An HRV is designed to bring a continuous supply of fresh air into a home while exhausting an equal amount of contaminated air. HRVs use what is called a“sensible” heat recovery core. This special aluminum core transfers heat from the exhaust air stream to the incoming air stream. During winter fresh incoming air is tempered by the heat that is transferred from the outgoing air so you save on energy costs, while during summer, the incoming air is pre-cooled if the house is equipped with an air cooling system. These HRVs are equipped with automatic defrost mechanisms so even if you live in a cold climate you can use your HRV all year long.