"but a heat pump requires a big unit placed outside the home that makes noise."

Old ones maybe. We've installed a Mitsubishi mini-split that can heat a 1900 sq ft. mediocrely insulated home in Appalachia (this morning was -6C). Never mind, the indoor spits (<30dB?), the compressor outside is so quiet you can't hear it if you're next to it. My, brand new, radon pump is far noisier.

As to footprint, the compressor is tall and wide (about 1m). But it's only 25 cm thick, so it doesn't take much room at all along the wall.

Really, Europe has no reason at all not to go all in with splits.