Pretty much all gas water heaters are indoors in the US. I was worried about the electricity consumption of our heat pump water heater, but it's actually minimal.

The coefficient of power is like 5 or something, and, since it's a bit more expensive than a contractor-grade water heater, I think the manufacturer also spent an extra $10 on better internal insulation or something. It uses much less than 1/5th the energy I'd expected, even with the "turn yourself down at night" feature disabled.