons of rebound effects after 2006 [9].

In the same vein, Shi et al. [11] also implied that conflicts could arise among multiple objectives in delivering the sustainable built environment; these included significant overheating risks resulting from natural ventilation during summer, disturbance, a lack of privacy associated with open-space design, and high temperatures and a high level of humidity associated with sustainable buildings. Geng et al. [2] concurred that the high tightness of building envelopes for the sake of energy saving in sustainable buildings has increased the risk of poor indoor air quality and overheating in the transition seasons. Goh and Yang [13] also suggested that the use of centralized air conditioning systems for the improved energy efficiency of sustainable buildings was at the detriment of user-perceived control for thermal comfort.

4. Opportunities to Optimize Sustainability Performance in the Built Environment: Human-Centric Approaches

As suggested by the literature above, there has been an increase in the performance gaps of sustainable buildings, which could be due to the lack of consideration by designers in terms of the interplay between humans and the environment for delivering the sustainability goals [14,15,16]. The sustainable built environment is designed and built for people. The architecture, engineering, and construction sector prioritizes cost-driven and technology-centered design. The human element is excluded from the design of broader buildings and infrastructure systems [14,16]. Designers and builders should often focus on the building systems to meet energy codes, sustainable standards, and green guidelines, rather than on the building practicability, usability, and user satisfaction [15].

Nonetheless, opportunities to optimize the sustainability performance in the built environment should be reflected from the perspectives of humanistic needs and life cycle thinking [17]. The delivery of sustainable development goals within the built environment cannot be successful without the active involvement of people who use the spaces or facilities. The intimate relations between humans and the environment should not be neglected when designing and constructing buildings or infrastructure projects. As indicated by Zhao et al. [18], the technological advancement of green building systems contributed to 42% of energy efficiency while the remaining building energy was attributed to occupant behaviors. Hence, human-centric approaches were toned to consider holistic and well-leveraged solutions towards the sustainable built environment through human factors.

Sustainable buildings are designed, built, and operated in different socio-economic contexts. The incorporation of sustainable solutions should go beyond the simple consideration of building fabrics, whereby a delicate balance of environment, social, and economic principles is emphasized. Much research within the domain of the sustainable built environment has largely focused on improving the environmental impacts, such as building energy systems, building envelopes, green materials, etc. However, sustainable building research should not be limited to energy performance-oriented or carbon footprint-oriented studies, but should also involve people-oriented studies [9].

Human factors relate to all quality functions required within the sustainable built environment, in which human behaviors, perceptions, and values are strongly correlated with the management and operation strategies of sustainable buildings [13]. Humanistic needs are of concern in determining the success of the sustainable built environment. However, there has been little research investigating the implications of human factors or human interfaces within the context of the sustainable built environment [15]. Although interface design has a wealth of research in industrial design and computer engineering, human–building interfaces are not exhaustively examined in the existing literature [15]. Behavioral interventions of users are important to encourage energy-efficient behaviors in the sustainable built environment, where the appropriate human–building interface is critical to maximize the sustainable outcomes.

Due to the increasing complexity of managing sustainable buildings, the direct control of some basic functions or building services is intentionally removed to recognize the building performance, hence impacting usability and the ultimate user comfort and energy performance [15]. Poor human–building interfaces can, however, lead to energy-intensive behaviors and violate the original intent of the building [15]. It is, therefore, essential to understand the human–environment interactions and identify the synergic influences of various triggers in the sustainable built environment.

Research Framework on Human-Centric Solutions

Generally, human-centric approaches revolve around human needs, interests, cognitions, attitudes, and behaviors, which will help to improve occupants’ interactions with building systems for better usability, functionality, and user experience. By understanding human needs and demands, human-centric solutions would offer more opportunities to empower users to harness sustainable features effectively. More human–building interfaces would be allowed in human-centric design solutions for increased user engagement, thereby improving the user ability to adapt to the environment in accordance with dynamic changes of physical, physiological, and psychological needs [16]. Localized energy use and comfort models can be created to shift the operation of the sustainable built environment from centralized control to individual control [2].

Figure 1 illustrates four main principles of the framework of human-centric solutions: (i) resilience and adaption to climate change, (ii) inclusive design and accessibility, (iii) flexibility, and (iv) seamless interactions and connectivity. The framework intends to enable a human-centric transition in the built environment to increase its ability of resilience and adaptation to the climate change. The sustainable built environment must be sensitive to local topography, culture, and climate conditions for improved resilience. Adaptation strategies should be considered by identifying risks and critical elements for necessary adjustments in the built assets. Human-centric solutions would enhance the capacity of communities to cope with challenges and mitigate the fallouts of climate change. Provisions are in place in sustainable buildings to accommodate likely technology advances and people’s evolving lifestyles without significant decommissioning costs. Concepts such as design or disassembly, deconstruction, and recyclability are incorporated as a sustainable strategy to enhance the reusability and recyclability of buildings and infrastructure projects. These innovative waste management strategies can reduce the landfill burdens and carbon footprints, but more importantly, they also provide potential savings on disposal fees and demolition costs.

Human-centric solutions help to address social needs by placing humans at the center of building planning and design. They facilitate an inclusive design to protect the vulnerable groups, such as the aging and disabled populations, from adversity. For example, human-centered design solutions would consider socio-demographic characteristics of users at different levels (local, regional, and national) and methodically map strategies for climate risk exposures and vulnerability of vulnerable groups. The built environment can then be designed in a way to assist vulnerable groups to adapt to unpredictable changes due to urbanization and social transitions.

Furthermore, human-centric solutions incorporate flexible design and access to public amenities to mobilize communities and promote human well-being and health in events of adversity. Sustainable solutions give allowances to diverse and specific needs of communities, while recognizing community tolerance and changes over time. Flexible design layouts (such as moveable partitions, multi-purpose spaces, open plans, high-capacity service voids, etc.) are incorporated in the sustainable built environment to cater changes in operational requirements to avoid obsolescence. The provision of easily access to public amenities and services in the vicinity is also integrated into the sustainable urban infrastructure context to cater the varying needs of communities to adapt to new technological and social challenges over time.

Human-centric solutions offer an opportunity of constant communication to users for active engagement. Humans play the role of active participants in sustainable built environments. Integrating technology equipped with sensing, inferring, and communication abilities makes the built environment more perceptual and cognitive, thus establishing a seamless connection between humans and the environment [19]. Technology incorporation would enable a greater personalization of managing spaces in the built environment. Open collaboration platforms that are facilitated through technology interfaces would help to enhance human capabilities to adapt and respond to the dynamically changing environment. In addition, building data is collected, analyzed, and modelled to identify activity patterns and human preferences, thus offering a better understanding of the complex intersections among diverse features in the built environment for delivering the sustainable development goals [19].

Figure 2 illustrates a conceptual framework showing human-centric solutions sitting at the intersection of gaps and opportunities of sustainable built environment research. Human-centric solutions can act as an umbrella initiative to confront the challenges of undesired human behaviors, cost-driven design, and technology-centered design in the current sustainable practice. On the other hand, the infusion of human-centered design in the sustainable built environment would also call for more opportunities in future research in terms of goal-driven design, user empowerment, and improved system efficacy. As human-centric solutions promote a greater understanding of human needs and social values, sustainable design solutions can be made to be more goal- and humanity-driven. The adoption of human-centric solutions could help to increase the awareness of people to engage with environments, hence empowering users to take part in the decision making of sustainable built environments (e.g., through the demand of end-users [20]). With more human control and context-aware operations, the system efficiency and self-efficacy of the sustainable built environment can also be boosted.

5. Conclusions and Ways Forward

The paper has highlighted some meaningful perspectives that human factors shall be taken into consideration in sustainable solutions, especially from the aspect of social sustainability. This key dimension of sustainability should integrate with other sustainable solutions and connect people and nature by embracing dynamic interactions between users and the built environment.

Human-centric solutions would be instrumental in the transformation of sustainable built environments. Previous research highlighted performance gaps associated with sustainable buildings and infrastructure projects and their failures to meet the intended sustainable development targets. Meanwhile, some sustainable buildings were also reported to have no significant difference to outperform their conventional counterparts. Technological advances, rather than human factors, are often given more attention in designing the future of sustainable built environments. The missing link of humanistic needs in the sustainable built environment practice could be addressed via human-centric approaches, in which, human-centric approaches that hinge on empathy and humanity promote the mutual interactions between human and the built environment. They support bi-directional human–building synergies and improve the user ability to adapt to the environment. Human-centric approaches provide a bottom-up policy that can optimally satisfy life-cycle objectives of sustainable built environment, thus optimizing the building performance in meeting the sustainable development goals.

The proposed conceptual framework shows how human-centric solutions interweave the gaps and future directions of sustainable built environment research. There are significant opportunities presented by human-centric solutions to support positive human experiences by redefining the goals of engineered systems in the sustainable built environment. Incorporating human-centric solutions would ensure the optimization of sustainable building performance to think beyond energy use or carbon footprints and shift our focus from what we have traditionally pursued in the contemporary sustainable initiatives. If human-centric solutions are not incorporated from the start in the prevalent sustainable initiatives, our buildings and infrastructure projects will be constructed in obsolescence (social obsolescence) and we must then then pay life-long costs to counteract the impacts brought by climate actions and sociopolitical changes in the future.

In conclusion, this perspective paper offers new insights into exploring solutions to bring transformational behavioral change in the sustainable built environment. The research framework was developed based on the knowledge gained from previous research works. Empirical studies should be carried out to test the framework and verify the principles of human-centric solutions.