This calculator shows the approximate costs of heating water for a typical family. Gallons-per-day, temperature rise, cost-per-unit, and energy factor values are all adjustable. This calculator is for comparison purposes only. Actual performance may vary. Default energy prices last updated: 12/07/2021.
kWh (Kilowatt hour) - A unit of electricity.
therm - A measure of natural gas heat energy equal to 100,000 BTUs.
LP (liquefied petroleum) - Liquefied petroleum gas. Also referred to as propane or butane gas.
Energy Factor - A measure of efficiency. An energy factor of 0.50 is 50% efficient.
Temperature Rise - The temperature difference between the cold and hot water. Typical incoming water is 50°F and is generally heated to 120°F, so the typical temperature rise is 70°F.
Gal/Day - Gallons per day of hot water used. A typical family uses 50 gallons per day.
Gal - Gallon.