Tool · Investor Sam Green

Appliance Energy Cost Calculator

June 30, 2026 • By the Investor Sam Editorial Team • Reviewed by Berly Sam Varghese, Editor
Every appliance quietly adds to your electric bill, and the only inputs you need to size that cost are its wattage, how many hours a day it runs, and your electricity rate. This calculator converts those into kilowatt-hours and dollars so you can see what a space heater, gaming PC, refrigerator, or window AC actually costs to run for a year — and decide what is worth unplugging or upgrading.

Example: Appliance power draw: 1500 W · Hours used per day: 4 hrs · Electricity rate: 0.17 $/kWh

Annual running cost$372
Electricity used per year2,190
Average monthly cost$31

Worked example

A 1,500-watt space heater running 4 hours a day draws 1.5 kW, or 6 kWh daily and about 2,190 kWh a year. At $0.17 per kWh that costs roughly $372 a year, or about $31 a month. Seeing that number is often what convinces people to seal drafts and add a sweater rather than lean on a resistance heater all winter.

Frequently asked questions

Where do I find an appliance's wattage?

Check the nameplate label on the appliance, the manual, or the manufacturer's specs; it is usually listed in watts or amps. If only amps are given, multiply amps by voltage (typically 120 in the U.S.) to get watts. A plug-in energy meter gives the most accurate real-world reading.

Does this account for appliances that cycle on and off?

For appliances like refrigerators that cycle, enter the equivalent hours per day they actually run, not the 24 hours they are plugged in — often 8 to 12 hours of compressor time. For always-on constant-draw devices, use the full hours. Matching run hours to reality keeps the estimate accurate.

Which appliances cost the most to run?

High-wattage devices used many hours dominate: electric water heaters, HVAC, dryers, space heaters, and pool pumps. Low-wattage electronics cost little individually. Running each big one through this tool shows where your bill really goes and where an upgrade or behavior change pays off most.

How can I lower an appliance's running cost?

Use it fewer hours, replace it with an ENERGY STAR model that draws less power, or run it during off-peak hours if you are on a time-of-use rate. The annual figure here makes it easy to compare the savings of a more efficient replacement against its purchase price.

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Sources

Berly Sam Varghese · Editor, Investor Sam

Berly Sam Varghese is an engineer who treats money the way he treats any hard problem — something to be engineered, not gambled on. He funded years of education and built real financial stability the patient way, by living below his means and investing rather than borrowing. He writes for the person trying to make a greener choice that also makes financial sense. He reviews and approves every article on Investor Sam and checks the figures against primary sources before anything is published. More about our standards.