Standby generator maintenance checklist
Updated August 2026
A standby generator mostly maintains itself between visits: let the weekly self-test run and watch for a fault light, then change the oil and filter once a season or every 100 to 200 run hours, whichever comes first. Keep the enclosure clear, the battery charged, and the cold-weather kit working. A pro service contract runs $300–500 a year, and a well-kept unit lasts 10 to 30 years.
| Task | Interval | Effort |
|---|---|---|
| Confirm the self-test ran and cleared | Weekly (automatic) | 1 min · DIY |
| Check the controller for warning lights | Weekly | 1 min · DIY |
| Task | Interval | Effort |
|---|---|---|
| Look over the enclosure for pests, nests, and debris | Monthly | 5 min · DIY |
| Verify the battery charger and connections | Monthly | 5 min · DIY |
| Task | Interval | Effort |
|---|---|---|
| Change the oil and oil filter | Seasonal / 100–200 hrs | $20–40 DIY |
| Replace the air filter and check the spark plugs | Yearly | $30–60 DIY |
| Inspect the transfer switch and wiring | Yearly | $150–300 pro |
| Task | Interval | Effort |
|---|---|---|
| Replace the starting battery | 2–3 years | $40–120 |
| Have a pro load-bank and combustion test it | Every 2 years | $150–300 pro |
What neglect costs
The cruel part is that a neglected standby unit usually fails on the exact night you need it. A dead starting battery is the number-one no-start cause, and a unit that has not had its oil changed on schedule or its weekly exercise cycle left running can seize or stall under load. The bill for that outage is a fridge and freezer of spoiled food ($300–500), a hotel stay, or in winter a burst pipe running into the thousands. A yearly service at a fraction of that keeps it honest.
Leave these to a pro
The annual or twice-yearly professional service ($300–500 a year on contract) is the part worth paying for: a tech load-tests the generator, checks the automatic transfer switch, verifies fuel pressure and combustion, and updates the controller. Transfer-switch and gas-line work is not DIY at all, it is 240-volt and fuel under a house. Oil, filters, and the battery you can handle between visits, but let the pro certify that the whole start-to-load sequence actually works before storm season.
This whole checklist ships as reminders in OnOtto: every task above, on the right schedule for your home, snooze-proof.
Load this checklist as remindersFrequently asked questions
How often should a standby generator run its self-test?
Most whole-home units are set to exercise once a week for 5 to 20 minutes, though some newer models run a shorter, quieter monthly or biweekly cycle to save fuel. The point is the same: circulate oil, charge the battery, and burn off condensation so the engine is ready. Do not disable it just to stop the noise. If you never hear it run, that is a warning sign in itself, so check the controller and the exercise schedule.
Why won't my standby generator start during an outage?
The most common answer is the battery: like a car, a standby generator cranks off a 12-volt battery that dies at 3 to 5 years and gives no warning. After that, suspect stale fuel in a gasoline unit, a tripped controller, a closed fuel valve, or a failed transfer switch. Natural-gas and propane units dodge the fuel-staleness problem, which is one reason they dominate. If the weekly exercise has been running clean, a genuine no-start is far less likely.
Can I change the oil in my standby generator myself?
Yes, and it is the maintenance that most rewards doing on time. Change it after the first 25 hours of a new unit, then every 100 to 200 run hours or once a season, using the weight the manual specifies (often synthetic 5W-30). Budget $20 to 40 in oil and a filter. Do it with the unit cool and the automatic start disabled so it cannot crank while your hands are in it. Keep the receipts, since some warranties want proof of service intervals.