How Long Will a Generator Last?

Generators are an essential prep for long and short-term survival situations alike. Natural disasters, accidents, bad weather and societal strife can all knock out power to your home and when that happens the only thing that can reliably power the appliances and tools you need will be your trusty generator.

a gas generator
a gas generator

And throughout your life you’ll have cause to use your generator periodically for mundane events, too. Like any machine, a generator can wear out. How long can you expect your generator to last?

Your generator should last 20 to 30 years. More precisely, between 1,000 hours and 3,000 hours of runtime depending upon its type, quality, and other factors.

Generally, portable generators do not last as long as built-in standby generators, and generators that are run hard at nearly maximum output will wear out quicker than ones run gently below their maximum capacity.

Generators are expensive, and maximizing the return on your investment is an important consideration. You’ll also need to get the most bang for your buck concerning ongoing maintenance and replacement costs. Below we will discuss several factors that impact the service lifespan hours of your generator.

Generator Type

Probably the most salient factor that determines the lifespan of the generator is the same one that determines what you are buying it for. Most consumer grade generators come in one of two varieties: Portable and standby.

Portable generators are the ones you usually find at job sites, campsites, and any other location where tools and lights requiring steady, dependable electrical power are being used and there is no reliable or easy way to access the electrical grid.

These generators are sometimes man packable and sometimes installed on small, wheeled carts.

Standby generators are larger, immobile or only semi portable once dismantled and designed to supply power quickly to a structure or fixed installation once primary power is lost.

These are the generators you see installed next to typical residential homes, especially in storm prone areas, or places where disruption of electricity is frequent.

Of the two, stand-by generators typically last longer, all other factors being equal, with a service life anywhere between 2,000 and 3,500 hours. Portable generators, on the other hand, usually have a service life measured between 1,000 and 2,000 hours.

Usage Tempo

A generator that is used more often will accumulate uptime hours more quickly than one that is used infrequently. More uptime means reaching end of service life faster, so accordingly you should plan your generator purchase concerning your anticipated usage tempo.

An installed standby generator that is only run for 72 hours a year on average, not including a short, quick weekly startup for testing, could it last a very long time indeed if the service life is rated at 2,000 hours.

Conversely, a portable work site generator with a service life rated at 750 hours could be burned up in a little more than a year if it is being run for 15 hours each week.

A higher usage tempo will also necessitate more maintenance, maintenance that is all too easy to defer or put off, in effect further accelerating degradation. A high quality generator that is rarely used but lovingly maintained may very well last your entire life.

Operative Capacity

Running any generator at or near capacity decreases its service life. This is because the engine will be running near the very limits of its mechanical capability. If you were relying on a small generator to power multiple appliances and tools in the middle of an emergency situation, it is going to be working very hard indeed.

But if you were to be running those same appliances on a larger, more powerful generator with capacity to spare the engine will not be working as hard and will, even under the exact same load and usage tempo, last longer, all other factors being equal.

You should make it a point to load your generators lightly, and only run them at or near maximum capacity for a limited period of time, and only when you have no other choice.

Accordingly, choose your generator wisely when purchasing and don’t make the amateur mistake of buying the smallest generator that will cover your anticipated power demands by a narrow margin in an effort to save money. The loss of capability and increased maintenance intervals will rapidly offset any upfront cost savings and the decrease in overall service life will have the effect of making your hourly cost of generating electricity even higher.

Maintenance Intervals

The condition of a generator is critical to good performance, and each variety has its own prescribed maintenance checks and procedures that must be performed if efficiency is to be maintained.

Generators that are poorly maintained and tuned are less efficient and have to work harder to produce the same amount of power, shortening their service life.

As expected, a generator that is carefully maintained will not work as hard and accordingly will not wear out as quickly.

Staying on top of generator maintenance is critical, but often deferred because professional maintenance costs money and most folks don’t want to spend on it especially when it is a standby generator that is rarely if ever used.

A generator that is in an extremely poor state of repair is unlikely to run for very long at all, and assuming you can get it running the service life can probably be measured in the double-digit hours if that.

Exposure to Elements

Exposure to the elements is another factor that will degrade the service life of a generator, and it is also one of the most insidious since many generators are by design installed in place outside of any protective structure.

Rain, dust, wind, insects, and more all have a negative effect on generator components, effects that should be ameliorated by periodic maintenance. And you are doing periodic maintenance, right?

This is usually a bigger concern for portable generators that naturally sit outside in the weather when doing their jobs, but standby generators that are not installed in a proper generator shed are similarly vulnerable even with their protective covers in place.

It is always a good idea to store any generator not in use in a mild, dry environment safe from the questing explorations of rodents and insects. If this is not possible, make sure you periodically inspect your generator for exposure-related wear and correct any issues before they get out of control.


An average generator can be expected to last anywhere between 1,000 hours and 3,000 hours depending on its type, quality and other salient factors.

As expected, cheap generators will not last as long as more expensive versions, typically, and a hard usage schedule and high operational tempo will accelerate the retirement of any generator. Staying on top of maintenance and running a generator well below its listed capacity is a great way to extend its lifespan.

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