My power coop has a special rate 5.2 cents per kWh when you go with the off peak storage water heater deal. We have been averaging $13.50 per month with 80 gal unit and 2 people in the household. It's just a basic unit - have not had time to insulate it yet but will get that done soon (that's what I decided 3 years ago when we bought the house). The heater is 16 years old now, and we have super hard high iron well water with a softener. No problems yet, but I have a spare unit sitting in the barn (got a very lightly used unit free). I also have natural gas connection so have been thinking about switching to NG water heat, as well as played with an idea about DIY solar water heater, but with only $160 annual cost with a electric water right now does not seem to make sense to change anything.