Backup generators are a necessity for residential homes and commercial businesses alike. Yet, with the exception of knowing how to work them in an emergency situation, many people don’t know what they do or how to properly maintain them. To get you up to speed on residential backup generators, we consulted with one of our experts at Generac Power Systems – residential backup generator experts – who gave us some insight into backup generator operation and how long will a generator run.
Difference Between the Backup Generator and Standby Generator
A standby generator is designed to automatically provide electricity during a power outage. It is permanently installed at the home or place of business and automatically disconnects from utility feed wires, connects generator feed wires, and starts the generator engine when there’s an interruption in the power supply. The automatic transfer switch will detect a power failure and will automatically send a signal to start the generator.
A backup generator is designed for temporary use and primarily provides emergency battery back-up during short outages of less than three hours or in emergencies such as storms, flooding, wildfires, earthquakes, etc. Standby generators are also used when there’s an outage that lasts.
How long does a Backup generator last?
Typically, Backup generators have a lifespan of 20 to 30 years, depending on how often they run and how well they are maintained. A 30-year lifespan is possible if the generator runs only for short periods of time and it’s well maintained. The 30-year period assumes about 30 hours per month, or one hour every other day on average. It also assumes an annual maintenance visit to check belts, filters, fluid levels and most importantly replace any worn-out parts before they get permanent damage. Also, in 30-year, generators should have a reconditioning process performed every five years to clean the inside of the generator and replace any aging parts.
The average lifespan for most standby generators is about 3000 hours, which equates to running eight hours per day on an ongoing basis without maintenance visits or other breaks.
How Long Will a Standby Generator Last in an Outage?
When you take care of a Standby Generator, it can last for 5000 hours. The life span of the average generator set is 3000 hours or 8 hours per day on an ongoing basis. To estimate how long the generator will last, take into account how many hours you would like to run it per year. For example, a generator running for 20 hours at a time will last roughly 60 hours in a year. Standby generators typically last for 3 hours on a full tank of gas.
Buying a generator that will last Long
Generator lifespan varies from brand to brand and is also dependent on the frequency of use. We will happily help you select a long-lasting generator that provides backup power for your home or business. You can read our full reviews of different brand of generator.
Look for the brand that best suits your needs and budget.
Experts say to keep in mind the size of the generator you need, pressurized lubrication, and other factors that will make it last for years to come.
You can use our Generator Sizing Calculator to find out what type of generator you need.
Generator maintenance and repair
At a minimum, a generator should be serviced by a certified technician at least once a year and the oil & filters changed during that time.
Standby generators are typically used for backup power in case of an outage or emergency. It is important to keep them running as often as possible because they have engine coolant lubricating oil that needs changing every 100 hours of use.
A professional technician will check oil, spark plugs, batteries, and belt drives.
It is also important to clean your generator by yourself every month and check for loose wires. The cleaner you keep the machine, the better it will work when needed!
Just follow these easy steps:
- Make sure the engine has cooled down before doing an oil change.
- Check engine oil level monthly with a dipstick.
When to replace your generator
You will notice some signs that your generator may be in need of replacement. One sign is if the light flickers or cuts out when it shouldn’t and the other is that the engine takes a long time to start up.
The maintenance schedule for generator maintenance varies depending on how often you use it, but most are 100 hours per year which is about every 20 to 40 years.
One common sign of a worn-down generator is high fuel costs. As mechanical parts become less efficient over time, the engine must consume more fuel to produce the same amount of power. You may reach a point where you decide it’s worth buying a new generator to reduce the amount you are spending on fuel. Old generators also tend to require more maintenance.
How Long Can I Run My Generac Generator Continuously?
It varies from brand to brand but on average, for long periods you can run a Generac Generator for about 8 to 12 hours on a 50% load with a full tank.
If running on a 75% load you can expect to be able to run for about 5 hours before needing gas.
The main thing is how much load you are running. When running a load of 150 watts, you can expect to get about 13 hours before running out of gas.
The more load you put on the generator, the more fuel you consume. Well, obviously.
The generator is important. Some people think it’s only used in emergencies. But it can also be used if you have a lot of power needs like living in a big house and wanting to watch TV, for example. When figuring out how long the generator can run, you need to know its running watts and load.
How to Extend the Life of Your Backup Generator
Generators can last a long time if you take care of them. Be sure that the oil is at the right level and also be sure to keep it out of bad weather. You might need to shut the generator down every now and then. This way, the engine will cool down and it can run better. Take a look at these five tips to increase the lifespan of generators.
Regular Maintenance – Generators require regular maintenance, like engine cooling and checking the oil levels. Different parts of generators need their own type of care, so be sure to read your instruction manual for more information about how exactly you should maintain it. Doing this will ensure that your generator is running at maximum efficiency.
Check Your Oil Levels – Always check your backup generator oil levels to make sure they are not too low. If the level is below “ADD” on the engine oil dipstick, then add engine oil until it reaches that point.
Regular Cleaning – Regularly clean your generator by taking off any debris and making sure all parts of your generator are free from corrosion or dust build-up.
Battery Inspection – Check the battery if there is any leak, corrosion, or bulging. If any of these apply, replace the battery with a new one and wipe down all metal surfaces to remove acid deposits.
Cover Your Generator – Always cover your generator when it is not in use, whether that be during an outage for inclement weather conditions such as rainstorms or winter snowstorms. This will help protect the generator for lasting long.

I’m James Martin and I live in Arizona. I work as a civil engineer and love the great outdoors. I enjoy being off the grid and survivalist culture fascinates me. Over the years, I’ve used many portable generators as a backup power source for emergencies or the main power source for mobile living and other temporary sounds/light installations. This website was started to share my honest inverter generator reviews and I hope this will help you to find the best portable generator for your needs. Start with the list of my favorite generators!