*2.3.3 Energy and environment*

Energy efficiency leads to important social benefits, such as reducing the energy bills for poor households [35]. Power generation is generally the most expensive feature to add to a building. It is a major challenge for green building development in Nigeria according to literature, 40 million litters of petrol is consumed daily for private generation of electricity [36]. Surprisingly, green building development produces a high-performance building which uses less energy. Hence, its adverse impacts on the environment (air, water, land, natural resources) is minimized through optimized building siting, optimized building design, material selection, and aggressive use of energy conservation measures. The resulting building performance exceeds minimum International Energy Code (IEC) compliance level by 30–40% or more. It maximizes the use of renewable energy and other low impact energy sources. Embodied energy makes up to 30% of the overall life cycle energy consumption of buildings. Effective window placement for day-lighting is also employed to provide more of natural light against the use of artificial lighting during the day [37].

Residential customers sue up 64% of energy generated in Nigeria, 27% commercial with 9% used by industries. In the same vein, 50% of household power consumption is used for Heating, Ventilation and Air Conditioning (HVAC) compared
