Appliance Energy Use Calculator

How to use the appliance energy use calculator

Pick an appliance from the list and it fills in a typical running wattage you can edit, set how many hours a day it runs, and enter your electricity rate; you get the energy and cost both per month and per year. As always, the rate varies — the US residential average is about 17.5¢/kWh as of 2026, but it’s anywhere from roughly 10¢ to over 40¢ by state, so use the figure from your own bill.

The appliances that dominate a bill are the ones that make heat. Electric resistance heating — space heaters, clothes dryers, water heaters, ovens, stovetops — pulls 1,500 to 5,000 watts and dwarfs anything electronic. A 1,500 W space heater running 8 hours costs more in a single day than a 100 W TV does in a week. If you’re hunting for savings, start with the heat.

Then there’s the always-on versus intermittent split. A refrigerator is only 150 watts, but it runs 24/7, so it quietly piles up more than 100 kWh a month. A 3,000 W dryer is enormous but runs an hour at a time. Both belong on the bill, and runtime decides which wins — which is exactly why the “hours per day” input matters as much as the wattage.

The refrigerator is the textbook “small watts, big bill” case. 150 watts sounds trivial, but × 24 hours × 30 days is 108 kWh and about $19 a month, roughly $227 a year — often a household’s single largest plug load. Newer Energy Star models draw less, so editing the watts to your unit’s label sharpens the estimate considerably.

The preset wattages are typical running figures, not your exact unit. The most accurate number is on the appliance’s own label or in its manual, or read with a plug-in meter; switch to Custom and enter it. For cycling appliances like fridges and ACs, the nameplate overstates the average draw, so the preset’s running figure is usually closer to reality than the nameplate would be.

The formula

Monthly energy is the appliance’s power times its daily runtime across a 30-day month; cost is energy times your rate, and the yearly figures are simply twelve months:

monthly kWh = (watts ÷ 1000) × hours per day × 30
monthly cost = monthly kWh × rate
yearly = monthly × 12

Worked example with the default refrigerator — 150 W running 24 hours a day at $0.175/kWh: (150 ÷ 1000) × 24 × 30 = 108 kWh a month, times $0.175 = $18.90 a month, or about $226.80 a year.

Compare that to a 1,500 W space heater at 8 hours a day: 360 kWh and $63 a month. The heater’s power is ten times the fridge’s, but the fridge never switches off — which is exactly why both end up on the same bill.

Frequently asked questions

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