Electricity Cost Calculator · Practical guide
How Much Electricity Does a Space Heater Use?
A standard 1,500-watt space heater running 8 hours a day uses 360 kWh per month, costing about $46.80 at the average U.S. rate.
At a glance
The Short Answer
Most portable space heaters draw 1,500 watts on high. Run one for 8 hours a day and it consumes 12 kWh per day, or 360 kWh per month — about $46.80 per month at $0.13 per kWh. That makes space heaters one of the most expensive appliances to run in a home.
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Electricity Cost Breakdown
| Appliance | Monthly kWh | Monthly Cost |
|---|
Monthly Usage by Wattage and Hours
| Setting | 4 Hours/Day | 8 Hours/Day |
|---|---|---|
| 750 W (low) | 90 kWh — $11.70 | 180 kWh — $23.40 |
| 1,000 W (medium) | 120 kWh — $15.60 | 240 kWh — $31.20 |
| 1,500 W (high) | 180 kWh — $23.40 | 360 kWh — $46.80 |
Costs assume 30 days of use at $0.13 per kWh. In states where power costs $0.20 or more per kWh, a 1,500-watt heater on 8 hours daily runs about $72 per month.
Why Space Heaters Use So Much Power
Electric resistance heat converts every watt directly into heat, so there is no efficiency gain like a heat pump delivers. A heater on its high setting pulls about as much power as 15 modern refrigerators running at once, which is why a single heater can add $30 to $50 or more to a winter electric bill.
Cheaper Ways to Stay Warm
- Use the low (750 W) setting once the room is warm — it halves consumption.
- Heat only the occupied room and close the door.
- Use a model with a thermostat and timer so it cycles off automatically.
- Layer up and drop central heat 2°F; even with a heater running in one room, the net bill often falls.
Frequently Asked Questions
Is 1,500 watts a lot for one appliance?
Yes. At 1.5 kW, a space heater draws more continuous power than nearly any other household plug-in device — about the maximum a standard 15-amp, 120-volt outlet can safely supply.
Do oil-filled radiators use less electricity?
They use the same wattage while heating, but the retained oil heat lets them cycle off longer, so real-world consumption is often somewhat lower than a fan heater at the same setting.
Can I run a space heater overnight?
It is cheaper to use a timer so it runs only part of the night. Eight hours of a 1,500W heater costs about $1.56 per night at $0.13 per kWh, and safety guidance recommends models with tip-over and overheat protection for unattended use.
Is a space heater cheaper than central heating?
Only when heating one small room instead of the whole house. Heating an entire home with space heaters usually costs far more than a gas furnace or heat pump.