Actually, I'm going to disagree - conventional gas water heaters don't use any electricity at all, not even internally generated by a junction device. Strictly thermal-mechanical (fluid in the tube). Just replaced mine - yep; still make 'em just like they used to. Except I got one with dual magnesium anodes and a swirl fill tube.

I chose this - conventional type - over a condensing unit specifically because it's immune to electrical outages (plus it will last longer and needs no repairs or maintenance).

If it has a pilot light and it doesn't have a blower, there's no electricity involved.

There are gas water heaters that need some electrical power, of course - condensing units (forced exhaust, high efficiency - whatever name they go by).

Regards,

Tom