Engine block heater vs. garage heater: running cost
An engine block heater is cheaper to run: about $70 a year versus $188 for a garage heater at typical use and 17.99¢/kWh, a $117 difference.
| Engine block heater | Garage heater | |
|---|---|---|
| Typical watts | 750 W | 5,000 W |
| Watt range | 150–1,500 W | 4,000–10,000 W |
| Typical use | 8 hours a day, 5 days a week for 3 months a year | 4 hours a day, 4 days a week for 5 months a year |
| Energy per year | 391 kWh | 1,044 kWh |
| Cost per hour | 13¢ | 54¢ |
| Cost per day | 77¢ | $1.23 |
| Cost per month | $23.47 | $37.55 |
| Cost per year | $70 | $188 |
| Per year in Hawaii (43.51¢) | $170 | $454 |
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What drives the difference
- Engine block heater: Block heaters run at full power with no thermostat. Most of the warming benefit happens in the first 2-3 hours, so overnight use wastes most of the energy.
- Garage heater: Hardwired 240 V garage and shop heaters are typically 4,000-10,000 W. Uninsulated garages make them run near continuously, so insulation drives the cost more than the heater does.
Ways to cut either cost
Runs the heater only 2-3 hours before departure.
See options on AmazonKeeps the heater off on nights when it is not cold enough to need it.
See options on AmazonCuts heat loss through the door, often reducing heater runtime by 25-40%.
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, an engine block heater or a garage heater?
At typical use and the U.S. average rate (17.99¢/kWh), a garage heater costs about $188 a year versus $70 for an engine block heater. That's $117 more, or 2.7× as much.
How many watts do engine block heater and garage heater use?
An engine block heater typically draws 750 W (range 150–1,500 W). A garage heater draws 5,000 W (range 4,000–10,000 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.