Answer:
The energy conservation through energy efficiency in the building has acquired prime importance all over the world. The four main aspects for energy efficiency in a building include first and foremost the nearly zero energy passive building design before actual construction, secondly the usage of low energy building materials during its construction, thirdly use of energy-efficient equipment for low operational energy requirement, and lastly integration of renewable energy technologies for various applications. These aspects have been discussed along with their economics and environmental impacts briefly in this paper.
The first aspect is related to the prior design before the construction of solar passive building techniques adapted all over the world not only for passive heating/cooling but also for daylighting the building. The second is utilizing the low embodied energy building materials for building construction. The third aspect deals with operational energy conservation using energy-efficient equipment in the building. Lastly, the building has to include the utility of integrated renewable systems for hot water heating, solar photovoltaic electrification, etc.