Globally the building sector accounts for more electricity use than any other sector. Withincreasing urbanization, higher in developing countries, the number and size of buildings inurban areas will increase, resulting in an increased demand for electricity and other forms ofenergy commonly used in buildings. More than 90 per cent of our time is spent in buildingsi.e. either in the office or at home. Energy used in buildings (before & after construction,residential and commercial) accounts for a significant percentage of a country’s total energyconsumption. This percentage depends greatly on the materials used in construction,processes used in construction, degree of electrification, the level of urbanization, the amountof building area per capita, the prevailing climate, maintenance operations, as well as nationaland local policies to promote efficiency.The energy efficiency of a building is the extent to which the energy consumption per squaremetre of floor area of the building measures up to established energy consumptionbenchmarks for that particular type of building under defined climatic conditions.
Buildingenergy consumption benchmarks are representative values for common building types againstwhich a building’s actual performance can be compared. Benchmarks are applied mainly toembodied energy of building materials, type of energy used, heating, cooling, airconditioning,ventilation, lighting, fans, pumps and controls, maintenance, office or otherelectrical equipment, and electricity consumption for external lighting. The benchmarks usedvary with the country and type of building.Investments in energy efficiency in a building can be compared with the cost of capitalinvestments necessary on the supply side of the energy system to produce a similar amount ofpeak capacity or annual energy production. Usually, the capital costs of efficiency are lowerthan comparable investments in increased supply and there are no additional operating costsof efficiency compared to substantial operating costs for supply-side options. In addition,energy efficiency investments generally have much shorter lead times than energy supplyinvestments, a particularly important consideration in countries where the demand for energyservices is growing rapidly.
. Reducing power and energy requirements in buildings reducesthe capital outlay required and the running costs of these stand-by systems. Hence paperreviews about an integrated system of energy efficient constructions procedures which helpsto optimise the overall life cycle cost of energy efficient buildings.