Most portable generators last 1,000 to 3,000 hours of run time. For a typical homeowner who uses one a few times a year, that works out to roughly 10 to 20 years. Home standby generators last much longer, usually 10,000 to 30,000 hours, or about 20 to 30 years. Inverter generators from premium brands sit at the top of the portable range, and cheaper open-frame models sit at the bottom.
How long yours actually lasts depends far more on how it’s maintained and stored than on the brand. A generator that sits with old gas in it can be ruined in a single season, while a well-kept one can outlast the house it’s protecting.
Generator Lifespan by Type
| Generator type | Typical lifespan (hours) | Typical lifespan (years of normal use) |
|---|---|---|
| Budget portable (open frame) | 1,000 to 1,500 | 8 to 12 |
| Premium portable or inverter | 2,000 to 3,000 | 10 to 20 |
| Home standby (air-cooled) | 10,000 to 20,000 | 20 to 25 |
| Liquid-cooled standby or diesel | 20,000 to 30,000+ | 25 to 30+ |
Hours matter more than years. Running a portable generator around the clock for two weeks after a hurricane puts over 300 hours on it, about as much as several years of occasional use. If your generator doesn’t have an hour meter, an inexpensive add-on meter makes tracking oil changes and wear much easier.
What Shortens a Generator’s Life
- Old fuel. This is the most common killer. Gasoline starts breaking down within a month or two and gums up the carburetor. Use fuel stabilizer, or run the carburetor dry before storage.
- Skipped oil changes. Small air-cooled engines run hot and are hard on oil. Most manufacturers call for the first change after the 20 to 30 hour break-in period and every 50 to 100 hours after that.
- Running overloaded. Constantly pushing a generator near its maximum wattage wears the engine and alternator faster. Aim to stay under about 75% of rated watts for long runs.
- Moisture and rust. Rain, flooding and humid storage corrode wiring and engine parts. Keep it covered and dry, and see whether generators can get wet before running one in bad weather.
- Sitting unused. A generator that never runs can have dried-out seals, a dead battery and a stuck carburetor right when you need it.
How to Make Your Generator Last Longer
- Break it in properly and change the oil after the first 20 to 30 hours.
- Change the oil on schedule after that, using the type your manual specifies. Our guide to which oil a generator uses covers the common choices.
- Add fuel stabilizer to every can of gas, or drain the fuel before storing it for more than a month.
- Start it and run it under a light load for 15 to 20 minutes once a month.
- Clean or replace the air filter and check the spark plug every season.
- Keep the battery charged on electric-start models.
- Store it somewhere dry and covered, off the ground.
- Don’t overload it, and let it cool before refueling.
For a full checklist, see our generator maintenance tips.
Signs Your Generator Is Wearing Out
- It’s getting harder and harder to start, even with fresh fuel and a new spark plug.
- It surges, hunts, or can’t hold steady power under a load it used to handle.
- It burns oil or blows blue or black smoke.
- Output voltage is low or appliances flicker.
- It knocks, rattles or leaks.
Many of these problems come from the carburetor or fuel system, which is cheap to fix. Our guide to common reasons a generator won’t start is a good first stop.
Repair or Replace?
Repairing usually makes sense when the fix is a carburetor, spark plug, recoil starter, battery or fuel line, and parts are still available. Replacing usually makes sense when the engine has low compression or a damaged crankshaft, the repair costs more than half the price of a new unit, or the generator no longer fits your power needs. Newer models also tend to be quieter, more efficient and safer, and many now include automatic carbon monoxide shutoff.
Related guides: How to Clean Your Generator in 11 Easy Steps, How to Transport a Generator Safely and How to Winterize a Generator.
FAQ
How many hours will a portable generator last?
Most portable generators are built for 1,000 to 3,000 hours. Budget models are at the low end, and well-maintained premium inverter generators are at the high end.
How long does a standby generator last?
A properly maintained home standby generator typically lasts 10,000 to 30,000 hours, which is usually 20 to 30 years since they only run during outages and weekly self-tests.
Is it worth fixing an old generator?
Often, yes. Most failures on older generators are fuel-system problems that cost little to fix. If the engine itself is worn out or parts are no longer made, replacement is usually the better value.
How long can a generator run continuously?
That depends on fuel supply and the manufacturer’s limits. Most portables need to be shut down to refuel and to change oil about every 100 hours. See our full guide on how long you can run a generator continuously.