A heat recovery system works (also called HRV or MVHR) via a heat recovery ventilation unit which is usually located in the attic, roof space or plant room of a building. Rather than just extracting air and replacing it with the air from outside, a heat recovery system draws the heat from the extracted air and passes it to the air which is being filtered in from outside. The extract and supply air do not flow within the same pipes and there would be no cross contamination of the different air flows. The heat recovery unit is connected to room air valves via a network of ducting throughout the building.
With a heat recovery system, you make use of what already exists as well as re
