Abstract: An MVHR system for a building having a roof with at least two pitched slopes facing in different directions. The MVHR system comprises a Heat Recovery Unit (HRU) for exchanging heat between a flow of ambient air and a flow of air from inside the building. The HRU is connected to two ports located on different pitched slopes, and a flow diverter is provided between the HRU and the ports. The flow diverter is switchable so as to reverse the flows of air into and out of the building via the two ports and through the HRU. The system can be combined with photovoltaic solar cells and/or an air source heat pump and/or a ground source heat pump system.

Abstract: A Mechanical Ventilation Heat Recovery (MVHR) system for a building having a roof with at least two pitched slopes facing in different directions, the MVHR system comprising a Heat Recovery Unit (HRU) for receiving and exchanging heat between a flow of ambient air from outside the building and a flow of building air from within the building, the HRU being connected by fluid flow conduits to first and second ports located on different pitched slopes, in which a flow diverter is provided in the conduits between the HRU and the ports, the flow diverter being switchable between a first state in which ambient air flows from the first port to the HRU and into the building and building air flows from the HRU to the second port to be exhausted from the building, and a second state in which ambient air flows from the second port to the HRU and into the building and building air flows from the HRU to the first port to be exhausted from the building.