The heat pump, no other heating method confuses as many people as to how it works as this. In reality, it’s only counter-intuitive as an idea at first and you’re more familiar with their operation than you think. In fact, you’ve probably been using one your whole life and not even known it.
The heat pump works by moving heat from the winter air outside your home, to the warmer air inside your home. How does that work? Well, it’s pretty simple, actually. Your AC unit, refrigerator, automobile’s air conditioner – these are all technically heat pumps. Only they’re working in the opposite way of what we mean when we say ‘heat pump’ when talking about heating. If your home AC unit has a heating function on it – then you have a heat pump. There is reversing valve on the unit that reverses the refrigerant cycle to bring warm air in and move cold air outside. And any air that is above absolute zero has heat energy in it that can be absorbed, leaving the air just a little cooler behind. (Though to be fair, your heat pump’s not going to work too well in that type of climate, or colder parts of the US.)
Another way to picture how the heating cycle works with a heat pump is to picture that the only thing you have to heat and cool your home with is a refrigerator. You know that on one side of the fridge cold air comes out and on the other side (back) there is a coil that gets pretty warm. So, you put the fridge in a specially-sized hole in the wall. In the summer, you’ll have the inside facing in. And in the winter, you’ll have the back facing inside.
The great thing about heat pumps is that their efficiencies are extremely high. This is because they’re not actually generating heat but rather moving it from one area to another. In some configurations their efficiencies can be over 350%! This adds up to a lot of savings on your heating costs.