Price any appliance: turn its watts into kWh, then into dollars

Multiply an appliance's watts by the hours it runs in a day and divide by 1,000: that is its kWh a day, and kWh times your rate is the cost. EIA's page on measuring electricity works the first step for a 40-watt bulb used for five hours: 200 watthours, or 0.2 kWh. At 18.31 cents per kWh, the US residential average for July 2026 in EIA's Electric Power Monthly, Table 5.6.A (preliminary), those five hours cost 3.7 cents, and every kWh a day adds $66.83 a year. One condition changes the method: a fridge or dehumidifier cycles on and off, so meter it for 24 hours instead of multiplying its label watts. The arithmetic is free for renters and owners; a plug-in meter is an optional small buy.

Watts times hours, divided by 1,000, gives the day's kWh

Find the watts on the device's label or in its manual. The hours are yours: how long it runs on a typical day. Watts × hours ÷ 1,000 is kWh a day; kWh a day × your rate in cents is cents a day; cents a day × 365 is a year. EIA's measuring page defines the units behind it: one kilowatt is 1,000 watts, and one kWh is one kilowatt for one hour.

Example, with published figures. DOE's 2022 Energy Saver guide reprints the FTC's Lighting Facts label for a 450-lumen bulb that uses 9 watts, with an estimated yearly energy cost of $1.08 based on 3 hours a day at 11 cents per kWh. The method gives the same answer: 9 watts × 3 hours ÷ 1,000 = 0.027 kWh a day, × 365 = 9.855 kWh a year, × 11 cents = 108 cents, or $1.08. Reprice it at the July 2026 US residential average of 18.31 cents in EIA's Table 5.6.A: 9.855 × 18.31 cents = 180 cents, or $1.80 a year. A printed cost ages with its rate.

Meter a fridge or dehumidifier for 24 hours instead

A compressor does not run all day. ENERGY STAR's dehumidifier page says a dehumidifier with a humidistat cycles on and off automatically to hold the humidity you set, and Berkeley Lab's meter page mentions short periods when a refrigerator's compressor is not working. Label watts × 24 hours counts those off periods as running time. Plug the appliance into a plug-in meter for 24 hours instead and read the kWh it shows. That reading is the day's kWh, so skip the hours step and multiply it by your rate. The same 24-hour reading is where the decision to unplug the second fridge starts.

Berkeley Lab's standby FAQ says meters sell online for less than $50 and some libraries loan them, and that most are reasonably accurate, with errors that grow relatively larger below about 1 watt, the range that matters when you meter the always-on devices. Its list of meters adds a limit: most consumer-grade meters can't safely measure more than about 1,300 watts. Keep a portable space heater, an induction stovetop or another large heat-making device off the meter. Price it from its label watts, as in heating one room with a space heater.

A refrigerator with an EnergyGuide label offers a second route. DOE's 2022 guide shows the label's estimated yearly electricity use in kWh and calls its numbers averages: actual costs differ somewhat with how you use the appliance. Multiply that yearly kWh by your own rate rather than reading the label's dollars. The guide's sample label bases its cost on a national average of 12 cents per kWh, so check which rate yours names.

Your rate is your bill's dollars divided by its kWh

Check your latest bill for the total dollars and the kWh billed. Divide the dollars by the kWh and multiply by 100: that is your all-in rate in cents per kWh, with any fixed charge spread over each kWh. If that rate rises from one July to the next while your kWh hold steady, the price went up, not your use. Without a bill at hand, take your state's residential row in EIA's Electric Power Monthly, Table 5.6.A and keep its month with it. The July 2026 figures are preliminary, and EIA lists its next release for October 23, 2026.

What 1 kWh a day costs at July 2026 residential prices from EIA's Table 5.6.A, for a 30-day month and for a year:

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Multiply any row by kWh a day. The 9-watt bulb's 0.027 kWh a day comes to $1.80 a year on the US row and $4.73 on the Hawaii row.