1. Definition of a Green Building
A green building is often defined as an energy-saving building, ecological building or sustainable building
[1][2][3]. However, there are many differences in green building definitions. American architects Paola Soleri and Ian Lennox McHarg stated that the concept of “green” is used to emphasize people-oriented and sustainable development to realize harmonious symbiosis among human, architecture and nature
[1]. It has been further stated that ecological systems and the natural environment have become design considerations in the early stages of construction, which is the root of green building. Several researchers have attempted to define what a green building is in order to mitigate misinterpretation of green buildings
[4][5][6][7]. Some scholars have identified a green building as a sustainable building or an intelligent building. According to
[5], the importance of distinguishing the notions “Green”, “Intelligent”, and “Sustainable” was highlighted. The green building is more related to optimizing designs by adopting renewable energies, passive building design technologies, as well as scientific and systematic waste management techniques to minimize waste diversion to landfills
[5]. The sustainable building can be regarded as an integral design, which more focuses on balancing environmental, economic, and social benefits over the life cycle of the asset
[8]. Dwaikat and Ali
[9] also claimed that sustainable building and green building can be used as interchangeable terms based on the scope, objective and context of the design, construction and operation of the building. However, there is still no unanimous definition of green buildings that is accepted by researchers and industry stakeholders across the world. Some definitions that have been proposed by organizations and individual researchers are provided in
Table 1. Based on the content and key characteristics of the green building described, definitions can be classified into three categories, which are general definitions (No. 1 and No. 10), energy and resource-focused definitions (No. 2 and No. 9), and comprehensive definitions (No. 3, No. 4, No. 5, No. 6, No. 7, No. 8). Through the summary, it can be seen that green building is not a simple concept that focuses on the building itself, but a comprehensive idea concerning people, society, the economy, and the environment through the entire life cycle of the building. Hence, designing a green building requires efforts from all involved sectors.
Table 1. Green building definitions and features.
2. Benefits of Green Building Implementation
2.1. Environmental
The benefits of green building for environmental performance will enable people to cope with serious challenges because of uncertainties in climate change scenarios. The building industry has a substantial influence on the environment, which is considered the most important element in mitigating the effect of global warming on humanity
[15][16]. The improvements of energy efficiency and environmental performance in buildings are the core of the green building transformation
[15]. The green building as a positive performance construction has a minimal impact on the environmental aspect, which can also reduce lifecycle environmental implications
[17]. Darko et al.
[18] further note that one of the major objectives in green building is to minimize environmental interference and construction waste. The treatment of construction and demolition wastes plays an important role in the development of sustainable building design. The value of recovery rate in construction wastes should be over 90%, which can distinctly reduce the effect of waste generation
[19]. Moreover, the significant amount of waste from building can result in air and water pollution
[1]. Thus, the choice of building materials plays an important role in sustainable development, and could help to provide healthier and safer surroundings. Timber is an environmentally sustainable material for building construction that leads to reduced energy consumption and CO
2 emissions
[20].
The life cycle of building construction is associated with energy consumption and greenhouse gas emissions
[17][18][21]. The building industry is a “resource-intensive industry” that annually consumes huge quantity of energy and natural resources, including over 40% of energy, 40% of raw materials, 16% of water, and 25% of timber consumed worldwide
[17]. It has been further demonstrated that over 40% of worldwide greenhouse gas emissions are from the building industry. The green buildings have great advantages over traditional buildings, usually bringing higher performance embodied in energy conservation, water conservation, and CO
2 emissions reduction
[18][19][22]. In fact, the green building can be considered as the specific presentation of energy efficiency and resources efficiency. Architects, along with increasing awareness of climate change, should recognize the energy performance of building designs. Sustainable buildings can conserve 40% more energy compared with traditional buildings, increasing energy efficiency and decreasing CO
2 emissions, which signifies that the design should make room for conserving energy and reducing emissions
[18]. Additionally, the low-carbon materials in green building have been demonstrated to reduce life-cycle emissions of buildings by up to 30%
[23]. Therefore, the green building can be used to realize the sustainable development of low-carbon construction. It is typically designed to achieve the goal of high environmental performance, which can be evaluated through green building tools such as LEED certification
[17]. Zuo and Zhao
[17] mention that commercial buildings would benefit the most from LEED certification, followed by residential and public buildings. Besides, the energy consumption of buildings in urban areas can be made quantitative by applying a spatial regression model to analyze the connection between building greening rate and surface temperature
[16]. Furthermore, green building can also contribute to the enhancement of urban biodiversity and the protection of ecosystems through sustainable land use
[24][25].
2.2. Economic
The green building can lead to significant economic savings by improving life cycle cost (LCC) methodology and application, particularly from construction, maintenance, and operation sections. LCC includes the entire cost including building design and construction, building maintenance and operation, and building disposal
[24][26][27]. Technically, it follows the principle of engineering economics and can be used to complete life cycle budgets involving environmental and social costs during the building’s life
[17]. There is a definite relationship between cost savings and enhanced building performance from a life cycle viewpoint
[27]. Energy consumption can be an important characteristic during building design and construction. Therefore, the focus of energy conservation research has been to assess the degree to which green buildings reduce energy consumption compared with conventional buildings that comply with regulations. Lin et al.
[28] investigated the energy consumption of green buildings in China and found that in hot summer and cold winter regions, the average total energy consumption of Type A buildings (mixed mode) and Type B (mechanical conditions) green buildings is close to the recommended values of 60 and 80 kWh/(m
2a) in the Building Energy Consumption Standard and the energy consumption of green buildings is statistically significantly lower than that of conventional buildings, with the average energy consumption of Type A buildings (mixed mode) and Type B (mechanical conditions) green buildings being 15% and 23% lower than the upper limit required by the Chinese standard, respectively. An average reduction of 16% in carbon footprint can be achieved for commercial buildings through executing energy efficiency methods to boost the life cycle cost performance of the green building
[17]. It has been explained that greenhouse gas emissions as a social cost have been monetized by carbon pricing. For consumers and contractors in residential projects, the initial investments of green building could be higher than that of traditional building; however, these investments can be paid monthly by dividends in the form of saving on electricity bills in long run
[29].
Cost savings in the maintenance and operation sections might be conducive to counteracting the prior cost of green building construction
[26][30]. The project life cycle cost analysis can be used to decide the applicable upfront cost in green building design
[24]. Moreover, cost savings by the reduction of energy consumption and less maintenance and operation costs are the major source of revenue for green building management
[31]. Zhang et al. also report that the aggregate operation costs consist of water and power utilities, common maintenance, grounds maintenance, garbage recycling, and cleaning costs. Fundamentally, periodic maintenance could extend the building service life to meet the lowest adequate level of performance, which is essential to identify the time range of the complete building life cycle
[24]. Once the time horizon in a building’s life cycle is estimated, green building costs such as operating parts can be calculated, which involves direct and indirect benefits because of resource utilization
[32]. The improvement of resource utilization can bring direct benefits from energy use intensity and bring indirect benefits from environmental protection, respectively
[32][33]. Meanwhile, green buildings should be furnished using advanced integrated strategies and technologies. Optimizing sustainable buildings’ operating costs can be done through two approaches: passive design and active design
[29][32]. Passive design is the use of airflow and sunlight to provide a relaxing indoor atmosphere while reducing the energy demands of heating, ventilation and air conditioning (HVAC) equipment. Active design is the application of advanced technologies and systems to improve energy efficiency and reduce the resource consumption of building operations. The passive design has evolved along with active design, using advanced technologies to promote the use of sunlight and airflow to reduce the building’s energy demand.
2.3. Social
The social benefit of green building contains corporate social responsibility. Environmentally friendly management might achieve social benefits under the emerging idea of ecological development. One of the main drivers of green building is the demand for corporate social responsibility
[26][32]. Numerous companies take voluntary actions to conduct environmental issues such as reducing greenhouse gas emissions as part of their corporate social responsibility, a common situation in Japan
[32]. The improved corporate social responsibility can likely promote the creation of a good corporate image in order to develop green construction and sustainable building renovation. Companies in the oil and construction industries that rent or buy a green building might indicate their corporate commitment to the environment and obedience to corporate social responsibility, which can help the enterprises to obtain higher corporate reputations and indirect financial interests. Investors who accept green standards in the project’s construction can gain preferential land prices from the local government
[17]. It has been further claimed that improving corporate reputation could also make it easier for companies to attract investors. Therefore, the capital costs of companies can be reduced because of the preferable corporate social responsibility performance. Additionally, competitive markets in green building will be formed to effectively stimulate the development of green and sustainable buildings
[34].
2.4. Health and Safety
There are other benefits associated with health and safety if occupants move to green building. Indoor environmental quality (IEQ) is the most critical component of human benefits in green building, which includes lighting and indoor contaminants
[17][26][35]. Illumination distribution as one aspect of the indoor lighting environment can affect mental health and work efficiency
[17][32]. Indoor air quality plays an important role in the performance of building and participant health
[17][32]. Buildings could directly influence human health as residents spend most of their time indoors. The growing effect on cities in determining global environmental and health outcomes has led to a greater emphasis on urban policies to address human health
[26]. The green building can realize higher IEQ levels than traditional buildings, improving the health of residents and resulting in increased user satisfaction
[32]. Nevertheless, it has been also indicated that the attitude of indoor environmental quality from green building participants is more tolerant than that of traditional participants. Moreover, the sleep quality of occupants in green-certified buildings is 6% higher than that in non-certified buildings
[36]. Furthermore, energy savings should not come at the expense of health, which will help close the gap between customer expectations and design solutions for future green building developments. Meanwhile, many governments around the world imposed lockdowns during the COVID-19 pandemic to avoid the spread of the coronavirus. However, lockdown measures also caused widespread mental health problems among urban residents
[37]. Through the contribution of the Chinese national Assessment Standard for green building (GB/T 50378-2019) to the fight against COVID-19, Wang et al.
[38] found that green buildings can reduce the risk of infection and prevent cross-infection, promote people’s health, and maintain the stability of working life during the epidemic. The contributions of green buildings to the health of the population during COVID-19 are: (1) Green buildings control the concentrations of indoor air pollutants and promote the health of building occupants. (2) Mold can induce diseases such as asthma, allergies, rhinitis, and respiratory infections. Green buildings help to avoid the growth of mold and other pathogenic bacteria caused by dew and condensation on the building envelope, thus ensuring the health of occupants. (3) Green buildings can ensure the safety of water, avoid the health and safety risks caused by the wrong connection of pipes, and reduce the risk of cross-infection caused by the quality of different kinds of water. (4) Green buildings can benefit the health of residents through the use of green building materials with antibacterial functions.
2.5. The Summary of Benefits of Green Building Implementation
Overall, the implementation of green buildings can effectively reduce carbon dioxide emissions and energy consumption, and the recyclability and low carbon nature of the materials used in green buildings make them a practical solution to environmental problems, as shown in Table 2. At the same time, the life-cycle cost approach allows green buildings to save on electricity costs and thus reduce the cost of building occupancy. The use of green buildings can enhance the social reputation of companies and promote the formation of a competitive market for green buildings. Finally, residents of green buildings have better sleep quality, health and emotional stability.
Table 2. Sustainable benefits of green building implementation.