How to work out what an appliance costs to run
Your utility sells electricity by the kilowatt-hour (kWh): 1,000 watts running for one hour. Turn any appliance into kWh and you can price it. This is the method the Department of Energy publishes, and the math the calculator runs. Here it is with the values the calculator opens with: a 900-watt window air conditioner, 8 hours a day, every day, for the four warm months, at the August 2026 U.S. average of 18.16 cents per kWh.
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1
Find the watts
Read the nameplate. If it only gives amps, multiply by the volts. A window unit rated 7.5 amps at 120 volts draws 900 watts.
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Watts × hours ÷ 1,000 = kWh per day
900 × 8 ÷ 1,000 = 7.2 kWh on each day it runs. One hour is 0.9 kWh, so each hour costs 0.9 × $0.1816 = 16.3 cents, and a full day $1.31.
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3
Scale to a month
A month averages 30.4 days (365 ÷ 12). At 7 days a week that is 7.2 × 30.4 = 219 kWh, or $39.77 a month while it's in use.
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4
Multiply by the months you use it
Four months comes to 876 kWh and $159 a year. If you add standby watts, the calculator counts them for every hour the appliance is plugged in but not running, all year.
Fewer days a week scale the month down in proportion: a dishwasher run 5 days a week counts 5/7 of each month. Months per year handle seasonal loads like air conditioners, space heaters, dehumidifiers and pool pumps.
Running hours are not "on" hours
Anything with a thermostat or compressor cycles. A refrigerator is plugged in 24 hours a day, but the DOE says to divide that by three to estimate the time it actually draws its full wattage. The same goes for freezers, air conditioners, dehumidifiers, water heaters and space heaters set to a temperature: they run hard, shut off, then start again. That's why the calculator asks for hours running.
The opposite trap is the nameplate itself. The DOE notes that the label shows the maximum power drawn. A fan on low, a TV at half brightness or a laptop at idle use less. When the number matters, measure it: a plug-in usage monitor for a 120-volt device shows the real watts, and left in place for a week it gives you the real kWh.
Typical watts and cost per hour
These are the defaults in the calculator, priced at 18.16 cents per kWh. The DOE column is the range of nameplate wattages the Department of Energy listed for that kind of appliance; dashes mean it didn't list one, and our figure is a typical running value. Yours may differ, so use the label on your model when you can.
| Appliance | Watts | DOE range | Per hour | Per year* |
|---|---|---|---|---|
| Window AC unit | 900 | – | 16.3¢ | $159 |
| Central air conditioner (3-ton) | 3,000 | – | 54.5¢ | $398 |
| Space heater | 1,500 | 750–1,500 | 27.2¢ | $133 |
| Ceiling fan | 50 | 65–175 | 0.91¢ | $13 |
| Window or box fan | 100 | 55–250 | 1.82¢ | $18 |
| Dehumidifier | 500 | 785 | 9.08¢ | $199 |
| Electric blanket | 100 | 60–100 | 1.82¢ | $8.84 |
| Refrigerator | 150 | 725 | 2.72¢ | $80 |
| Chest freezer | 100 | – | 1.82¢ | $53 |
| Electric oven and range | 2,400 | – | 43.6¢ | $114 |
| Microwave | 1,100 | 750–1,100 | 20.0¢ | $18 |
| Dishwasher | 1,500 | 1,200–2,400 | 27.2¢ | $71 |
| Coffee maker | 1,000 | 900–1,200 | 18.2¢ | $17 |
| Electric kettle | 1,500 | 1,500 | 27.2¢ | $25 |
| Toaster | 1,100 | 800–1,400 | 20.0¢ | $7.29 |
| Toaster oven | 1,225 | 1,225 | 22.2¢ | $14 |
| Air fryer | 1,500 | – | 27.2¢ | $36 |
| Electric clothes dryer | 3,000 | 1,800–5,000 | 54.5¢ | $85 |
| Clothes washer | 500 | 350–500 | 9.08¢ | $14 |
| Clothes iron | 1,200 | 1,000–1,800 | 21.8¢ | $5.68 |
| Vacuum cleaner | 1,200 | 1,000–1,440 | 21.8¢ | $11 |
| Hair dryer | 1,500 | 1,200–1,875 | 27.2¢ | $25 |
| TV (55-inch LED) | 100 | – | 1.82¢ | $33 |
| Game console | 150 | – | 2.72¢ | $20 |
| Desktop PC and monitor | 200 | 270 | 3.63¢ | $53 |
| Laptop | 50 | 50 | 0.91¢ | $20 |
| Wi-Fi router and modem | 15 | – | 0.27¢ | $24 |
| LED bulb (60 W equivalent) | 9 | – | 0.16¢ | $2.98 |
| Incandescent bulb, 60 W | 60 | – | 1.09¢ | $20 |
| Electric water heater (40–50 gal) | 4,500 | 4,500–5,500 | 81.7¢ | $895 |
| EV charging (Level 2) | 7,200 | – | $1.31 | $716 |
| Pool pump | 1,500 | – | 27.2¢ | $398 |
| Well pump | 750 | 250–1,100 | 13.6¢ | $75 |
*With the typical hours, days and months shown in the calculator for each one. The DOE's 725 W for a refrigerator is the nameplate of an older 16 cubic foot frost-free model, and its 270 W for a computer is a desktop tower plus monitor; today's models draw less.
Using the EnergyGuide label instead
Refrigerators, freezers, dishwashers, clothes washers, water heaters and TVs sold in the U.S. carry the yellow EnergyGuide label required by the Federal Trade Commission. Its estimated yearly electricity use in kWh comes from a standard test, so it already accounts for a fridge cycling on and off. That makes it a better starting point than watts for those appliances. Switch the calculator to "I have the EnergyGuide label," type the kWh, and it prices it at your rate. Ignore the dollar figure on the label: it is computed at a fixed national reference rate, and today's rates are higher in most states.
The label tests a new unit under set conditions. An older fridge with worn door seals, a freezer in a hot garage, or a dishwasher run on the heated-dry setting will use more.
Where the money really goes
Watts tell you most of the story. Anything that makes heat or removes it draws 1,000 to 5,000 watts, so a few hours a day add up to real money. Electronics draw tens of watts. A 55-inch LED TV watched 5 hours a day costs about $33 a year at the national average; a window AC on the default settings costs that in under four weeks.
- Heat makers: a space heater, electric kettle, hair dryer or toaster oven runs at 1,100 to 1,500 watts, about 20 to 27 cents an hour. Short bursts are cheap; hours a day are not. Our space heater cost calculator goes deeper on that one.
- Always-on loads: a router, modem, aquarium heater or old second fridge never stops. Small watts times 8,760 hours a year matter. A 15-watt router and modem cost about $24 a year.
- Lighting: one 60-watt incandescent bulb on 5 hours a day uses 110 kWh a year, about $20. The 9-watt LED that replaces it uses 16 kWh, about $3. The LED savings calculator runs that for a whole house.
- Big 240-volt loads: a dryer, range, water heater or EV charger can each be the largest line on a bill. These need a licensed electrician for any new circuit or rewiring, and a plug-in monitor won't fit them. A panel energy monitor or your utility's smart-meter data shows their use.
To see every appliance at once and how they add up to a monthly bill, use the electric bill calculator. Our guide on how to lower your electric bill ranks the fixes by payback.
Standby power
Many devices keep drawing a trickle of power when they look off: TVs waiting for the remote, consoles in rest mode, microwaves with a clock, chargers left in the wall. The DOE calls these phantom loads and says most add a few watt-hours. One device rarely matters, but a dozen do. If a usage monitor shows, say, 5 watts with the device off, type that in the standby box and the calculator adds it for every hour it isn't running. Five watts around the clock is 44 kWh a year, about $8. A switched power strip stops it.
Tips for cutting the cost
- Go after hours on the big ones first. One hour less a day on the default window AC saves 0.9 kWh a day, about $20 over a four-month summer.
- Check your real rate. If your plan has time-of-use pricing, running the dishwasher, dryer or EV charger at night can cost far less than the average rate shown here.
- Price the replacement before it breaks. Compare the label kWh of a new ENERGY STAR model with your old one measured on a monitor, then price both here. The yearly gap times the years you'll keep it is what efficiency is worth to you.
- Keep coils and filters clean. Dusty fridge coils, a clogged AC filter and a full dryer lint screen all make the motor run longer for the same work.
- Mind the cords. Heaters and other high-wattage plug-ins should go straight into a wall outlet, not an extension cord or power strip.
Common questions
How do I calculate how much an appliance costs to run?
Multiply the watts by the hours it runs and divide by 1,000 to get kWh, then multiply by your price per kWh. A 900-watt window air conditioner running 8 hours uses 7.2 kWh, which costs about $1.31 a day at the August 2026 U.S. average of 18.16 cents per kWh.
How much does it cost to run an appliance for an hour?
Divide the watts by 1,000 and multiply by your rate. At 18.16 cents per kWh, a 1,500-watt heater or kettle costs about 27 cents an hour, a 100-watt TV about 2 cents and a 9-watt LED bulb about a sixth of a cent.
How do I find out how many watts an appliance uses?
Look for the nameplate on the back or bottom, or in the manual. If it lists only amps, multiply amps by volts: 120 volts for a standard outlet and 240 volts for dryers, ranges and water heaters. A plug-in usage monitor shows the real draw of anything on a 120-volt outlet.
How much does it cost to run a refrigerator?
A typical refrigerator draws about 150 watts while the compressor runs, which is about a third of the day. That is 1.2 kWh a day or about 438 kWh a year, roughly $80 a year at 18.16 cents per kWh. The yellow EnergyGuide label on a newer model gives its rated kWh per year.
Do appliances use electricity when turned off?
Many do. TVs, game consoles, chargers and anything with a clock or remote draw a small standby load. The Department of Energy says these phantom loads usually add a few watt-hours, and you can stop them by unplugging the device or switching off a power strip.
Which appliances use the most electricity?
Anything that heats or cools: central and window air conditioners, electric heat, an electric water heater, the clothes dryer, an electric range, a pool pump and EV charging. Electronics and LED lights draw little power, so they rarely move the bill much.
Sources and assumptions
- State rates: U.S. Energy Information Administration, Electric Power Monthly, Table 5.6.A, average residential price for August 2026 (released October 23, 2026; preliminary). The same rates as our electric bill calculator.
- Method, refrigerator duty cycle (plugged-in time ÷ 3), nameplate and amps × volts, and standby loads: U.S. Department of Energy, Estimating Appliance and Home Electronic Energy Use (archived; the live page has been removed).
- Nameplate wattage ranges in the table: the DOE's typical wattages of various appliances list (archived 2014 version). Several entries on it, like tube TVs, are dated, so the calculator uses typical running watts for current models, the same values as our electric bill calculator. The air fryer figure (1,500 W) is a HomeOutlay estimate from the 1,400 to 1,800 W printed on common 4 to 6 quart models.
- EnergyGuide labels: Federal Trade Commission, How To Use the EnergyGuide Label To Shop for Home Appliances. Model comparisons: ENERGY STAR product finder.
- HomeOutlay assumptions: a month is 365 ÷ 12 = 30.4 days; days per week scale each month (5 days a week = 5/7 of it); standby watts count for every hour of the year the appliance isn't running. Fixed monthly fees, taxes, tiered and time-of-use pricing are not included unless you fold them into your own rate.