[londons_explore]

The efficiency of electrical resistance heating is exactly the same whether you use motor coil resistance or resistance wire.

However, they simplify their system design a little (fewer contactors, fewer wires, fewer components to buy/test)

[stavros]

It's not the same if you generate the heat outside and bring it inside, though. I don't know enough about where the fan is located to know if that's what you mean, but that would be different.

[londons_explore]

air/air heat pumps have a fan on both the inside and the outside. In modern designs, both those fans will be brushless DC, which enables deliberate heating through software.

Note however that both fans will typically be ~150 watts - which means that when heating they can't produce orders of magnitude more heat than that. So heat produced by the fan motor, even when run to generate as much heat as possible, probably won't be a very significant contributor to overall system heat output.

[raccoonDivider]

Logically you'd keep as many parts as possible inside, where the temperature is easier to control?

[bogeholm]

Maybe if you expect the heat pump to mainly move heat in, the heat generating parts should be on the inside, and reverse if you’re mainly moving heat out (A/C).

Don’t know if this is considered during installation?

[briHass]

The compressor is the only component that generates a substantial amount of heat. That's really it's purpose: trading a pressure increase in the refigerant for a rise in temp.

The compressor is usually in the outdoor unit, because of noise, size, and proximity to the controls. It also is the item that consumes most of the power, so for minisplits, the outdoor unit is the part wired for high currents. It usually is wrapped in a nice insulating blanket (for sound as well), and vapor injection techniques used in cold climate pumps means the heat wasted is minimal.