How Long Do Generators Last? (+ Essential Maintenance Tips)

Power outages are not just bothersome intruders on your family movie night plans but can also be unwelcome setbacks to getting work done. Generators are reliable sources of backup power, but they can also be costly, as I have recently discovered. So, how long will your shiny new generator last?

Portable generators will generally last between 1000 and 2000 hours, whereas standby generators can last 3000 hours or more. Assuming you use your generator for 100 hours per year, it will last between 10 and 30 years or even longer if you maintain it properly.

To give you a better understanding of the lifespan of a generator, we will look at the following:

  • How long will your generator last?
  • What factors affect a generator’s lifespan?
  • Is it time to replace your generator?

Buying a generator isn’t just a once-off, quick fix to your power problems. If you want to get a long life out of your generator, you will need to follow our steps to look after it.

Open generator showing the motor and engine

How Long Will Your Generator Last?

Not all generators are made equal, and there is a substantial difference in lifespan between backup and portable generators. However, there is also a considerable price difference between the two.

What Is The Lifespan Of Backup / Standby Generators?

On average, a standby generator should last you 3000 running hours, or 30 – 40 years, depending on how often you use it.

A standby- or backup generator is a permanent fixture outside your home. It is usually specified to be able to run your entire home uninterrupted and will typically automatically turn on should there be a power outage.

In the arena of standby generators, you also have different options of fuel sources, ranging from LP gas, propane to diesel. Propane and diesel generators should last you slightly longer than LP gas options, so keep that in mind when shopping around.

For a more exact lifespan estimation, you can take the average number of blackouts you have to deal with per year, how long they usually last, and then add maintenance hours.

Example Lifespan

For example, if you have five blackouts per year, each lasting 15 hours, you need to generate 65 hours. Add 15 hours for maintenance runs, and you are going to run your generator an estimated 80 hours per year, which means you could get 37.5 years of use out of your standby generator.

I have seen one source claiming diesel generators generally last between 10 000 and 30 000 hours, but it seems far removed from the rest of the consensus. That being said, proper maintenance can definitely extend its lifespan, and some manufacturers even offer extended warranty options.

What Is Lifespan Of Portable Generators?

Portable generators typically have a shorter lifespan than backup generators, lasting between 1000 – 2000 hours.

As the name suggests, portable generators aren’t fixtures and aren’t customized to suit your power needs. Instead, they can be considered the “quick and dirty” backup power solution.

Portable generators don’t switch on automatically unless you have had a custom auto-switch added.

Cord Life

Should you need to use your generator, you will be starting by yourself. Hopefully, you have one with an electric starter instead of the old pull cord. Also, depending on your setup, you have to change over the power source on your switchboard manually.

Furthermore, portable generators will not give you the same power output as standby generators, which means you will not be able to power your entire home on them.

Instead, you will use it to run a few selected emergency appliances, like the WiFi. Trust me; you don’t want to leave your family in the dark without WiFi.

Portable generators will be mostly gasoline-powered, with some manufacturers offering diesel fuel options.

They usually have a 1000-hour shorter lifespan than standby generators, with most lasting between 1000 – 2000 hours. This means that your portable generator should last you around 10 to 20 years on a 100 hour per year use, ten years less than the standby generator.

What Do Standby And Portable Generators Cost?

You may be thinking that the longer life span, less effort, and greater power of the standby generator make this a no-brainer option for you, but you have to consider the price difference.

Depending on size and manufacturer, portable generators will cost you between $200 and $5000. On the other hand, standby generators start at around $7000, excluding installation costs.

If you are handy, you can maintain your portable generator yourself, while you will need a professional to service that big standby generator, adding even more cost.

What Factors Affect Your Generators Lifespan?

As with just about anything you own, you can do a few things that will extend your generator’s lifespan and, inversely, shorten if you don’t take care of it.

1. Properly Maintaining And Repairing Your Generator

Proper and regular maintenance is the most significant contributor to the lifespan of a generator.

Remember that a generator is essentially a motor, and much like the motor of your car, you need to take care of it if you want it to last. Therefore, your generator is going to require short- and long-term attention.

Short-Term Generator Maintenance

For the short-term, you need to run your generator, under load, every week for 15 to 20 minutes.

If you have a standby generator, switch the power over to the generator once a week and if you have a small portable, use it to boil a kettle of water every week.

This weekly run allows the generator to stretch its legs and open its lungs. As a result, the oil will heat up and flow through all the components and keep them lubricated. It also allows you to see if it is in good working condition.

Draining Fuel

A pro tip for carbureted portable generators is to shut off the power output and let it run out of gas instead of switching it off. Then, the extra fuel in the carburetor bowl will be burnt rather than becoming a slimy mess, should you forget to run your generator for a while.

Once a month, you should also do a fluid level check, ensuring that the oil and coolants are topped off. Use the opportunity to check the air filter and clean out any debris from the filter and your generator’s housing.

Leaves and dirt will likely have accumulated on the generator housing, potentially blocking crucial air intakes.

Long-Term Generator Maintenance

Long-term maintenance should happen once or twice a year.

You will want to get a technician twice a year to do this maintenance on standby generators. They will run the generator for a few hours every six months and check that everything is in working order.

Every 12 months, they will replace everything that needs replacing, such as the oil, spark plugs, filters, etc., and conduct any other needed maintenance. In addition, many dealers will offer maintenance package options with their generators. A good idea if you are buying a standby generator.

You will want to service a portable generator at least once a year. If your monthly checks don’t show signs of low fluids or degraded filters, a once-a-year service should keep her running smoothly.

Spark Plugs

Most generators have a prescribed maintenance schedule showing you how many hours you can run it before it needs an oil change, sparkplug change, etc. However, I prefer to replace all the consumables on my generator at least annually, even if I haven’t reached the stipulated usage hours.

As I mentioned above, if you’re savvy around small-form motors, such as lawnmowers, you’ll be able to do the maintenance yourself. However, if you encounter a sound or problem you can’t diagnose, it’s best to take your generator to a technician before you use it again.

2. Buying The Right Sized Generator

One of the contributing factors to the shorter lifespan of portable generators is that people tend to overload them, expecting them to pull the weight of a standby generator. However, constantly running your generator at its maximum output will strain it and shorten its lifespan.

You can avoid this by identifying which appliances you need to run off your portable generator and purchasing one that is large enough to cope with that load. You can even use a generator size calculator from the manufacturer.

If you are purchasing a standby generator, chances are you will have it professionally specified and installed, so you should be OK when it comes to power output size.

Keep in mind that if you already own a standby generator, you have probably upgraded or added appliances at some point. Just check that you don’t add too many and overpower your generator.

3. Placing Your Generator In The Correct Space

Ideally, you don’t want to place your generator close or under vegetation that will grow in and over it or attract various forms of wildlife to inhabit its open cavities.

It may be tempting to place your generator as far as possible from your home, under some obscure tree in the corner, to try and drown out the noise. However, leaving your generator exposed to the elements is a sure way to shorten its life.

Place your generator somewhere it is protected from the elements, from plant debris, and where it has access to unrestricted airflow. For standby generators, the technicians should be able to advise you on proper placement in your yard.

It would be best to keep your portable generator inside your house unless it’s in use or in an enclosure made to house it outside. However, when you run the generator, you should move it out where it can breathe.

If you run your portable generator in an enclosed space with no airflow, you will do irreparable damage.

4. Breaking In Your Generator

Breaking in a motor follows the manufacturer’s guidelines during the first few uses to ensure that the piston rings wear into the piston chamber walls, creating a fingerprint-like symbiosis and seal.

Some manufacturers break in their motors on the assembly line, but others will require, for example, running them without any load for an hour or two. Make sure that you check the manufacturer’s specifications on breaking in your generator, as doing so could extend its lifetime.

How Long Can You Run Your Generator?

You may have wondered how long you can run your generator without a break, but unfortunately, there isn’t a single set answer.

In most cases, your runtime will depend on the size of your fuel tank and your consumption. Standby generators usually have a tank capacity of 24 to 72 hours, and ideally, if you have run out of fuel, you should let the motor cool down before refueling.

On the other hand, natural gas generators eliminate the need to refuel them when connected to a gas line. However, most manufacturers recommend not running them for longer than 500 hours at once.

Portable generators are limited by the fact that they usually are not actively cooled, meaning that they can overheat quicker than standby generators.

If you are using a gasoline generator, you can expect to get 6 – 8 hours of use, after which you must let it cool down entirely before refueling.

Is It Time To Replace Your Generator?

Perhaps you are reading this because you have wondered whether it is time to upgrade or replace the old genny you inherited from Grandad. Here are three telltales that it’s time to replace your generator:

1. Your Generator Is Too Small

If your generator has become too small for your needs, you may risk overuse.

While this may not seem like enough reason to replace your generator, it is one that you should seriously consider.

If your generator can no longer meet your power consumption needs, you have three options:

  1. Overwork your generator and run it to death
  2. Lower your power needs and use fewer appliances during a blackout, or
  3. Sell your generator and use the funds toward buying a bigger one.

If you can sell your generator and get some money toward the new one, it makes a lot more sense than pushing your current generator to its limits, breaking it and your appliances in the process, and needing to start over.

2. Your Generator Has Worked Hard

You may very well be proud that you have gotten 10 000 hours out of your generator by doing proper maintenance and looking after it. And while it truly is something to be proud of, there comes the point where a captain needs to let a ship sink or go down with her.

Despite being well looked after, a generator with too many hours on the clock is running on borrowed time and may fail you when you need it most.

Its age will have compromised its ability to generate high-quality, consistent power output, meaning that you either won’t get its total capacity or could damage your appliances.

3. Your Generator Constantly Needs Repairs

As soon as you need a technician more often than usual, it may be time to buy a new one.

One sign will be a domino effect of breakages, meaning that as you fix one problem, you identify another problem, leading to another, etc.

General signs of wear and tear normally foreshadow the point of constant repairs. For example, if you notice regular oil leaks, fragile wiring, excessive rust, or other pervasive issues, you should probably save the money for the technician and replace it.


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