How Long Can a Whole House Generator Run Continuously?

At its best, a whole-house generator would run up to 3000 hours continuously when powering a medium-sized house. Still, it is not recommended to run the generator for more than 500 hours continuously.

Extended power outages can be frustrating, so choosing the best whole-house generator that will last a long time is very important. There are many things to consider when determining the best generator with a longer runtime. In this article, you will help you understand how long a whole-house generator can run continuously when you incorporate these factors.

Factors that Affect Whole House Generator Run Time

Whole house generators are designed to provide power supply in your home when there is a power shortage. This is why they are designed to automatically go on when they detect a power interruption. Still, various factors determine how long your home generator runs.

Type of Fuel

Type of fuel / Laricina energy

A generator is expected to run continuously as long as fuel continues flowing into its tanks. Natural gas and propane are considered the most preferred sources of energy. This is because they are clean and safe for the environment. They also do not go stale after a while. Natural gas produces an infinite fuel supply that can run continuously for weeks. This is only interrupted when its pipes, which run underground, are interfered with by power lines and falling trees.

Liquid propane is the next best choice. Typically, they are usually stored in large tanks of between 250 and 1000 gallons. In a day, a whole-house generator will, on average, burn 36 gallons, meaning the generator can run for a whole week.

Other generators use diesel or gasoline, which are also good energy sources. However, they tend to go bad over time since they cannot stay in a tank for a long while. They become contaminated. Remember that whole house generators are only backups, and you may not use them often. So you will continuously have to get rid of the old fuel in the tank and buy another tank full. This is quite expensive. The diesel and gasoline ensure a whole house generator runs for a full day or up to 72 hours if it is a large diesel-filled tank size.

Fuel Source Reason to use it Reason not to use it
Natural gas Fuel is infinite and runs continuously as long as there is no interruption in the supply. It can be interrupted by falling trees or other small animals destroying the underground pipes.
Propane Just like natural gas, this is a clean-burning fuel and environmentally friendly. It is a fast burner; hence you will run through it very quickly
Gasoline or diesel It is simple to operate and does not demand extreme levels of maintenance This source of energy deteriorates and becomes contaminated when it sits in a tank for long, yet you won’t be using your generator often

Oil Replacement

Additionally, it is essential to oil your generator’s parts often just to lubricate them. By so doing, you prevent friction on the engine’s moving parts and also cool your generator to prevent overheating. In most whole-house generators, oil breaks down and needs a replacement after 50 hours of running continuously. This is why you should be keen on when your generator needs an oil change.

According to research, the best whole-house generators have engines operating at 1800RPM. These consume less oil, run cooler, and are the best option for extended power outages. They are more expensive but more efficient than the 3600RPM. The 3600RPM is more efficient in short-lived power outages.


In summary, the runtime of whole-house generators is determined by the fuel source and the frequency of oil replacement. The best fuel source is natural gas, which will allow your whole house generator to run for weeks before finally going off. Also, maintain your machine and let it get tested at least once each year to ensure it runs properly.


What is a standby generator?

This is also a whole-house generator. It is a stationary generator that automatically goes on when a power interruption is detected, and it can run continuously for hours until electricity finally returns.

Can I fuel my whole house generator as it runs?

Absolutely not! You cannot fuel your whole house generator while it runs. This is very dangerous, and the generator might burn you. Remember that a running whole-house generator also emits heat. So it can also cause explosive sparks when they get in contact with the fuel. So wait for your generator to run out, then fill it up again.

  • Nichole Hutt

    Hi, I'm Nichole! 👋
    I always felt close to nature during my childhood. Preferring to spend my time alone playing with backyard animals at my family farm. 🐷
    In 1997, I attained my electrical engineering degree at the Oregon Institute Of Technology, graduating top of my class. Several years later, I qualified for my M.S. in Renewable Energy Engineering, also at OIT. 🎓

    Combining my love for nature and passion for engineering, I have worked for solar panel manufacturer's in my state, most notably as a PV solar engineer for Zamp Solar.

    I founded RenewableSystems to share my knowledge and expertise in the renewable energy field and help save this beautiful little planet of ours. ☀️🌎

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