[brendoelfrendo]

I guess I lucked out; our house had a (very old) whole-home (that is, ducted) heat pump system for heating and cooling when we moved in. When it was time to replace, our local contractor knew exactly what we needed. They even do mini-splits, had we wanted one.

[Glyptodon]

Do newer ones somehow not need ducts?

Edit: (or so you mean mini splits?)

[brendoelfrendo]

No, no ductless magic without mini splits. I feel like a lot of people refer to heat pump systems interchangeably with ductless mini splits, so I wanted to clarify that. Maybe that's just an issue with the people I speak with, though.

[notyourwork]

You are right. Most do heat pumps with mini splits for each zone. However, ducted houses can certainly use heat pumps with an air handler. Typically this translates to heat pump replaced outdoor condenser (ac unit)and the air handler replaces the indoor furnace.

[rootusrootus]

> the air handler replaces the indoor furnace

If the furnace is a serviceable natural gas unit, keep it. It makes a better backup than strip heat.

[Glyptodon]

I'm just much more used to seeing air handler style, particularly for situations that aren't additions.

[slumberlust]

What's the difference? They all work on the exact same closed loop evaporation cycle no?

[nkurz]

Yes, the actual refrigeration and heating cycles are always based on compressing and decompressing a gas. But the gasses used differ based on temperature range, and further you can have air to air, air to water, or water to water for the heat transfer. The overall costs are the system can be very different based on whether you have a split unit that requires a single wall penetration, a central unit in the basement with ducting, or a geothermal system that requires digging deep trenches or wells. It makes for difficult conversation when some people are talking only about air to air minisplits when others are including all of these and more.