How much does it cost to run an engine block heater?
An engine block heater drawing 750 watts, used 4 hours a day, uses about 3.00 kWh per day and costs about $0.58 per day, $17.73 per month, and $212.54 per year at the US average residential rate of 19.4¢/kWh. Enter your own wattage, hours, and state below for an exact figure.
Estimates only — based on typical wattages and average state rates, not your actual bill.
What drives the cost
A block heater draws 400-1,500 watts and is commonly left plugged in all night, which is far longer than necessary. Most engines reach useful warmth within about three to four hours, so a timer typically cuts the cost by half or more with no loss of benefit.
Cost at different daily usage
Same engine block heater at 750 watts, run for different amounts of time, at 19.4¢/kWh.
| Usage | kWh/day | Per day | Per month | Per year |
|---|---|---|---|---|
| 2 h/day | 1.50 kWh | $0.29 | $8.86 | $106.27 |
| 4 h/day | 3.00 kWh | $0.58 | $17.73 | $212.54 |
| 6 h/day | 4.50 kWh | $0.87 | $26.59 | $318.81 |
| 8 h/day | 6.00 kWh | $1.16 | $35.45 | $425.08 |
Cost by model power draw
Not all models are equal. At 4 h/day, here is what the range costs.
| Model | Power | kWh/day | Per day | Per month |
|---|---|---|---|---|
| Low-draw model | 400 W | 1.60 kWh | $0.31 | $9.45 |
| Typical | 750 W | 3.00 kWh | $0.58 | $17.73 |
| High-draw model | 1,500 W | 6.00 kWh | $1.16 | $35.45 |
Cost by state
An engine block heater at 750 W for 4 h/day, priced at each state's average residential rate.
| State | Rate | Per day | Per month | Per year |
|---|---|---|---|---|
| Alabama | 16.8¢ | $0.50 | $15.31 | $183.63 |
| Alaska | 28.2¢ | $0.85 | $25.78 | $309.12 |
| Arizona | 15.2¢ | $0.46 | $13.91 | $166.77 |
| Arkansas | 14.4¢ | $0.43 | $13.11 | $157.24 |
| California | 33.2¢ | $1.00 | $30.36 | $364.09 |
| Colorado | 16.2¢ | $0.48 | $14.76 | $176.95 |
| Connecticut | 27.4¢ | $0.82 | $24.99 | $299.70 |
| Delaware | 19.4¢ | $0.58 | $17.70 | $212.21 |
| District of Columbia | 25.4¢ | $0.76 | $23.20 | $278.13 |
| Florida | 15.2¢ | $0.46 | $13.85 | $166.11 |
| Georgia | 15.8¢ | $0.48 | $14.47 | $173.45 |
| Hawaii | 52.0¢ | $1.56 | $47.49 | $569.40 |
| Idaho | 12.3¢ | $0.37 | $11.28 | $135.23 |
| Illinois | 23.9¢ | $0.72 | $21.78 | $261.16 |
| Indiana | 18.1¢ | $0.54 | $16.57 | $198.74 |
| Iowa | 14.1¢ | $0.42 | $12.91 | $154.83 |
| Kansas | 15.1¢ | $0.45 | $13.82 | $165.67 |
| Kentucky | 15.0¢ | $0.45 | $13.68 | $164.03 |
| Louisiana | 14.2¢ | $0.42 | $12.92 | $154.94 |
| Maine | 28.6¢ | $0.86 | $26.14 | $313.50 |
| Maryland | 21.8¢ | $0.65 | $19.88 | $238.38 |
| Massachusetts | 28.8¢ | $0.86 | $26.32 | $315.58 |
| Michigan | 22.0¢ | $0.66 | $20.10 | $241.01 |
| Minnesota | 16.9¢ | $0.51 | $15.48 | $185.60 |
| Mississippi | 16.2¢ | $0.48 | $14.76 | $176.95 |
| Missouri | 13.7¢ | $0.41 | $12.49 | $149.80 |
| Montana | 14.7¢ | $0.44 | $13.40 | $160.64 |
| Nebraska | 13.6¢ | $0.41 | $12.41 | $148.81 |
| Nevada | 13.6¢ | $0.41 | $12.42 | $148.92 |
| New Hampshire | 27.3¢ | $0.82 | $24.96 | $299.26 |
| New Jersey | 23.3¢ | $0.70 | $21.25 | $254.81 |
| New Mexico | 14.1¢ | $0.42 | $12.89 | $154.61 |
| New York | 29.9¢ | $0.90 | $27.33 | $327.73 |
| North Carolina | 15.1¢ | $0.45 | $13.78 | $165.24 |
| North Dakota | 13.6¢ | $0.41 | $12.43 | $149.03 |
| Ohio | 19.5¢ | $0.59 | $17.83 | $213.74 |
| Oklahoma | 13.4¢ | $0.40 | $12.22 | $146.51 |
| Oregon | 16.3¢ | $0.49 | $14.86 | $178.16 |
| Pennsylvania | 21.6¢ | $0.65 | $19.68 | $235.97 |
| Rhode Island | 29.5¢ | $0.88 | $26.90 | $322.59 |
| South Carolina | 16.2¢ | $0.49 | $14.78 | $177.17 |
| South Dakota | 15.7¢ | $0.47 | $14.36 | $172.24 |
| Tennessee | 14.5¢ | $0.43 | $13.21 | $158.45 |
| Texas | 16.4¢ | $0.49 | $15.01 | $180.02 |
| Utah | 13.0¢ | $0.39 | $11.84 | $141.91 |
| Vermont | 24.9¢ | $0.75 | $22.73 | $272.55 |
| Virginia | 17.6¢ | $0.53 | $16.08 | $192.83 |
| Washington | 14.9¢ | $0.45 | $13.65 | $163.70 |
| West Virginia | 16.8¢ | $0.50 | $15.34 | $183.96 |
| Wisconsin | 19.7¢ | $0.59 | $18.03 | $216.15 |
| Wyoming | 14.8¢ | $0.44 | $13.52 | $162.06 |
How to cut the cost
- Put it on an outdoor-rated timer set to start three to four hours before you drive.
- Skip it entirely in mild conditions; block heaters matter well below freezing, not at 40°F.
- Check the cord and plug each season — damaged cords are both a safety and an efficiency problem.
Compare with related appliances
Monthly cost at typical usage and 19.4¢/kWh.
Questions
How long should you leave a block heater plugged in?
About three to four hours is enough for most engines. Leaving it plugged in overnight roughly doubles or triples the cost with little additional benefit.
How do you calculate what an engine block heater costs to run?
Multiply its wattage by the hours it runs per day, divide by 1,000 to get kilowatt-hours, then multiply by your electricity rate. For an engine block heater: 750 W × 4 h ÷ 1,000 = 3.00 kWh per day, which at 19.4¢/kWh is $0.58 per day.
How many watts does an engine block heater use?
Typically 750 watts, with most models falling between 400 and 1,500 watts. The label on the appliance or its power supply gives the figure for your specific unit.