What an engine block heater costs to run, overnight or on a timer
Last updated · Prices: U.S. EIA, August 2026
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A 1,000 W block heater left plugged in for 10 hours costs $1.82 a night at the U.S. average electricity price. An engine only needs about 2 hours of heat before a cold start, so a timer cuts that to $0.36, 80% less, or $43.58 saved over 30 nights.
Cost per night by heater size, at the U.S. average of 18.16¢ per kWh
The wattage is printed on the heater or its cord.
| Heater | Overnight (10 h) | Timer (2 h) | Saved / 30 nights |
|---|---|---|---|
| 400 W | $0.73 | $0.15 | $17.43 |
| 600 W | $1.09 | $0.22 | $26.15 |
| 750 W | $1.36 | $0.27 | $32.69 |
| 1,000 W | $1.82 | $0.36 | $43.58 |
| 1,250 W | $2.27 | $0.45 | $54.48 |
| 1,500 W | $2.72 | $0.54 | $65.38 |
Cost in every state
For a 1,000 W heater, most expensive first.
| State | Price/kWh | Overnight | Timer | Saved / month |
|---|---|---|---|---|
| Hawaii | 47.18¢ | $4.72 | $0.94 | $113.23 |
| Maine | 32.11¢ | $3.21 | $0.64 | $77.06 |
| Massachusetts | 30.48¢ | $3.05 | $0.61 | $73.15 |
| California | 29.75¢ | $2.97 | $0.60 | $71.40 |
| Alaska | 29.41¢ | $2.94 | $0.59 | $70.58 |
| New York | 28.65¢ | $2.87 | $0.57 | $68.76 |
| Rhode Island | 28.18¢ | $2.82 | $0.56 | $67.63 |
| New Hampshire | 27.64¢ | $2.76 | $0.55 | $66.34 |
| District of Columbia | 25.98¢ | $2.60 | $0.52 | $62.35 |
| New Jersey | 24.61¢ | $2.46 | $0.49 | $59.06 |
| Connecticut | 24.51¢ | $2.45 | $0.49 | $58.82 |
| Vermont | 23.84¢ | $2.38 | $0.48 | $57.22 |
| Michigan | 22.99¢ | $2.30 | $0.46 | $55.18 |
| Pennsylvania | 21.77¢ | $2.18 | $0.44 | $52.25 |
| Maryland | 21.40¢ | $2.14 | $0.43 | $51.36 |
| Ohio | 19.38¢ | $1.94 | $0.39 | $46.51 |
| Wisconsin | 19.41¢ | $1.94 | $0.39 | $46.58 |
| Illinois | 19.32¢ | $1.93 | $0.39 | $46.37 |
| Delaware | 18.70¢ | $1.87 | $0.37 | $44.88 |
| Virginia | 17.64¢ | $1.76 | $0.35 | $42.34 |
| Colorado | 17.17¢ | $1.72 | $0.34 | $41.21 |
| Minnesota | 17.20¢ | $1.72 | $0.34 | $41.28 |
| Iowa | 17.06¢ | $1.71 | $0.34 | $40.94 |
| Indiana | 17.02¢ | $1.70 | $0.34 | $40.85 |
| New Mexico | 16.51¢ | $1.65 | $0.33 | $39.62 |
| Alabama | 16.33¢ | $1.63 | $0.33 | $39.19 |
| West Virginia | 16.31¢ | $1.63 | $0.33 | $39.14 |
| Missouri | 16.02¢ | $1.60 | $0.32 | $38.45 |
| Georgia | 15.90¢ | $1.59 | $0.32 | $38.16 |
| Oregon | 15.92¢ | $1.59 | $0.32 | $38.21 |
| Texas | 15.91¢ | $1.59 | $0.32 | $38.18 |
| South Carolina | 15.76¢ | $1.58 | $0.32 | $37.82 |
| Montana | 15.57¢ | $1.56 | $0.31 | $37.37 |
| Kansas | 15.47¢ | $1.55 | $0.31 | $37.13 |
| South Dakota | 15.15¢ | $1.52 | $0.30 | $36.36 |
| Arizona | 15.05¢ | $1.51 | $0.30 | $36.12 |
| Florida | 14.99¢ | $1.50 | $0.30 | $35.98 |
| North Carolina | 14.95¢ | $1.50 | $0.30 | $35.88 |
| Oklahoma | 14.82¢ | $1.48 | $0.30 | $35.57 |
| Washington | 14.63¢ | $1.46 | $0.29 | $35.11 |
| Arkansas | 14.37¢ | $1.44 | $0.29 | $34.49 |
| Mississippi | 14.43¢ | $1.44 | $0.29 | $34.63 |
| Wyoming | 14.43¢ | $1.44 | $0.29 | $34.63 |
| Kentucky | 13.80¢ | $1.38 | $0.28 | $33.12 |
| Nebraska | 13.54¢ | $1.35 | $0.27 | $32.50 |
| Idaho | 13.37¢ | $1.34 | $0.27 | $32.09 |
| Tennessee | 13.42¢ | $1.34 | $0.27 | $32.21 |
| North Dakota | 13.31¢ | $1.33 | $0.27 | $31.94 |
| Utah | 13.31¢ | $1.33 | $0.27 | $31.94 |
| Louisiana | 12.87¢ | $1.29 | $0.26 | $30.89 |
| Nevada | 12.72¢ | $1.27 | $0.25 | $30.53 |
Assumes the heater draws its rated wattage the whole time it is plugged in. Prices are EIA's preliminary average residential figures for August 2026; your utility's rate may differ.
Why two hours is enough
Wisconsin Public Service says The typical engine block heater takes just 1 to 2 hours to raise a tractor engine to temperature for starting.
Guidance credited to Natural Resources Canada is blunter: Help reduce the impact of cold starts by using a block heater - two hours is more than enough.
The same utility's example assumes a heater that runs 10 hours per day (overnight typically)
, which is the gap a timer closes. Wisconsin Public Service puts a plug-in timer for a 120 volt heater at about $20.
How the cost is worked out
Cost per night is the heater's wattage in kilowatts, times the hours it is plugged in, times your price per kWh. A 1,000 W heater uses 10 kWh over 10 hours and 2 kWh over 2. For your state's price, see electricity cost by state; for other winter loads, see what a space heater costs to run.
Frequently Asked Questions
- How much does it cost to run an engine block heater?
- A 1,000 watt block heater costs $1.82 a night if it is left plugged in for 10 hours, at the August 2026 U.S. average of 18.16¢ per kWh. On a timer that runs it for the 2 hours before you leave, the same heater costs $0.36.
- How long should I plug in my block heater?
- About 2 hours. Wisconsin Public Service says a typical block heater takes 1 to 2 hours to bring an engine up to temperature, and guidance credited to Natural Resources Canada says two hours is more than enough. Leaving it plugged in all night uses more electricity than that warm-up needs.
- How much does a block heater timer save?
- Running a 1,000 watt heater for 2 hours instead of 10 cuts its electricity use by 80%, which saves $1.45 a night or $43.58 over 30 nights at the U.S. average price. Wisconsin Public Service puts a plug-in timer for a 120 volt heater at about $20.
- How many watts is a block heater?
- Common sizes run from 400 to 1,500 watts; Wisconsin Public Service's savings table lists 400, 600, 750, 1000, 1250, 1500 watt heaters and uses 1,000 watts as its example. The wattage is printed on the heater or its cord, so check yours.
Link to this calculator
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Sources
- Wisconsin Public Service: Tractor heater timers (warm-up time, overnight hours, heater sizes, timer price)
- City of St. Albert, Alberta: Idle free (source: Natural Resources Canada)
- U.S. Energy Information Administration: Electric Power Monthly, Table 5.6.A (August 2026, residential)