A heat pump can move three units of heat for every one unit of electricity it consumes, which is why it runs far cheaper than old electric furnaces.
Modern cold-climate models work well below freezing, so the old worry about heat pumps failing in winter is mostly outdated.
Size the unit correctly with a proper load calculation, since an oversized pump cycles too often and wastes energy.
Pair it with better insulation and it handles both heating and cooling, replacing two appliances with one.
The efficiency gain is largest when it replaces old electric resistance heat.