In which type of conditions must heat pumps with electric resistance heaters function?

Heat pumps with electric resistance heaters are designed to function efficiently in conditions where the outdoor temperature drops below the balance point. The balance point is the temperature at which a heat pump can meet the heating demand of a building solely through the heat it extracts from the outside air. When the temperature falls below this point, the heat pump's efficiency decreases, and it may struggle to provide sufficient heating on its own.

In such scenarios, electric resistance heaters are used to supply the additional necessary heat to maintain comfortable indoor temperatures. This approach ensures that the heating system can effectively address the heating demand even in extreme cold conditions, thus providing a reliable solution during harsh winter weather.

While heat pumps can operate in a range of temperatures, relying solely on their typical heat exchange process becomes inefficient below the balance point, making electric resistance heaters a valuable supplementary feature in these situations.