Quick answer: At the US average residential rate of 18.2¢ per kWh (EIA, August 2026), a 1,500 W space heater costs about 27¢ per hour, $2.18 for 8 hours, and about $33 a month if used 4 hours a day.
The Formula
Cost per hour = Watts ÷ 1,000 × Electricity rate per kWh
A 1,500 W heater uses 1.5 kWh every hour on its high setting. Multiply by your rate from your electric bill. Because thermostats cycle the heater on and off, real use is often a bit lower than the maximum.
Space Heater Running Costs
| Heater | Per hour | 8 hours a day for 30 days |
|---|---|---|
| 400 W | $0.07 | $17.47 |
| 750 W | $0.14 | $32.76 |
| 1,000 W | $0.18 | $43.68 |
| 1,500 W | $0.27 | $65.52 |
Costs at 18.2¢ per kWh. Rates vary widely by state, from about 11¢ to over 40¢ per kWh, so use your own rate for an accurate figure.
Skip the math: enter any appliance’s watts, hours and your rate to see the cost per day, month and year. Open the free Electricity Cost Calculator →
Space Heater vs Central Heat
A space heater can save money when you heat one room and turn the central thermostat down for the rest of the house. It costs more than central heat if you try to heat several rooms with several heaters, because electric resistance heat is expensive per unit of heat.
Other Common Appliance Costs
| Appliance | Typical watts | Cost per hour |
|---|---|---|
| LED bulb | 10 | $0.002 |
| Ceiling fan | 75 | $0.014 |
| TV | 120 | $0.022 |
| Window AC | 1,000 | $0.182 |
| Hair dryer | 1,800 | $0.328 |
| Electric oven | 2,400 | $0.437 |
Ways to Lower the Cost
- Use the heater’s thermostat or a lower setting.
- Close the door to keep heat in the room.
- Seal drafts around windows and doors.
- Add attic insulation; see our insulation calculator.
- Never leave a space heater running unattended or near curtains and bedding.
Worked Example With Your Own Rate
- Find the wattage on the heater’s label: 1,500 W.
- Convert to kilowatts: 1,500 ÷ 1,000 = 1.5 kW.
- Multiply by hours used: 1.5 × 6 hours = 9 kWh per day.
- Multiply by your rate: 9 × $0.25 = $2.25 per day.
- Multiply by days: $2.25 × 30 = $67.50 per month.
Do Low and High Settings Matter?
Most heaters run at about 750 W on low and 1,500 W on high. Once the room reaches the thermostat setting, the heater cycles on and off, so the average power can be well below the maximum. A smart plug with energy monitoring shows exactly how many kWh your heater uses.
Types of Space Heaters
- Ceramic fan heaters: heat a room quickly; good for short use.
- Oil-filled radiators: slow, quiet and even heat for longer periods.
- Infrared heaters: warm people and objects directly; good for drafty spaces.
- All 1,500 W electric heaters turn electricity into heat at essentially the same efficiency.
Space Heater Safety
- Plug heaters directly into a wall outlet, not an extension cord or power strip.
- Keep at least 3 ft of clearance from furniture, curtains and bedding.
- Choose models with tip-over and overheat shut-off.
- Turn heaters off when you leave the room or go to sleep.
Sources
Frequently Asked Questions
How much does it cost to run a 1500 watt heater for 24 hours?
At 18.2¢ per kWh, about $6.55 if it ran continuously on high.
Are space heaters expensive to run?
They cost about 27¢ an hour at average US rates, which is affordable for one room but expensive for heating a whole home.
Do oil-filled heaters use less electricity?
No. A 1,500 W oil-filled heater uses the same power as any 1,500 W heater; it just releases heat more gradually.
How many kWh does a space heater use?
A 1,500 W heater uses 1.5 kWh per hour on high.
Is it cheaper to use a space heater or turn up the heat?
Heating one occupied room with a space heater while lowering the thermostat can be cheaper; heating many rooms with space heaters usually is not.
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