A pump using exhaust air performs best in new passive and low-energy houses as well as in houses that use mechanical supply-exhaust or exhaust ventilation. Apartment houses built in the 1970s and 1980s typically have exhaust ventilation and shared exhaust ducts.

A pump using exhaust air recovers heat from exhaust ventilation. In renovated buildings, this heat can be utilized to warm rooms and domestic water while reducing the need to buy energy.

Carbon footprint: 30 g CO₂/kWh.