Well a electric hot water heater is either 2500 watts or 4500 watts, There are some that are 5000 to 5500 watts. Most in my area are 4500 watts. 1000 watts equals about 3500 btu, so a water heater is about 15,750 btu if it is the 4500 watt type. That said there is most of the time two heat...