By identifying and implementing the means to achieve energy efficiency and savings, not only can energy savings be achieved, but also equipment/system services life can be extended and indoor quality may be improved. All these mean savings in money, and possibly, improved productivity. Based on the principle of ‘The less energy is consumed, the less fossil fuels will be burnt’, both the buildings and the power generation companies will generate relatively less pollutants and by-products. Therefore, all parties concerned contribute towards conserving the environment and enhancing sustainable development.

In this scenario, the introduction of the energy efficient building design concept has become critical for achieving the collective objectives of energy security and environmental protection which, in turn, can ensure economic and social development.

Energy efficient building design is essentially an integrated approach. The available options in architectural intervention, building materials, available technologies and design methodologies need to be carefully evaluated to minimize energy usage and provide cost-effective solutions. The purpose is to achieve total comfort with the least amount of conventional energy input. This would save scarce fossil resources and result in concomitant environmental benefits. Not only can the new building stock be targeted, but also retrofitting of the existing buildings with newer technologies can result in reduced energy consumption in a large number of cases. The various options available for achieving the above objectives are as follows:

Passive solar techniques capture adequate solar energy to heat the building during winters and provide for shade from the sun during summers. The initial approach is to provide a suitable orientation with respect to the sun. Vegetation, overhangs, awnings or sunscreen accomplish optimum solar designs. To reject heat in a hot climate, natural sinks are used and ventilation, wherever required, is maximized. The useful daylight is harnessed through appropriate windows, skylights and light shelves.

Increasing insulation levels in conditioned buildings is regarded as the most cost-effective investment in energy efficiency. Thermal insulation of external walls, roof and floor and double pane windows can reduce energy consumption for space heating by lowering heat losses through the envelope of the building. Energy consumption for cooling can also get reduced because of lesser heat gains from outside, through the envelope.

Energy efficient lights consume considerably less electricity than an incandescent lamp for producing the same light. Its initial cost is high but it lasts for a longer duration and the running cost is less. Such lamps are now available in a variety of wattages. As electricity is efficiently being converted to light in these energy efficient lamps, the amount of heat generated is significantly less.

Solar water heaters currently available in the market generate hot water at 60-80° C and can be installed conveniently. The technology is fairly mature and economically viable. It can affect considerable saving of electricity. The technology has already found success in market penetration in western and southern parts of India. Solar air heaters can supplement the heating requirement of a building during the day. In cold and sunny weather, these can be used extensively to reduce the demand of electricity and firewood for space heating. Old buildings can also be easily retrofitted with solar air panels.