Introduction
There is growth in the use of sustainable technology in building and construction industry in all part of the word. The term “sustainability” could currently be the most used term in this industry. Sustainability is motivated by realization that resources available for construction are becoming scarce day by day. The idea of sustainable technology has attracted a lot of attention from scholar, researcher, governments, and building and construction firms. The main aim of this attention is to come up with building technologies that conform to the principles of sustainability. One of the areas that have attracted a lot of innovation is Green building or Green house. There is a lot of innovation on architectural designs and constructions materials that aim at coming up with houses and houses that promote health and sensitive to environment.
Various scholars have dedicated themselves in addressing the ideal, principles and implementations of green building. The aim of this literature review is to review ideas on green house and focus on its contribution to sustainability.
Principle of Sustainability
The idea of sustainability is to leave the earth in as good or better shape for the future generations than we found it for ourselves. This idea have become more relevant today due to various effects witnessed due to increased pressure on natural resources leading to environmental effect. According to James Wines, human activity can only be environmentally sustainable when it can be performed and maintained without degrading the natural environment and depleting the earth’s natural resources. Natural resources are known to be limited; for sustainability, there should be control of use of these resources. In use of other resources, energy is needed. Currently almost every human activity, results in the consumption of energy in some way. Majority of energy is produced from non-renewable sources such as fossil fuels; depletions of such resources would lead to a major tragedy. Uncontrolled use of natural resources not only leads to exhausting our supply of resources for future generations but it is also degrading the atmosphere (Payne, V. 2007, p33). In architecture design of green house, these factors are considers in addition to the conventional focus on the optimisation of functionality and space utilisation.
Apart from concern for natural resource and environment, there is increased interest in personal health and environmental issues, sometimes also in the direction of sustainability (Reddy, V, 2004, p56). This interest is evident in the recent increase in demands for organic products. This increased demand on organic product is as a result of public concern for nutrition and health; leading preference of natural products that have fewer chemicals in them. Looking at sustainability, organic method is more sustainable since methods used use natural fertilisers and pesticides instead of chemicals from the earth, which takes up resources and use more energy. The same concerns are evident in construction industry where there is more demand for houses that promote personal health of individuals.
New Concerns for Sustainability
In the past building designs was more concerned with making more efficient use of land. It was also more concerned with creating more proving more residential housing for increased demand for housing. Although there was some concern for environment and sustainability, these concerns were overshadowed by necessity and space (Payne, V. 2007, p43). Inspired by the modernism and post World War socials ideas, a new wave of architectural designs came and converted cities from their earlier slum look to tall block buildings. Although this conversion was viewed as a success at that time, it is considered to be a great failure today. As it is now realised, the concept of needs was fulfilled the designs but the concept of limits was greatly exceeded (Liddell, 2003, p17). Although bring the population into the inner city does produce better sustainability in terms of the environment, due to less need for transport of humans and goods, it was not socially sustainable for human life (White, N, 2002, p56). High number of confined people in small space led to increase in stress and antisocial behaviour also producing higher levels of crime. There was fear that the new block of housed would be converted to slum in the future; a fear that became a reality. From this experience, there was a need for a balance between need, limit and other factors in sustainable designs (Green, K. and Vergragt, P, 2001, 63). Thus, principles of needs and limits are the foundation of sustainable architecture designs. The other values of aesthetic, socials, environment, and political, economical and moral concerns are used with these principles to ensure sustainability.
Green Building
Green building, a concept that is refereed to as going green in construction, integrate various sustainability concept to come up wait a building that minimize the impact of the building to environment. According to various literatures, the concept includes a variety of practices and innovative techniques that reduced effects of the building to the environment and human health. The most advocated thing in green houses and building is the use of renewable resources rather than those that could not be renewed (Reddy, V. 2004,). There is also concern for ability of the buildings to make utilize naturally available resources such as sunlight, and rainfall. For example, use of solar energy is emphasized instead of reliance on other uses. Both passive and active solar and photovoltaic technique are used make use of solar energy (White, N, 2002, p45). Material used in construction is chosen to have a good effect to the environment. For example, instead of using conventional materials for roofing, green roofs and green gardens are used (Reddy, V, 2004, p66). Instead of using conventional concretes, which is not renewable, permeable concrete or packed gravel may be used (Reddy, V, 2004, p903). Although effect on environment is the great concerns for green buildings, green buildings are not just a random collection of environmentally friendly materials and techniques but have to consider other basic requirements of a building (Loorbach, D, 2007, p78). The effect of complete cycle of the green house should also be considered while the overall effect and emissions of materials used in construction should is taken into consideration. On the other hand, when choosing the materials to be used in green building, it is taken into consideration that the overall effect should lead to reduced resource and energy use.
Although the main concept in green building is sustainability, the designs also considers the aesthetic effects of the buildings
There is a rapid demand for green houses as a way to sustainable environment. Thus, green building is rapidly gaining momentum as a protocol for design and measurement for a building environment. Precepts on sustainable building started to be used in construction some decades ago but it recently that the concept is being integrated in global building and construction industry (Reed, M, 2001, p77). Today many countries have green building rating system that give guidance and provide the best definition of a green building.
Green building is motivated by five basic concepts. According to New Directions in Sustainable Architecture and design, the basic five motivations is the driving force toward innovations in green building technologies. The main feature in green buildings is their ability to utilize the sun (Thompson, W. and Sorvig, K. 2007, p99). Both passive and active strategies are used tap solar energy. Unlike other source of energy, energy from sun is free, abundant and clean. Innovation in the used of photovoltaic cell has made it possible to effectively tap enough solar energy for use in the buildings. In addition to the technologies used to utilize solar energy, the designs of green buildings allow making the best use of sun for light (Loorbach, D, 2007, p113). The other concern is to improve quality of indoor environment of the building. With modernity, most people spend most of their time indoors. In fact most of the people spend a much as 90 percent of other daily time indoors. This makes it imperative to improve the indoor condition of the buildings. Urbanisation together with environmental degradations has led to severe environmental effects of most residents (Reddy, V. 2004, p901). Environmental related illnesses have been in increase in most cities. With most people spending most of their time indoor, improving the air condition of the building would not only improve health but also lead to more fulfilling life. The various causes of indoor pollution are considered in designing green houses while appropriate measures are taken to reverse the conditions.
In most literatures in sustainable building technology, sustainable use of land is identifies as one of the main concerns. In green building, there is concern on utilizing land in a sustainable way. Green building ensure that land is used responsibly to make optimum use of available land and also take care of the environment (Thompson, W. and Sorvig, K, 2007, p111). Earth natural resources are scare and exhaustible. Responsible use of natural resources for sustainability is emphasized in green buildings. Use renewable materials for both external and internal designs of green building in not only encouraged but expected. For example, internal design of the building would use renewable and reusable materials and also of durable quality so that they are not replaces more frequently. The materials embodies energy and their effect to the environment is also considered when choosing building materials (Lovert, H, 2005, p36). Performance and moisture resistance is taken into consideration in designing green buildings. In conventional building, maintaining a constant state of interior comfort usually leads to a lot of wastages and cost (Smith, A., and Stirling, A., 2005, p1451). The wastages and cost are prevented or minimized by use of green building technologies. The average energy loss of a conventional house is usually more that three times higher than energy loss in a green building.
Effectiveness of Green Building
Use of Green Building principles lead to integration of high performing technologies in the building. When various high performing technologies are well integrated, the end result is a building that is both environmentally friendly and healthy (Hooper, A, 1999, p89). The end result of a green building should lead to reduction in energy use and also reduce repair and maintenance cost. Although the effects of environment are not easy to evaluate, green buildings are expected to lead to improved indoor environment. Green buildings also lead to lower contribution to environmental pollution of the surrounding (Robert, J, 2004, p33). Above these advantages, there are also claims that high performance in green building may have positive effect on productivity. It is claimed that green building increases workers productivity and retail sales. Beyond environmental and health effects, green building can also have a fiscal impact. The example given for fiscal impact is that widespread used of green roofs and green gardens may reduce amount of money used in storm sewerage.
Despite of strong arguments made for the benefits of green buildings, evidence to support the claims are not easy to get. The main setback to support of green building is that it is based on projections of possible buildings rather that availability of historical data to support the claims (Lovert, H, 2005, p37). One of the claims that are us not easy to proof is the claim on green building contribution to workers productivity. However, data on financial impact of green building can be obtained and objectively evaluate. According to literatures, architects, engineers and green building constructor could convince client to adopt this technology by providing them with objective information on fiscal impact of green building.
There are various literatures that link design of a building with productivity of workers. Building designs such a green buildings are shown to affect employee productivity by use productivity measures such as absenteeism, sales or employees overall turnover. Children interest in school has also been used to measure the effect of building (Robert, J, 2004, p21). Available literature shows that environment created by green building leads to high performance in employees and an increased in interest in school by children. These results together with sustainability effect are very useful in support of green building.
Economics of Green Buildings
Despite of the benefit that can be obtained from green building, there is general reluctance to use green technologies due to the cost involved. In most countries most of the green building projects are talked by the government. The explanation given to this trend is that financial impact of green building is minimal to governments as compared to private investor (Edwards, B, 2003, 67). Thus, most of green building are financed, operated and owned by government agencies. Despite of this, there is increase interest in green building among private investors. For example, major firms such Ford Motor, Honda Toyota and Hines Developments have taken projects in green buildings.
The cost to green buildings can be divided into three major parts tarts that contribute to the total cost: cost of site, direct and indirect construction cost. Site acquisition cost is the cost involved in acquiring the site where a green building would be constructed (Edwards, B, 2003, p78). Various considerations are involved to ensure that the site of the green building ensures that basic environmental and sustainability elements are considered. For example, LEED recommend that the site should be near a public transportation and sensitive to water quality a run off (Percio, S, 2009, p36). The site should also ensure that the building will have a constant access to sunlight and natural ventilation.
There is no evidence that the site for green building is more costly that the costs of conventional buildings. The difference noted from literatures is that a green building site require more inspection that that of conventional sites. Direct cost is the cost that is directly used in construction of a green building (Hawthorne, C., and Stang, A, 2005, p98). Evidence shows that direct cost of green building is not necessarily higher that direct cost of conventional buildings. For example, the construction of new DPR Construction Building in United States led to an increase in cost by only 1 percent. On the other hand, The City of San Diego Ridge haven Building led to 53 percent energy conservation. Indirect cost of green building such as that of consultation is constantly going down as more professional are engaging themselves in green building technology.
Conclusion
Global environmental crisis witnessed in the world today is a call for more concerted effort to conserve the environment. There have been responses to environmental call in building and construction industry through use of sustainable building technologies. Sustainable building technologies appreciate the need to conserve resources and environment for future communities. Green building is one of the areas that have taken a bigger step in sustainability. Green buildings conserve the environment by use of environmentally friendly designs and materials. This method makes better use of natural resources such as solar energy leading to conservation of energy. Although green building seems to be slightly expensive to construct, they are energy and cost effective in the long run.
Reference list
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Green, K. and Vergragt, P, 2001”Sustainablity at Millennium: Globalization, Competitiveness and Public Trust. Global issues.22 (7), p 63-65.
Hooper, A.1999 “The design and planning of residential development: house types in the speculative house building industry”. Environment and Planning 51(11), pp53-58.
Liddell, R.2003 “Eco-minimalism: getting the priorities right”, Building for a Future12 (4) pp12-17.
Jones, B. 2002 “Building with Straw Bales: A Practical Guide for the UK and Ireland” Green Books, Totnes.
Reed, M. 2001, “Fight the future! How the contemporary campaigns of the UK organic movement have arisen from their composting past” Sociologia Ruralis 41,(1) pp131-145.
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Hawthorne, C., and Stang, A. 2005 “The green house: new directions in sustainable architecture”. New York: Princeton Architectural Press.
Robert, J. 2003. ”Good green homes”. London: Gibbs Smith.
Thompson, W. and Sorvig, K. 2007. ”Sustainable landscape construction: a guide to green building outdoors”. London: Island Press.
Edwards, B. 2003 “Green buildings pay”. New York: Taylor & Francis.
Percio, S. 2009 “The Green Tragedy: LEED’s Lost Decade”, Green Real Estate law journal, 33 (22) pp 33-35