> Heating elements can run on DC more or less unmodified. ..but to get the same power (heat) output you need more current in a low voltage DC system. And power

> Heating elements can run on DC more or less unmodified. ..but to get the same power (heat) output you need more current in a low voltage DC system. And power loss in the supply cables scales with the square of current, so you'll need thick (expensive) wiring in the wall or you'll risk the walls becoming an equally effective heating element. Electric motors that run on DC are either brushed or have extra driver/conversion circuitry to pulse their coils in the right order. Both of these are not perfectly efficient.