Anyone who's opened an eye-popping energy bill in the middle of winter or one for air conditioning in the summer has probably wondered which system costs more to operate. According to analyses, it's no comparison: heating your home requires four times more energy in the US than cooling your home.

Heating or cooling through conduction typically takes place at the building envelope (the outside walls, windows and doors) where warm or cold air outside causes the molecules of the envelope to increase vibration or decrease vibration which in turn causes a heat loss or gain inside of the building.

Air conditioning, often the most recognized part of HVAC systems, cools indoor air during warmer periods. It works by removing heat and humidity from inside the building and releasing it outside, using a system of coils filled with a refrigerant.