As Fantech's most compact, full-featured HRV, the VHR 70 unit brings a continuous supply of fresh air into a home while exhausting an equal amount of contaminated air. 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. The VHR 70 is equipped with automatic defrost mechanisms so you can use your HRV all year long.