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What one appliance costs to run
Pick an appliance to load its typical wattage and realistic runtime, or enter your own.
Cost to run
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Choose an appliance or enter a wattage.
Every appliance, ranked by monthly consumption
Costs shown at the US average rate of 18.44¢ per kWh. Runtime is effective duty-cycle time, calibrated against EIA metered consumption data — not hours plugged in.
The hours-plugged-in problem
The arithmetic of appliance cost is trivial: watts times hours, divided by 1,000, gives kilowatt-hours; kilowatt-hours times your rate gives dollars. Nearly every published appliance table gets the arithmetic right and the hours badly wrong.
The Department of Energy's wattage table lists 725 W for a 16 cubic foot frost-free refrigerator. That is peak draw — compressor, condenser fan and defrost heater together. A fridge is plugged in 24 hours a day, so the tempting move is 725 W times 24: 17.4 kWh a day, over 6,300 kWh a year. That would consume most of the 863 kWh an average US home uses in a month, and it overstates a modern fridge tenfold.
The missing concept is duty cycle — the share of time a thermostatically controlled appliance is genuinely drawing power rather than coasting at temperature. A fridge compressor runs about a third of the day, roughly 8 hours, in short cycles when the interior drifts above setpoint. Averaged out, a typical unit behaves like 150 W of continuous draw: about 36.5 kWh a month.
The same error inflates every thermostatic load — air conditioners, water heaters, freezers, dehumidifiers — usually about threefold. It runs the other way too: a WiFi router draws only 5 to 20 W but runs all 8,760 hours of the year, so a 10 W router uses more electricity annually than a 1,500 W toaster used every morning.
Where to get a wattage worth trusting
The nameplate — the data plate giving watts, or amps and volts you multiply (4.5 A at 120 V is 540 W) — is a safety rating used to size circuits, not a description of normal operation. Treat it as a ceiling: a whole-house electric tankless water heater carries a nameplate of 18,000 to 36,000 W, which tells you what breakers it needs and nothing about its bill.
The EnergyGuide label gives estimated annual kilowatt-hours under a standardised federal test procedure. It compares two models of the same type well, but it assumes a test cycle rather than your habits. A new refrigerator's label typically claims 350 to 450 kWh a year, while EIA's 2020 residential survey metered 839 kWh a year for all refrigerators in the average US home — the gap is second fridges in hot garages and fifteen-year-old units.
An inexpensive plug-in meter, left between outlet and appliance for a week, beats both: it measures your appliance, in your house, including its idle draw. The limit is voltage — these work only on 120 V outlets, so the loads that matter most (dryer, range, water heater, central air conditioner, EV charger) need a whole-panel monitor instead.
Ranked by trust: measured beats EnergyGuide, which beats nameplate. Nameplate times hours plugged in belongs nowhere.
Cycling loads, batch loads and always-on loads
Cycling loads run at full power in bursts under thermostat control: refrigerators, freezers, air conditioners, tank water heaters, dehumidifiers, electric heat. Effective hours are clock hours times the duty fraction. A fridge sits near one third. An air conditioner's duty fraction climbs with outdoor temperature, approaching continuous on the hottest afternoons, so central cooling is credited with about 6 hours a day in a hot-climate summer month and 1 to 3 in a mild one.
Batch loads run on demand for a known duration: dryers, dishwashers, ovens, vacuums. Loads per week times minutes per load, divided by 7 and then by 60, gives hours per day. Five dryer loads a week at 45 to 50 minutes averages roughly 0.6 hours a day — idle 97% of the time — and lands near 657 kWh a year, against the 680 kWh EIA measured per household.
Always-on loads — routers, modems, network storage — have no duty cycle at all. Enter 24.
Two patterns fall out. A big nameplate does not mean a big bill: that 18,000 to 36,000 W tankless heater draws power for about half an hour of real hot-water flow a day, landing near 219 kWh a month, modestly below a 4,500 W tank at about 233. And a small nameplate does not mean a small bill: a 500 W dehumidifier running 10 to 16 hours a day through a humid summer reaches about 152 kWh a month.
Seasonal equipment needs one more step: hours for air conditioning, electric heat and pool pumps are in-season hours, so annualise by multiplying by the months the appliance actually runs, not by twelve.
Standby draw, honestly sized
Standby is what a device pulls while switched off or idle: a clock, a remote receiver, a network stack, an instant-on feature. It is worth sizing so you can stop worrying about the wrong half of it.
The small half is very small. A phone charger idles near 0.2 W — about 1.75 kWh across a full year, roughly 32 cents at the US average residential rate of 18.44 cents per kWh. Including the actual charging, a phone accounts for about 0.5 kWh a month; a range clock sits near 3 W, a dishwasher near 1 W. No amount of diligence about these produces a change you can see on a bill.
The other half is worth acting on. A games console in rest mode holds 10 to 15 W around the clock, so for someone playing two hours a day the idle energy roughly matches or exceeds the playing energy. A hot tub's controls sit near 50 W. A router draws about 8 W with no meaningful off state, and heating and cooling equipment carries 15 to 20 W of controls you cannot switch off at all.
The rule: act where a device is continuously energised and drawing double digits. Put consoles and entertainment stacks on a switched strip; leave the chargers alone.
What to do with the number
The value of a per-appliance cost is the rank, not the cost. The question worth answering is not what an appliance costs, but whether it is in the top tier of household loads at all — because attention spent on a phone charger is attention not spent on a water heater.
The top tier is short: central air conditioning at roughly 638 kWh in a cooling month, an electric furnace or heat pump near 532 kWh in a heating month, an electric tank water heater about 233, a space heater about 228, an EV charger and a window air conditioner near 219 each, a pool pump 205, a hot tub 164, a dehumidifier 152. Against the 863 kWh an average US home uses monthly, each is a visible share of the bill. The bottom tier is equally predictable: a router at 5.8 kWh a month, an LED bulb at 0.8, a phone charger at 0.5. Central air conditioning in season uses more than a thousand times what a phone charger does, and only one of those two lists moves a bill.
So rank the loads, then work the top three, using three levers: setpoint, runtime, and the equipment itself. The third is usually the largest — an air-source heat pump draws 3,000 to 5,000 W to warm a house where electric-resistance heat draws 10,000 to 25,000 W for identical comfort.
The full appliance energy table lists all 32 loads with running wattage, effective hours and monthly kilowatt-hours. To convert any figure into money at your own rate, use the kWh cost calculator; if the bill overall is the problem, why is my electric bill so high works through it in order.
Frequently asked questions
Why does this calculator ask for running hours instead of hours plugged in?
Because for anything with a thermostat, the two numbers are wildly different and only one of them predicts a bill. A refrigerator is energised 24 hours a day, but its compressor runs about 8. A tank water heater is connected continuously but fires its element for a fraction of that. Published tables that multiply nameplate wattage by hours plugged in typically overstate cost about threefold, and for a refrigerator by a factor of ten. Entering effective running hours — the hours the appliance is genuinely drawing power — is the difference between an estimate you can act on and a number that is simply wrong.
How do I estimate running hours for something with a thermostat?
Three approaches, in descending order of accuracy. Meter it: a plug-in energy monitor left in place for a week gives total kilowatt-hours, which you divide by wattage to get effective hours. Observe it: note when the compressor or element is audibly running across a few hours and take the fraction. Or borrow a benchmark: a refrigerator runs about a third of the day, a central air conditioner roughly 6 hours a day in a hot-climate summer month and 1 to 3 in a mild one, a basement dehumidifier 10 to 16 hours in humid weather. Benchmarks are a starting point; a meter settles the argument.
Does unplugging chargers and small electronics actually save money?
Barely, and it is worth being blunt about that. A phone charger idling at about 0.2 W costs on the order of 30 cents a year at the US average rate. Unplugging every charger in a house will not produce a change you can detect on a bill. The standby that does matter is concentrated in a few devices holding 10 W or more continuously: games consoles in rest mode, set-top and streaming boxes, mesh network nodes, spa controls. A console idling at 12 W around the clock can use as much energy as it does during play. Act on those; ignore the chargers.
Which electricity rate should I enter?
Use your all-in effective rate, not the supply rate printed in an advertisement. Divide the total amount of a recent bill by the kilowatt-hours it covered; that captures supply, delivery, riders and taxes together, and it is usually meaningfully higher than the headline number. The US average is 18.44 cents per kWh as of May 2026, which is a reasonable placeholder if you do not have a bill in front of you. Two caveats: on a tiered rate, extra consumption is priced at the top tier rather than at your average, and on a time-of-use rate the answer depends entirely on when the appliance runs.