3 ms·
Some heat pumps are rated for much lower temps.
by notyourwork 1y ago
Some heat pumps are rated for much lower temps.
- kragen 1y agoThey can work at lower temperatures, but they do need the auxiliary heat to deice the outside coils.
- srjek 1y agoIt's my understanding that nowadays most heat pumps have a defrost cycle where they automatically run in reverse for a bit with some or all fans off
- kragen 1y agoI think that may be how it works, yeah.
- sgerenser 1y agoWhen it’s running in reverse then it’s acting as an air conditioner blowing cold air into the house. So usually the heat strips are used then to reheat the air and prevent it from blowing cold air in the middle of winter. Not strictly necessary but most people demand it.
- eldaisfish 1y agoauxiliary heat is a separate heat source for the indoors. Most cold climate heat pumps run a defrost cycle to melt ice off the outdoor unit. that's different from auxiliary heat.
- kragen 1y agoI see!
- ip26 1y agothe aux heat comes in because their output is a multiplier. At 30F, perhaps they produce 4x the heat as the electricity put in. At 0F, perhaps they produce 1.8x the heat. This means the output declines with temperature, until eventually they don't produce enough heat to hold temperature. Enter aux heat. Cold weather heat pumps help because they stay above 1x for longer, but you also wind up needing to oversize a bit.
- kragen 1y agoThank you for explaining!