A common input is

**34,000 BTUs**on a 40-gallon tank and**36,000 BTUs**on a 50-gallon tank. The higher the BTU input and efficiency, the faster the recovery. Electric water heaters typically have one 5,500-watt or two 4,500-watt elements.Accordingly, how many BTUs does it take to boil one pound of water?

lbs of water x temperature rise = BTUs required for one hour (1 lb of water x 1 degree Fahrenheit) = 1 BTU for 1 hour.

Water equals 8.3 lbs per gallon. To boil one gallon of water starting 70°F in 1 hour you will need 8.3 x (

Water equals 8.3 lbs per gallon. To boil one gallon of water starting 70°F in 1 hour you will need 8.3 x (

**212**-70) =**1,178.6 BTUs**.How many kilowatts does it take to heat a gallon of water?

Energy required to heat one gallon of water, and one tank of water. Heating a gallon of water by 1°F with no losses thus takes 8.33 lbs x 1 Btu/lb = 8.33 Btu's. Heating a gallon of water by 1°F with no losses thus takes 8.33 ÷ 100,000 = 0.00008.33 therms.

**One kWh**is 3413 Btu's, so one Btu is**1/3413**=**0.000293 kWh**.How many BTU's does it take to boil a gallon of water?

A BTU (British Thermal Unit) describes the amount of energy to raise 1 lb of water 1 degree Fahrenheit in one hour. Water equals 8.3 lbs per gallon. To boil one gallon of water starting 70°F in 1 hour you will need 8.3 x (

**212-70**) =**1,178.6 BTUs**.