per kilowatt-hour
Cost per energyexact by definition
Cost per kilowatt-hour is the universal retail electricity price, and increasingly the basis for comparing any energy source. A kilowatt-hour is exactly 3.6 megajoules, so the conversion to cost per joule is exact by definition. Typical North American residential electricity runs from about 8 to 30 cents per kilowatt-hour depending on the jurisdiction.
| 1 $/kWh | 1 $/kWh |
About the per kilowatt-hour
The kilowatt-hour is energy, not power: one kilowatt sustained for one hour, which is exactly 3.6 MJ. That distinction is what makes a utility bill legible. A 1500 W space heater running four hours a day uses 6 kWh a day and 180 kWh a month, so at 15 cents that is $27 a month from one appliance. The general form is simply \(\ ext{cost} = P \ imes t \ imes \ ext{rate}\), and almost every energy saving calculation reduces to it.
Comparing fuels means putting them on a common energy basis, which is exactly what this converter is for. Natural gas sold at $8 per gigajoule is about 2.9 cents per kilowatt-hour of fuel energy, roughly a fifth the price of typical grid electricity per unit of energy. That gap is why gas heating persists, and also why heat pumps change the arithmetic: a unit with a coefficient of performance of 3 delivers three kilowatt-hours of heat per kilowatt-hour of electricity bought, cutting the effective cost per delivered kilowatt-hour to a third. Fuel comparisons also have to account for appliance efficiency, since a gas furnace at 85 percent burns more fuel energy than it delivers as heat while resistance electric heating is 100 percent efficient at the point of use.