How much heat is recovered?
On average 90% is recycled but this can be higher. It is dependent on which type of heat exchanger is used, together with the difference between the temperature of the incoming and outgoing air, as well as the amount of moisture in the air. For example, if the outside air temperature is 0C and the internal air temperature is 20C, you can expect the fresh air being introduced via the system to be approximately 17-18C. For ventilation systems without heat recovery, the incoming air would be 0C.