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Oxford study proves heat pumps triumph over fossil fuels in the cold
(www.nationalobserver.com)
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Houses need fresh air and need to expel dirty air.
The dirty air is warm, while the outside fresh air is cold. With heat recovery ventilation, the heat is transferred into the incoming air and the exhaust air becomes cold. This warms up the air in a very efficient manner.
It can also be combined with a heat pump to extract even more heat out of the exhaust.