Traditionally popular in warmer climates, air-source heat pumps (ASHPs) are now being installed in just about every climate zone in the U.S., as consumers have often found them to be a cost-effective way to supply the majority of their heating and cooling needs. That being said, many ASHPs can struggle to provide a comfortable level of heating when the outside temperature falls below freezing, which is why units are often equipped with a backup or supplemental heat source — typically electric resistance heat (strip heat).
Supplemental heat is usually activated when the thermostat senses the outside air temperature is decreasing, and the ASHP can no longer keep up with the heat loss from the home. Backup heat can be expensive to use, which is why it’s important to find the right temperature — the balance point — at which compressor operation stops and supplemental heat is activated. However, that specific temperature can vary, depending on the cost of electricity in a particular location as well as the homeowner’s preference for lower energy costs or better comfort. As such, it’s up to contractors to figure out which balance point will work best for their customers.