How Long Do Generators Last?

Today we’re going to answer the question : How long do generators last?

I recently decided to look into answering on of the most common questions that people ask about generators : How long portable generators last? Unfortunately, the information isn’t easy to find. It was only when I started looking at standby generators that I found manufacturers such as Generac who provide a lot of information about their generators for consumers. Using Generac as a starting point, you can expect their engines to last up to 3,000 hours (on average). They claim their engines last about 3x as long as the competition.

Let’s dig a little deeper into generator longevity. I think you’ll be surprised at how long a well-maintained quality generator will actually last.

How Long do Generators Last?

Using this statement as a starting point, you can expect typical portable generators to last 1,000 to 2,000 hours. I also discovered that several manufacturers offer full support under warrantee for portable generators up to 1,000 hours runtime. Manufacturers are obviously not going to do this unless they expect their generators to last longer, with the correct maintenance. We can, therefore, expect a well-maintained generator to last longer than 1,000-hours. Possibly twice as long.

Generac calculated a typical usage example for their generators, based on average standby generator use. They used an example of a generator that regularly starts for a self-test, running at low RPM for a short time. At eleven hours per year for weekly testing, plus four power outages of twenty hours each, it equals 91-hours of operation per year. If we assume that the engine is expected to last for at least 3,000-hours, it should be good for 33-years

Using the Generac logic, I did the math for a portable generator with an engine life expectancy of 2,000-hours. It should last for 22-years or more. I read many claims that generators can last from 10,000 to 30,000 hours, but these are unsubstantiated. If this were true, a generator that runs for an average of 100-hours per year, should last for 300-years. I think we can all agree that this is totally unrealistic.

Surely, a generator that lasts 20 to 30 years will satisfy most owners. I consider that to be an excellent life expectancy, no-one expects to use a car for that long. In another comparison, 3,000 hours on your car engine, at an average speed of 70 mph, will clock 210,000 miles over this time. You can expect your generator to outlive the lawnmower, pool equipment, and most appliances in the home. With proper maintenance and care, it can even last longer.

To ensure that your generator lasts that long, it’s important to choose a good brand. A reputation for quality build and durability, should mean a longer lifetime. Even though these generators cost more, the extended lifetime is worth the extra money. Regular maintenance is also important if you expect your generator to last longer. Only use high-quality fuel and oil; and protect it against dust buildup and damp.

You will most likely replace your generator before it reaches the end of its useful life. Changes in the technology, like brushless and inverter generators, already make older models less desirable. Regulation changes, like those for emission and noise levels, may force you to replace your generator sooner. Clean power alternatives, like battery backup systems for residential use, are becoming more affordable. These may soon be a viable alternative to gas-powered generators.

Some Maintenance Issues

So far, I’ve focused entirely on engine life because the engine endures the most of the mechanical stress. Generally, the alternator and other electrical components outlast the engine. These components may fail, but replacing electrical components is usually part of general maintenance. A generator cannot be considered redundant when all it needs is replacement service parts.

The main enemy of electrical components is a buildup of dust and condensation. This can cause insulation on the field windings to deteriorate, resulting in a short circuit. Excessive moisture promotes rust formation and pitting. Connections become corroded and do not make proper contact. All these issues are preventable with proper maintenance and storage.

VIDEO | Step-by-Step Guide on Generator Maintenance

A generator will last longer if you examine and clean critical components as part of your monthly and yearly maintenance. Preventative maintenance requires more than just changing the oil. It includes removing water from your fuel tank and replacing filters throughout your generator. Following manufacturer’s maintenance and storage recommendations will prolong the life of your generator. Generators also last longer when the power demand is not too excessive in relation to its rated load. Using a generator at maximum capacity for long periods, especially in hot weather, will increase wear and the generator won’t last as long as it should.

✔ Learn more on extending the life of your generator by reading our dedicated article : Generator Maintenance.

Stand-By vs Portable Generators

Stationary standby generators, used as a backup for commercial and many residential applications, normally use diesel and natural gas to power their engines. These generators are usually professionally installed and maintained, ensuring that they always operate under ideal conditions. Automatic controls regularly start the generator. This keeps the engine “exercised” and well-lubricated, thereby increasing their lifespan.

Large diesel generators, that run at 1,800 RPM, often last 2 to 3 times longer than gas engines that run at 3600 RPM. Inverter generators are the exception, capable of running at variable engine speed, depending on the load.  Therefore, bigger diesel units can drive four-pole generators running at slow engine speeds.

Diesel fuel is also a good top-end lubricant that lubricates valve stems and the sleeve at the top end. The low speed, and improved lubrication in the top end cylinder, ensures less wear and tear on diesel engines. It is for these reasons that the lifespan of diesel generators are longer than gas generators.

The portable generator is aimed at a different market and is usually powered by gasoline and propane. Portable generators are a lot smaller than the permanent installations and are designed to be light, easily transported, and convenient to use wherever you need power. Because a diesel engine is heavy and noisy, it is not very popular for portable generators.

Portable generators usually operate in less than ideal conditions; open spaces where they are exposed to dust and moisture. All these factors have a negative impact on the life expectancy of the portable generator.

Most generators use splash lubrication, which makes the engine cheaper, but is not ideal. A generator engine with pressurized lubrication, using an oil pump like a car engine, will last longer. This causes the oil to circulate immediately after starting the engine. Since a cold engine experiences the greatest deterioration, improving oil circulation during start up will prolong engine life. Pressurized lubrication is one of the main reasons why Generac claim their engines last longer, but they are not the only generator manufacturers to do this.

Tips on Generator Storage

All generator storage guidelines in user manuals will instruct you, among other procedures, to store the generator in a cool dry place. I already touched on the subject when I explained how dust and damp are the main enemies of electronic components. Storing the generator in a cool dry place helps prevent rust.

I have yet to find a generator owner’s manual that does not contain a section on storing the generator. Therefore, I urge you to read the manual and follow the instructions. The guidelines are all quite similar:

• Drain all the fuel from the system and lubricate the internals of the engine.
• Keep everything dry and dust free.
• Regularly charge the battery or use a smart charger that will maintain the battery charge.

Interesting advice, not mentioned in most manuals, is an additional step when pouring oil into the spark plug opening to lubricate the engine. They instruct you to pull the recoil starter a few times before you replace the spark plug. That piece of information is in all manuals, but some also recommend that you then pull the cord slowly, after replacing the spark plug, until you feel the compression in the cylinder. This ensures the intake and exhaust valves are closed, properly sealing the engine and protecting it against corrosion.