According to the United States department of energy (US DOE), 43% of the energy used by the average home goes toward heating and cooling the living space.
This is more energy consumed than any other system in the house, followed by electrical applicances, lights, and water heating. This is why the US DOE encourages people to upgrade their heating and air conditioning systems, as well as to get proper insulation, because this could reduce the costs of heating and cooling by up to 30%.