We have a Nibe F470 air-to-air. Most of the time it's as loud as an old fridge. Not something you notice, since it in its own small room (where the gas furnace

We have a Nibe F470 air-to-air. Most of the time it's as loud as an old fridge. Not something you notice, since it in its own small room (where the gas furnace used to be). When it's freezing outside and the heat pump is working hard, it is louder, but you'd also hear the gas furnace under such circumstances. I think by and large, it's more quiet than the gas furnace we had before.