It could collect the waste heat from the ventilation air and uses for hot water heating.

* circulaton pump, flow control, electronic expansion valve inside
* the exhaust air heat pump extracts air via ductwork connected to the warm areas of the building such as bathrooms, kitchrooms and utility rooms. Heat is removed from the air and transferred into the heat pump's refrigerant circuit before being discharged to the outside.
* ventilation, which means totally hygienic inside air, is a basic requirement for living in a healthy house.