Unless you have a solar tank, you’d still be using 10-20 kW, just deriving the energy from burning natural gas (yay for dirt-cheap global warming from fossil farts!!!) rather than electricity. kW is a measurement of energy consumption rate (kJ/s), not necessarily in the form of electricity.
1kW = ~3400 BTU/hr. It would be simpler of Americans actually got the Metric system and didn’t stick to their antediluvian system of engineering units, but so it goes.
