Standby Generator Cost To Own Per Month
A standby generator costs money even when the power never goes out. Enter its size, its weekly exercise, its standby draw and your maintenance plan, pick your state, and see the yearly and monthly cost of owning it.
Standby generator cost to own
E05Scenario A
Sets the electricity rate. Pick US average if you're not sure.
From EIA for US average. Use the rate on your bill if you know it.
Rate used: 18.4¢/kWh · US average · EIA reference 2025–26 · propane $2.60/gal (data as of 2026-09-26) ·
Cost to own per year, before any outage
About $33.21 a month just to keep it ready.
- Weekly exercise (fuel per year, priced as propane)
- $34.07
- Standby electricity per year
- $64.47
- Maintenance per year
- $300.00
- Total per year with no outage
- $398.54
Estimate. Formula and sources are under “How it works”. Change any input; the result updates as you type.
Formula
How it works
- Exercise fuel per year = exercise minutes ÷ 60 × 52 weeks × no-load fuel use × propane price (no-load fuel use = 60% of the generator's fuel use at half load)
- Standby electricity per year = standby watts × 8,760 hours ÷ 1,000 × electricity rate
- Total per year with no outage = exercise fuel + standby electricity + maintenance
- Per month = total per year ÷ 12
This is the cost of having the generator, not of using it. Fuel burned during an actual outage comes on top; the generator fuel cost calculator estimates that.
Sources: 12-minute weekly exercise from Generac's default schedule; no-load fuel use ≈ 60% of half-load use and propane fuel-use figures from manufacturer spec sheets; standby draw of 20–100 W for battery charger and block heater (spec range). Electricity rate: EIA Electric Power Monthly table 5.6.A. Propane price: EIA Heating Oil and Propane Update.
Worked example
A worked example
An 18,000 W standby generator in New York that exercises 12 minutes a week burns about $45.86 of propane a year just testing itself. Its 60 W charger and heater draw $131.40 of electricity a year at 25.0¢/kWh. Add $350.00 of maintenance and owning it costs an estimated $527.26 a year with no outage, about $43.94 a month.
Reference
By state, at the default inputs
Cost to own per year, before any outage, with this page's default inputs and each state's reference prices (EIA reference 2025–26, data as of 2026-09-26).
| US average | $398.54 | 18.4¢/kWh |
|---|---|---|
| Alabama | $392.31 | 15.5¢/kWh |
| Alaska | $432.15 | 25.0¢/kWh |
| Arizona | $391.87 | 15.0¢/kWh |
| Arkansas | $379.62 | 13.0¢/kWh |
| California | $457.99 | 32.0¢/kWh |
| Colorado | $387.51 | 16.0¢/kWh |
| Connecticut | $452.29 | 30.0¢/kWh |
| Delaware | $401.50 | 17.0¢/kWh |
| District of Columbia | $409.82 | 19.0¢/kWh |
| Florida | $394.49 | 15.0¢/kWh |
| Georgia | $388.81 | 14.5¢/kWh |
| Hawaii | $512.69 | 42.0¢/kWh |
| Idaho | $372.19 | 12.0¢/kWh |
| Illinois | $387.09 | 17.0¢/kWh |
| Indiana | $383.14 | 15.5¢/kWh |
| Iowa | $373.51 | 13.5¢/kWh |
| Kansas | $378.33 | 14.5¢/kWh |
| Kentucky | $378.31 | 13.0¢/kWh |
| Louisiana | $380.49 | 12.5¢/kWh |
| Maine | $435.66 | 26.0¢/kWh |
| Maryland | $409.82 | 19.0¢/kWh |
| Massachusetts | $448.79 | 29.0¢/kWh |
| Michigan | $397.16 | 19.5¢/kWh |
| Minnesota | $380.52 | 15.5¢/kWh |
| Mississippi | $382.68 | 13.5¢/kWh |
| Missouri | $373.07 | 13.0¢/kWh |
| Montana | $375.69 | 13.0¢/kWh |
| Nebraska | $368.26 | 12.0¢/kWh |
| Nevada | $391.87 | 15.0¢/kWh |
| New Hampshire | $440.47 | 27.0¢/kWh |
| New Jersey | $420.33 | 22.0¢/kWh |
| New Mexico | $386.63 | 15.0¢/kWh |
| New York | $433.46 | 25.0¢/kWh |
| North Carolina | $390.12 | 14.5¢/kWh |
| North Dakota | $365.19 | 11.5¢/kWh |
| Ohio | $389.27 | 16.5¢/kWh |
| Oklahoma | $373.07 | 13.0¢/kWh |
| Oregon | $387.50 | 14.5¢/kWh |
| Pennsylvania | $405.45 | 18.5¢/kWh |
| Rhode Island | $448.79 | 29.0¢/kWh |
| South Carolina | $391.87 | 15.0¢/kWh |
| South Dakota | $370.45 | 13.0¢/kWh |
| Tennessee | $384.00 | 13.5¢/kWh |
| Texas | $387.07 | 15.5¢/kWh |
| Utah | $372.19 | 12.0¢/kWh |
| Vermont | $422.95 | 22.0¢/kWh |
| Virginia | $394.93 | 15.5¢/kWh |
| Washington | $378.74 | 12.0¢/kWh |
| West Virginia | $393.62 | 15.5¢/kWh |
| Wisconsin | $388.84 | 17.5¢/kWh |
| Wyoming | $373.94 | 12.5¢/kWh |
Questions
FAQ
How much does a standby generator cost per month to own?
At US-average prices, a 22,000 W unit with 12 minutes of weekly exercise, a 40 W standby draw and $300 a year of maintenance comes to an estimated $398.54 a year, about $33.21 a month, before any outage. Maintenance is most of it.
Does a standby generator use electricity when it's off?
Yes. The battery charger runs all the time, and in cold climates a block or battery heater keeps the engine ready to start. At 40 W that's 350 kWh a year, about $64.47 at the US average rate of 18.4¢/kWh.
How much is annual maintenance?
We default to $300 a year, a typical figure for oil, filters, plugs and an inspection. Dealer plans vary. Type the price of yours.
Can I shorten the weekly exercise to save fuel?
Many controllers let you choose the exercise length or run it every other week. Follow the manufacturer's schedule: the test is what makes sure the unit starts in an outage. In the New York example, the exercise fuel is under a tenth of the yearly cost.
Natural gas or propane?
This calculator prices the exercise fuel as propane. If your unit runs on natural gas, the exercise line will usually be lower; the standby electricity and maintenance lines don't change.
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