How Long Does A Generator Last? A Quick Guide

Generators are fantastic equipment with a wide variety of applications, from providing emergency electricity in the event of a blackout or storm to lighting up a camping trip or outdoor party. While you won’t need to run a generator for long most of the time, extended blackouts (especially during harsh weather) are an exception.

It thus begs the question, how long does a generator last before problems arise?

Generator Being Set Up After A Hurricane

You raise a valid point. There are several variables to consider, but the largest ones are generator size, brand, and fuel type. Let’s take a look at some of the more typical cases.

Under normal conditions, a generator can be run continuously for 12-18 hours as long as safety precautions are followed.

Generator Types

Standby generators and portable generators are the two most common kinds. The lights can be kept on with the help of these generators in the event of a blackout, but not all of them can be left on for days on end.

How long Can You Keep a Portable Gasoline Generator Going?

A gasoline-powered portable generator must be shut down periodically rather than used continually.

Various Portable Gasoline Generators

When operating a gas-powered generator, never refuel while the unit is running. Although adding gas may seem harmless, it poses a significant fire risk.

A little spark from a spill or even fumes released by the operating generator could soon spread to the gasoline tank in the generator or the tank you are using to replenish. Dangerous!

We recommend waiting 5-10 minutes after refueling the generator before starting it up again.

You should not exceed the recommended operating time when using a gasoline generator. Depending on the model, fuel economy, and electricity needed, a gas generator’s run time could be anywhere from six to twelve hours. Keep in mind that some possibilities have more time invested than others.

The Westinghouse WGen3600v has a relatively long operating time (18 hours) per tank, placing it among our top picks.

How long Can You Keep a Portable Generator Running on Propane?

Portable Generator Running On Propane

If your backup power source is a propane-fueled generator, you have complete management over the propane supply. That provides several alternatives for maintaining a steady fuel supply for your generator.

You can quickly increase your propane generator’s runtime by connecting two propane tanks to a single gas line using a stopcock valve or changeover regulator. In this approach, only one of the propane tanks needs to have its valve opened. Simply turning the stopcock valve allows you to convert between propane tanks.

In this case, a new propane tank can be installed in place of the old one, ensuring there is never a fuel shortage.

Assuming you have an infinite supply of propane, how long does a generator last?

It is recommended that you service your portable generator every 100 hours; however, this is not always the case. Instead, the amount of oil in your generator’s engine will be your primary restriction. Most contemporary generators will shut down automatically when the oil level drops below a certain threshold (usually between 150 and 200 hours of use) to prevent damage to the engine.

When operating your generator for an extended period of time, remember that heat accumulation is also a significant factor. Using a generator continuously for more than a day runs the risk of overheating the engine, which could lead to irreparable damage. However, after 12 to 24 hours of use, the generator may only build up a small amount of extra heat.

To keep the generator’s engine cool in hot weather, you may try running the fan and filling it with ice. Keep in mind that operating the generator at greater wattages will cause it to produce more heat.

Maintaining your generator properly could allow you to keep it going for as long as 150-200 hours on a single tank of propane.

How Long Do Standby Generators Last?

While it is feasible to maintain constant power for extended periods, doing so with a portable generator is not ideal. A standby generator is the most reliable method of maintaining continuous power.

Standby Generator Being Installed By Technicians

These are constructed to last for a long time. The engines of standby generators are fuel-efficient and built to operate continuously for extended periods. They can also be hooked up to natural gas lines or large propane tanks (up to a thousand gallons).

Always remember that there is a safe upper limit for your standby generator. Two to three weeks of continuous electricity generation is common under these conditions.

You can utilize your standby generator for longer than is suggested. However, doing so could destroy your home’s electrical wiring and appliances, as well as your generator.


There are plenty of situations where a portable generator might be essential. It can assist you in creating power so that you can use your tools even when you’re not near an outlet. And it can help keep your home or food stand running even when the power is down. Its fuel capacity is the primary constraint on its operational time. While there are longer-lasting generators on the market, most can power a home for anywhere from 8 to 12 hours.

How long does a generator last is also typically determined by its runtime? Commonly available portable generators have a lifespan runtime of 10,000-21,000 hours at 50% load.

Thus, the generator can serve you for more than a decade or two if you use it exclusively when the electricity goes out. However, if you regularly use your generator, you should plan on replacing it within a few years. Either way, before you buy a new generator, you should run through this checklist to rule out the most likely causes of its inability to kick on.


Is it possible to run a generator overnight?

Yes, if you follow generator safety procedures. We originally advocated just running a generator for 12-18 hours at a time. Always utilize a carbon monoxide detector and avoid back feeding.

How long does a generator last?

A portable gasoline generator can run for eight hours on a full tank. 12-18 hours is typical. Mechanical issues limit large propane tanks (typically engine oil). Propane generators should last 5 to 8 days. A gas-powered generator can run for 500 hours or 20–21 days.

How frequently should a generator be replaced?

The age of a generator is the most telling factor in determining whether or not it needs to be replaced. If it’s older than ten years, it probably has some damage. On average, the lifespan of a standby generator is between 10,000 and 30,000 hours.

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Skyler is an outdoor adventurist and avid RV-Fan. He loves to explore the world and all its beauty, but he's just as happy relaxing at home with his family. His favorite pastime is taking weekend trips in his RV with his wife and kids, where they can get away from it all and enjoy nature. He’s also a self-proclaimed expert on all things portable generators and can often be found reviewing the latest models on our website.

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