Backup generator maintenance

The maintenance schedule is short and it matters more than the brand you picked. Oil after about 30 hours on a new portable and roughly every 100 hours after that. Air filter at a year or 100 hours, sooner in dusty conditions. Spark plug annually or at 100 hours. A professional check every two years or 200 hours, which should include testing the electrical circuitry and inspecting the transfer switch.

At $80 to $300 per visit, service is cheap next to a $5,090 average install. The failure mode people actually experience isn't a worn-out generator — it's a perfectly good generator with a dead battery and a year-old air filter that won't carry the house at 2 a.m.

Exercise cycles. Standby generators typically start themselves weekly and run for several minutes. Five to ten minutes is enough. Learn your unit's day and time. If you have a portable with fuel in the tank, start it manually every two weeks for the same reason.

A well-maintained standby unit is generally expected to last at least 20 years. That figure assumes the schedule above was actually followed, not that the machine was left alone and got lucky.

How to choose

Keep a log by the unit

Date, hour meter reading, what was done. It settles warranty arguments and it tells the next tech what they're walking into.

Ask what the service plan actually includes

A plan that's just an oil change at $250 is worse value than a $180 visit that includes a battery load test and a transfer switch inspection.

Don't skip the transfer switch check

Bob Vila notes professional service should include inspecting the transfer switch. It is the component most likely to leave you dark with a running engine.

Use stabilizer instead of leaving raw fuel

For portables stored a few months, manufacturers may recommend an additive to stop the fuel varnishing rather than draining the tank.

Confirm the exercise cycle after any service

Techs sometimes leave a unit in manual or off. Watch for the next scheduled self-test after every visit.