How often should you test your backup generator?

Why bother

An untested generator won't start in the outage. Standard upkeep. Dull and cheap, and a lot less dull than whatever it's quietly preventing.

What the job involves

1. Check the unit is actually exercising itself. Most home standby generators do a self-test once a week, 15 to 30 minutes, to keep the engine turning over. Look at the control panel: it should show the schedule and sit on Auto or Ready, not on a fault. A test set and forgotten is the same as no test.
2. Be there for one run, the weekly self-test or a manual start, and just listen. It should catch quickly and run steady. A slow crank, a hard start, an odd noise, or a warning light is the unit telling you something before the outage does.
3. Once a month, get hands on it. Pull the dipstick and check the oil level, look round the housing for leaks, rust, or damage, and clear the leaves and muck away so it can breathe.
4. Every few months put a multimeter on the battery. A weak battery is the number one reason a standby unit won't start, and even a good one is done at 3 to 5 years, so plan on a new one in that window.

Do it yourself, or pay someone?

Mostly yourself: confirming the self-test, checking oil, clearing debris, and a multimeter on the battery need no real tools. Hand a pro the deeper annual service (oil and filter, full load test, valve and spark) and any no-start, about $80 to $300 a visit, or roughly $172 to $395 for a tune-up, averaging around $273.

What skipping it costs

$300 to $2,500 and up is the spread on a standby generator that quietly died between outages, depending on what rotted while it sat. The cheap end is a fresh battery, which is what kills most of them: the battery discharges, the fuel gums up, the oil breaks down, and one night the power goes and the thing it was bought for does nothing. Leave it long enough and that climbs past $2,000 into the fuel system and the engine, with a full replacement averaging around $5,090 installed at the worst of it. A monthly look and a battery check is the cheap end of that.

Signs it's overdue

• The self-test never seems to actually run, or the control panel is sitting on a fault or alert instead of Auto and Ready.
• Slow cranking, a hard start, or the engine failing a test run. That's the classic note of a dying battery, the most common reason these don't start.
• It's been more than 3 to 5 years on the original battery, or the battery looks swollen, corroded, or like it's leaking.

When to start thinking about it

No notice needed, really. Grumpty mentions it the day it comes due and that's that. Mark it done and Grumpty sets the next one, every month, so you can go back to forgetting it exists.

Questions people ask