The human dimensions of energy use in buildings: A review
Renewable & Sustainable Energy Reviews
The "human dimensions" of energy use in buildings refer to the energy-related behaviors of key stakeholders that affect energy use over the building life cycle. Stakeholders include building designers, operators, managers, engineers, occupants, industry, vendors, and policymakers, who directly or indirectly influence the acts of designing, constructing, living, operating, managing, and regulating the built environments, from individual building up to the urban scale. Among factors driving
... erformance buildings, human dimensions play a role that is as significant as that of technological advances. However, this factor is not well understood, and, as a result, human dimensions are often ignored or simplified by stakeholders. This paper presents a review of the literature on human dimensions of building energy use to assess the state-of-the-art in this topic area. The paper highlights research needs for fully integrating human dimensions into the building design and operation processes with the goal of reducing energy use in buildings while enhancing occupant comfort and productivity. This research focuses on identifying key needs for each stakeholder involved in a building's life cycle and takes an interdisciplinary focus that spans the fields of architecture and engineering design, sociology, data science, energy policy, codes, and standards to provide targeted insights. Greater understanding of the human dimensions of energy use has several potential benefits including reductions in operating cost for building owners; enhanced comfort conditions and productivity for building occupants; more effective building energy management and automation systems for building operators and energy managers; and the integration of more accurate control logic into the next generation of human-in-the-loop technologies. The review concludes by summarizing recommendations for policy makers and industry stakeholders for developing codes, standards, and technologies that can leverage the human dimensions of energy use to reliably predict and achieve energy use reductions in the residential and commercial buildings sectors. Keywords Human dimensions; energy use; occupant behavior; building life cycle; energy performance; stakeholders Introduction Buildings have the potential to act as smart systems that facilitate the shift towards a more sustainable energy use paradigm  . They can encourage the accelerated uptake of renewable technologies and the reduction of energy use, carbon emissions, and operating costs while increasing the comfort, satisfaction, health, and productivity of building occupants  . While a substantial body of research covers the energy saving potential of improved building performance , the variable impact of identical energy conservation measures across different building examples is less understood  . An existing base of literature demonstrates that human factors may contribute substantially to this variance in energy use      . The main conclusion reached by these existing studies, which work across disciplines and are international in scope, is that technology investments alone do not necessarily guarantee low or net-zero energy, or higher comfort perception, in buildings. Indeed, humans factors also play a crucial role, and while the understanding of their impact has improved, it is often ignored in building design and operation. As an example, office occupants often work beyond typically assumed office hours, and such overtime occupancy drives the increase of internal heat gains due to the use of electrical appliances, lighting, and plug loads and extends the operation of building services such as Heating, Ventilation and Air Conditioning (HVAC) systems and lighting . Furthermore, not all occupants use building services at the same intensity. Researchers  demonstrated via computer simulations that occupants with a "wasteful" work style would consume up to double the energy of non-wasteful "austere" coworkers. It has also been widely demonstrated in experimental studies    that occupants vary in comfort preferences, satisfaction, and indoor environment perceptions due to physiological (i.e., gender and age), psychological, and cultural factors      . To the extent that these human factors impact total energy use, they contribute to prediction gaps  regarding energy expenditure and operating costs. Indeed, predicting human occupancy and energy-related behavior, which is stochastic in nature, is a challenging practice      . Accordingly, human factors in commercial buildings are considered a "dark side" of energy use  . In the residential sector, too, understanding the diversity of human energy use has been a topic of great interest    . For example, residential studies on this topic conducted in Europe [11,       , the United States [11,    , Asia      , and Australia    have demonstrated variation by a factor of 3 to 10 in household energy use that is attributable to human factors. Extended reviews have been performed on independent studies worldwide in an attempt to align these research outcomes and demonstrate the continued future need for studies on this phenomenon [9, 29,     . Taking a broader perspective, the human dimensions of energy use in buildings refers to an array of actions related to the building life cycle that include designing, constructing, living and controlling, operating, managing, serving, and regulating built environments from the building level up to the urban scale. The term "human" encompasses influencing roles from a variety of stakeholders that have an impact on the actual building performance, with a focus on energy consumption and occupant comfort. For this paper, stakeholders include building designers and owners, the technology industry and vendors, occupants, operators and managers, energy providers, and policy makers. The influence of these stakeholders on building energy use cannot be prescribed a priori, leading to inconsistencies between potential and actual building energy performance. Given the potentially broad impacts of human dimensions on energy use and the need to meet 2020 and 2050 energy and greenhouse gas reduction goals  , new data, guidelines, and models are needed to leverage human dimensions towards substantial building energy use reductions and improvements in occupant comfort that can be sustained across an entire building life cycle. In this paper, we argue that compliance with zero-net-energy buildings and other high-performance building guidelines  cannot be achieved without state-of-the-art methods for estimating human dimensions impacts on energy use at various stages of the building life cycle (design, operation, retrofit) and at various scales (zone, building, and urban level), both in residential and commercial buildings.