Appliance Cost to Run Calculator

A 1,500 W heater used 8 hours a day with normal thermostat cycling uses about 216 kWh a month, which is roughly $37.37 at the 2025 US average of 17.3 cents per kWh. In the cheapest states it is closer to $25.51. In Hawaii it is about $87.67. If the heater runs flat out with no cycling, add two thirds to those figures.

Take the total amount of your last electric bill, including delivery charges, riders and taxes, and divide it by the kWh used that month. That all-in figure is the rate that applies to the next kWh you use. The supply rate printed on the bill is usually only half the story because delivery is billed separately. If you are on a time-of-use plan, use the rate for the hours the appliance actually runs.

A kilowatt-hour is the energy used by a 1,000 W load running for one hour. It is what the utility bills for. A 100 W bulb for 10 hours, a 500 W pump for 2 hours and a 2,000 W oven for 30 minutes each use one kWh. Watts measure how fast energy is being used, and kWh measure how much was used in total.

A little. Chargers, TVs, game consoles, microwaves with a clock and cable boxes draw anywhere from under 1 W to 30 W when idle. One device at 5 W around the clock is about 44 kWh a year, or $5 to $15 depending on your state. A cable box or console in instant-on mode can be three to five times that. Enter 24 hours and the standby watts in the calculator to see any device's idle cost.

In most homes the order runs heating and cooling first, then the electric water heater, then the pool pump or hot tub if there is one, the clothes dryer, the refrigerator and freezer, and an EV charger if you have one. Small appliances like microwaves and coffee makers draw a lot of watts but for so few minutes that they stay at the bottom of the list. Always-on loads like a home server or an old second fridge climb the list on hours alone.

The math is exact, but the inputs are estimates. The watts are typical values for current models, the duty cycles are reasonable averages, and the rates are annual state averages. Your appliance, your weather and your rate plan all move the real figure. For the closest answer, measure the appliance with a plug-in meter for a few days, enter the measured watts with a 100% duty cycle, and type in the all-in rate from your bill.

Three usual reasons. First, the bill includes fixed monthly charges that have nothing to do with usage. Second, your rate may be tiered or time-of-use, so the kWh you add at peak times cost more than the state average. Third, the appliance may be running more hours or at a higher duty cycle than the default, which is common for heaters in cold rooms, air conditioners in hot ones and old refrigerators. Enter your own numbers in each box to close the gap.

If your central heat is a heat pump, it is cheaper per unit of heat by a factor of two to three, so the space heater only wins when it lets you heat one room and leave the rest of the house cold. If your central heat is gas, it usually beats a space heater at the whole-house level, but heating one occupied room with the furnace turned down can still save money. If your central heat is electric resistance, the cost per unit of heat is the same and the only saving comes from heating fewer rooms.

A typical current refrigerator draws about 150 W while the compressor runs and runs about 35% of the time, so it uses about 1.26 kWh a day or 460 kWh a year. At the 2025 US average of 17.3 cents per kWh that is about $79.56 a year. For your exact model, take the kWh per year from the yellow EnergyGuide label and multiply it by your rate.

Look for the rating plate on the back, bottom or inside the door, or in the manual. If it lists only amps and volts, multiply them: 12.5 A at 120 V is 1,500 W. The plate shows the maximum draw, so most appliances use less on average, which is what the duty cycle box corrects for. A plug-in watt meter measures the real draw and logs the kWh over a few days.