In developed countries, about 40 percent of total energy generation is consumed by the building sector. The continuous improvement in the standard quality of living has inevitably given, and will continue to give rise to the energy needs of our buildings primarily for space cooling, space heating, provision of hot water, lighting and for use of electrical appliances.
This increase of demanded energy in buildings has led to a series of chain-consequences such as increasing consumption of fossil fuels, increasing CO2 emissions in to the atmosphere, worsening of the greenhouse effect and disruption of our climatic conditions; thus affecting environmental and economic sustainability. That is why the need of reducing energy consumption in buildings has been rendered of ultimate importance!
Green buildings – why we need them
To combat this environmental challenge, we need a holistic, integrated approach towards reducing the energy consumption in buildings yet maintaining a high standard of building services, internal comfort and quality of living. An integrated approach requires that every stage from conceptualization and design to construction and end building usage is ‘tuned’ towards reducing net energy needs.
Through this holistic approach we have managed to develop a framework, legislative, economic and social, for the promotion of buildings, and related practices, that will make the construction and buildings sector economically and environmentally sustainable. The notions of energy efficient buildings, net-zero-energy buildings, energy audits and energy certification of buildings which is based on a discrete measurable scale and standards, have made it possible to adopt common language in assessing the energy performance of our buildings and incorporating it amongst building specifications.
Elements of a green building
To reduce energy consumption in buildings we need to address the following main areas:
- Eliminate energy waste by applying proper building insulation, eliminating air and water leaks and avoiding poor quality in construction that leads to future damages and energy waste. Implementing proper insulation, ventilation and dryness to the building can help keep the heat inside during winter and prevent it from entering during the summer; thus reduce the amount of energy required to reach desired comfort conditions.
- Adopt a ‘greener’ lifestyle! The rational and efficient usage of energy is the logical continuation of having a green building and using it ‘according to spec’s! This means following some basic energy saving practices such as dressing up appropriately and according to season even while indoors, optimizing use of electrical appliances such as dish-washing cycles and switching off unnecessary electrical appliances. More sophisticated practices include installing automated power monitoring systems and purchasing energy efficient appliances.
Optimize energy gains from the immediate environment
- Incorporating bioclimatic principles and passive energy principles at design stage is a simple and relatively economical way to optimize the energy behavior of a building; bioclimatic design and passive energy principles aim at maximizing the potential benefits from the surrounding environment and using them towards achieving the desired internal conditions of temperature, humidity, lighting, air-quality towards visual and living comfort. In doing so, the amount of energy required to reach desired conditions is greatly reduced. Some simple examples of bioclimatic principles include considering the orientation of the building, incorporating design features such as openings with glass windows, shading features and light openings that will maximize solar gain in cold winter months and minimize them in hot summer days. Bioclimatic architecture may be extended to consider in-depth design features to take further advantage of climatic conditions and site features such as existing neighboring buildings, landscape features etc., while passive solar systems make use of materials’ thermal properties to exploit solar energy for the benefit of the building, e.g. thermal mass walls.
- Use renewable energy sources such as solar (solar PV and solar thermal), wind, geothermal or biomass energy. Renewable technology systems for buildings may be passive or active depending on how they operate; in general, passive systems (apart from passive solar construction elements) incorporate the use of simple solar water heaters for provision of hot water in buildings. More sophisticated systems (active) use renewable energy for space heating, and space cooling or for the direct generation of electrical energy. The use of renewable energy systems for generation of electricity in the building sector may be used to off-set conventional energy either through direct, on-site consumption or through distribution on the power grid.
The movement of green buildings has been well established into the minds of home and building owners as the rational building choice; apart from being environmentally sustainable in the long run, they offer considerable cost savings! Of course, the degree of sophistication incorporated into a green building varies considerably primarily due to budgetary constraints. The majority of new houses are built according to the minimum requirements of energy efficiency, which are enforced through legislation on energy performance of buildings by governmental authorities. However, beyond the minimum compulsory standards for energy efficiency, there are various financial incentives (e.g. using tax rebates or FITs) to motivate home owners to invest in more sophisticated systems that are economically viable on a longer term basis. However, In assessing long run financial viability it should be noted that various factors influence financial performance of these renewable energy systems (e.g. solar PV panels) such as climatic conditions, technology efficiency and financial incentives.
Incorporating solar panels on energy efficient homes is a movement further towards the idea of net zero energy buildings; “A zero energy building simply refers to a building producing the same (or more) amount of energy than what it consumes within a single year” . According to this definition a zero-energy-home uses renewable energy such as solar panels to generate enough electricity to cover for its total energy consumption for a year.
Regardless of the degree to which a building is energy efficient or uses alternative energy sources, green building practices are a reality and their concept is here to stay; apart from being the environmentally sound solution, through technological development and industrial advances, we have also managed to make it economically viable.