We recently had our heater changed to a heat pump and whilst producing the same amount of heat, it’s also very energy efficient, using a good chunk less energy than our previous heater.
How do they work and how are they so damn efficient?
Aside from the more technical details about the refrigeration cycle, a heat pump is effectively an air conditioner run backwards.
When you run an AC unit, the coil in your air conditioner/furnace absorbs heat from the air stream and transfers it to the refrigerant (through phase change)…the refrigerant then goes to the condensing unit, where it condenses out of gas, expelling the heat absorbed, which is then radiated to the outside air.
With a heat pump, you’re taking heat from outside (yes, even when it’s cool or cold, there is still heat in the air outside), transferring it to the refrigerant, and then the heat is radiated inside the coil in the fan airstream…so you take heat from outside and bring it inside.
This is also why heat pumps lose efficiency when things get REALLY cold. It becomes much harder to extract heat from outside when it is extremely cold outside, plus the need for heat inside is much higher, and so the heat pump can struggle to keep up. This is also why a lot of heat pump systems in very cold climates use supplemental electric heat (or gas heat) to compensate for the drop in heating ability.
