Space Heater Electricity Cost Calculator
Electric space heaters are simple, cheap to buy, and surprisingly expensive to run. Nearly all of them draw a full 1,500 watts on high — and unlike a refrigerator, a space heater runs at essentially full power the entire time it's on, with no duty cycle to soften the bill. That combination makes them one of the costliest appliances per hour in the house. This calculator shows exactly what yours costs by the hour, day, and month so you can decide when it's worth running.
watts × hours × duty ÷ 1000
at your state rate
this appliance
Results update live as you type. For planning and field-check estimates — always verify against applicable standards and equipment ratings.
How we calculate this →The real cost of supplemental electric heat
A 1,500 W space heater running 4 hours a day uses about 3.6 kWh — roughly 61 cents a day at the U.S. average rate, or around $18 a month. Run it in two rooms for 8 hours and you're over $70 a month just in space heater costs. The duty cycle matters too: thermostatic heaters cycle off once temperature is reached, so a 60% duty cycle is realistic in mild conditions but 100% on the coldest nights.
For comparison, a heat pump delivers 2–4 units of heat per unit of electricity, making it 200–400% more efficient than a resistive space heater. If you're using space heaters as primary heat for a significant portion of your home, upgrading to a mini-split heat pump almost always pays back quickly.
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