The difference in energy usage between the two is negligible.

I would recommend a 50 gal electric as the minimum size because they don't recover as quickly as a gas heater.

You can always look for the Energy Factor rating on the water heater to know for sure.

BTW: Just noticed your name...

You might consider heatpump water heaters (also called Hybrid) if you live in a warm climate.

GE markets one as does Rheeem. There may be others as well.

They have an energy factor of 2 verses about0.98 for most electric. They take heat from the surrounding air, so they aren't a good match in cold climates.

Here is a link that might be useful: Rheem heat pump water heater

I think the heat pump water heaters add either hot or cool air to the surroundings...if that is an issue...

And, they are noisy. So, it isn't a good choice for a water heater within the living space (as is the case at my house).

Isn't an electric more expensive to run? How much is the rebate? Look at whomismgiving the rebate...They don't care If elec costs more each month than gas..

OP is using propane which can be as expensive as electricity. And they are removing the propane.