HVAC is an acronym that stands for Heating, Ventilation, and Air Conditioning. The term HVAC is used to describe a complete home comfort system that can be used to heat and cool your home, as well as provide improved indoor air quality.

This system provides whole house heating and cooling through one set of ducts, usually located in the roof space. Heat from the outside air is pulled into a central unit. From there it's blown through ductwork to outlets in the home. The air then returns to the indoor unit to be re-heated.

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.