Blows my mind every time I see someone talk about heatpumps like it’s some state of the art technology on the bleeding edge. My heatpump is so old it’s plastic has yellowed like an 80s computer.
What changed is the commercial availability of ones suitable for colder weather.
Heatpumps are not some sort of witchcraft, we’ve had refrigerators for like a century. They are a heatpump system.
People think refrigerators create cold inside. You don’t magically make cold out of thin air, that would go against laws of thermodynamics. They actually just pump the heat out of the inside of the fridge and release it via heatsink on the back (or from the sides on newer models). It’s why they are called “heat pumps” coz they pump the heat out of something. And if you reverse the system, they just do the opposite, they bring heat inside and release cold on the outside, which is what we usually use for heating.
They make no sense on the grand scheme, but they work really well in enclosed environments where each side of it is separate from the other. Except in heatpump tumble dryers where they actually work great connected. Hot side evaporates moisture from clothes which then condenses on the cold side of the heatpump. All in a single enclosed loop.