Small space heater vs. under-desk heater: running cost
An under-desk heater is cheaper to run: about $23 a year versus $46 for a small space heater at typical use and 17.99¢/kWh, a $24 difference.
| Small space heater | Under-desk heater | |
|---|---|---|
| Typical watts | 400 W | 170 W |
| Watt range | 200–800 W | 30–300 W |
| Typical use | 6 hours a day for 5 months a year | 8 hours a day, 5 days a week for 5 months a year |
| Energy per year | 257 kWh | 126 kWh |
| Cost per hour | 5.0¢ | 2.6¢ |
| Cost per day | 30¢ | 15¢ |
| Cost per month | $9.25 | $4.52 |
| Cost per year | $46 | $23 |
| Per year in Hawaii (43.51¢) | $112 | $55 |
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What drives the difference
- Small space heater: Personal and plug-in outlet heaters draw roughly 200-800 W. They can only warm the person sitting nearby, not a room.
- Under-desk heater: Radiant panel and foot warmer heaters draw 30-300 W and warm only your legs and feet, which is why they cost a fraction of a 1,500 W space heater.
Ways to cut either cost
Covers more of your body at a similar 50-100 W.
See options on AmazonEnsures the heater only runs during working hours.
See options on AmazonRadiant panels warm your legs at 150-200 W with no fan noise.
See options on AmazonWe may earn a commission from qualifying purchases. It never changes the numbers we show. Disclosure.
Frequently asked questions
Which costs more to run, a small space heater or an under-desk heater?
At typical use and the U.S. average rate (17.99¢/kWh), a small space heater costs about $46 a year versus $23 for an under-desk heater. That's $24 more, or 2.0× as much.
How many watts do small space heater and under-desk heater use?
A small space heater typically draws 400 W (range 200–800 W). An under-desk heater draws 170 W (range 30–300 W). Watts alone don't decide cost. Hours of use, cycling and standby matter just as much.
Rates: EIA, 12 months ending 2026-07. Methodology.