How Long Does Generac Last During Outages?

How Long Does Generac Last During Outages?

Ian Mutuli
Updated on
Ian Mutuli

Ian Mutuli

Founder and Managing Editor of Archute. He is also a graduate architect from The University of Nairobi, Kenya.
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No one can dispute the pivotal role of generators as sources of power. Be it during outages or in off-grid areas, these power equipment are indeed reliable. In line with reliable generators, we can't overemphasize the top quality of Generac generators. Accordingly, one would be tempted to ask, how long does Generac last?

In this article, we aim to unpack this question by understanding the key features that support the running of a Generac generator. Nonetheless, the 'lasting' or continuous running, in this case, should be taken into the context of an emergency. Eventually, you will know if your select Generac generator will help you outlast outages until power is restored.

Factors that Determine How Long a Generac Generator Lasts

Understanding how long a backup generator will run continuously is pegged on certain key factors. Knowing these factors will effectively help you get the right unit for your power needs. Therefore, here are the factors to consider in understanding how long will a backup generator run continuously.

1. Type of Generator

Portable Generators

This first type of Generac generator is made for easy movement depending on where power is needed. Due to their hassle-free movement, these models are ideal for emergencies and recreation. However, during emergencies, they are best applied as target generators as you only use them to run the essential appliances, making them limited in functionality. Soon, you'll find out why they are limited.

Additionally, the Generac portable Generac units are relatively cheap and smaller. However, you can also find expensive models within the portable class, with more power justifying their price tag. This is to say, the lower the price, the shorter time a portable Generac generator will run continuously, and vice versa is true.

Normally, portable Generac generators would give you 10 hours of stable and continuous running on a full tank and 50% load. Moreover, you can get up to 30 hours of continuous running with more powerful portable models under the same conditions of 50% load and a full tank. Therefore, the more expensive a portable Generac generator is, the longer it can last you compared to the more affordable models.

Even as you bank on higher-end models for more run time, portable generators still don't beat the whole-home generators. Ideally, you can't run your portable Generac generator continuously for longer as suggested since they might overload and overheat. As a result, pushing the portable models to the limit exposes them to risks of breaking down. As such, you can't load many appliances onto a portable Generac model to increase the generator's lifespan.

Standby Generators

On the other hand, standby generators are meant to supply power to an entire house. Therefore, Generac standby generator models effectively run a premise as usual, even during an emergency. Additionally, these units are meant for permanent placement and thus the ideal power backups. Besides homesteads, these generators are used in hospitals, learning institutions and businesses for zero power inconveniences.

These generators come with larger fuel tank sizes and more power output in line with their functions. As a result, they're bound to run continuously for more hours than the portable models. Ideally, a Generac standby generator can provide 90 hours (over 3 days) of continuous run time for a better picture of the same.

Moreover, it's easy to say that the prices of these generators are indicative of their functionality. Therefore, these models are more expensive than their portable counterparts. Even so, Generac has created an affordability scale within this type with a variety of standby generators for different capacities and uses. That said, a hospital backup generator will be more expensive and powerful than the Generac standby generator meant for domestic use.

2. Type of Fuel

Furthermore, the run time of a Generac generator, whether portable or standby, depends on the type of fuel it consumes. Fortunately, Generac generators can be configured to run on different kinds of fuel. As such, your Generac generator will use fuel available in your location. Without much ado, here are the main types of fuel to choose from:

  • Diesel
  • Natural gas
  • Liquid propane


Generac diesel generators are the most robust in terms of power output. However, run time is debatable other fuel tanks don't apply the principle of a full tank. Nonetheless, the run time of a standby diesel generator is better than that of a portable diesel generator. Generally, diesel is a more reliable fuel since its popular and available in almost every location.

In addition, you can buy extended tanks for diesel Generac generators to enable storage of reserve fuel for increased run time. As such, the more high-end models will provide more run time, similar to the standby units as compared to the portable units. Indeed, diesel as a fuel guarantees more run time depending on your Generac model, but the cost incurred might not excite you. Overall, diesel is a reliable fuel for generators in most locations.

Natural Gas

For homes connected to a natural gas line, you can comfortably go for a natural gas Generac generator. The advantage of a natural gas line is that your generator will run continuously until its shut off. However, the more natural gas your Generac generator consumes, the higher the utility bills you will incur. Nevertheless, natural gas costs are lower than those of diesel fuel.

Above all, Generac natural gas generators provide exceptional run times as long as your natural gas supply is constant and reliable. Fortunately, most Generac models, particularly standby units, consume natural gas. The standby models suit this fuel type since they aren't moved once installed. However, the installation process will cost you extra bucks, but you will enjoy the run time eventually.

Liquid Propane

The least in the run time order is liquid propane, but it will still help you during emergencies. In most cases, a Generac generator that runs on natural gas can also consume liquid propane without many reconfigurations. Nonetheless, compared to the other fuel types, the run time of liquid propane is limited to the propane cylinder capacity. As such, the larger the liquid propane cylinder you use, the more run time you obtain.

Additionally, you can find either standby or portable generators that run on liquid propane. As you opt for liquid propane, remember that more power demands cause your propane supply to run out quickly. But not to worry, your backup power will be restored as soon as you renew your propane supply.

Compared to natural gas, liquid propane can be stored, making it viable for remote locations or areas without natural gas. Also, liquid propane is more efficient than natural gas due to its lower consumption rate. Additionally, liquid propane provides more power than natural gas, but that is not to say it can outlast natural gas during continuous running. Overall, liquid propane runs as much as the fuel tank will allow you.

3. Load and Running Watts

Load is the power quantity supplied to a generator for its demands. On the other hand, running watts is the power produced by a generator. Based on these two aspects, it's important to consider the demands of the essential appliances when answering how long can a Generac last.

Particularly, prioritizing essential appliances mostly matters when using portable generators, which often have lower running watts and load. Additionally, portable generators can only handle a fraction of the items since they're prone to overheating when overloaded. On the other hand, when it comes to a Generac standby generator, you can easily power more appliances due to their more load.

Even when using standby generators, it's important to completely assess your home power needs. An assessment will help you invest in a generator with the right power load and running watts to suit your power needs. Not to worry, you can assess by adding the power consumption rates of your appliances to get a rough figure of the required load.

Additional Tips and Tricks for Running your Generac Continuously

1. Have a Consistent and Reliable Fuel Source

Based on the analysis of fuel, your Generac's run time highly depends on the availability of the fuel you choose. Even when your Generac is new, you can't achieve half the expected run time without fuel. Therefore, if your fuel can be stored, strive to have reserves to maximize the run times. After acquiring your select Generac generator, ensure you understand its fuel needs for reliability.

Despite having the best run times, any Generac generator should be used as a power backup rather than the primary power source. Regardless of the fuel you use, day-to-day use of a generator can be expensive. Therefore, connection to a grid line is ultimately the cheapest option, and a generator is for emergency and occasional leisure.

2. Proper Maintenance

Similar to any engine, Generac generators require regular maintenance and repairs. Breaking down parts can subsequently affect the run time of your Generac. Additionally, changing the oil, oil filter, and fuel filter (for diesel Generacs) is paramount for proper functioning.

Regularly replace the engine oil since it's important in lubricating and cooling the engine. Failure to change the oil will cause overheating and increased wear and tear. In addition, your Generac might develop mechanical complications in the extreme, hampering its run time. Manufacturers often recommend changing oil and filters after 200 hours of running, but you check your Generac for oil maintenance details.

Changing the Generator's Oil

Image Credit:

Additional Generac Maintenance Tips

1. Inspecting the Battery

Ensure battery terminals are clean for efficient power transmissions. Additionally, the terminals should be tight to avoid any power losses. Overall, a battery is important while starting your Generac and other control panel functions.

2. Inspect the Mounting Surface

Always ensure the mounting surface for your Generac is clean. This will prevent any contamination that might hamper optimal run times. Additionally, the mounting surface should be flat for stability. Any unwanted generator movements during running might cause disconnections, thus reducing the usable run time.

3. Check the Intake and Exhaust Airways

A generator requires air to burn the fuel during combustion, and after combustion, fumes are emitted. Therefore, the Generac louvers shouldn't be clogged. Insufficient air intake may lower the run time, similar to the clogging up of the exhaust louver.

3. Never Run a Generator in Enclosed Spaces

Lastly, never run your Generac in enclosed spaces. Ideally, carbon fumes are produced when a generator is running. Therefore, if a running generator is placed in an enclosed space, it might suffer carbon monoxide poisoning. In the end, such poisoning might lead to reduced run times.


Generally, Generac generators have impressive run times. Different Generac generators will provide different run times, factoring in the mentioned determinants. If cost isn't a factor, having a stable and continuous supply of fuel will ensure you optimize the run time of your Generac.

Nonetheless, avoid overworking your Generac for increased longevity. Also, ensure you do proper maintenance to your generator for consistent running over time. In the end, you should be able to match the power capacity of your Generac to your power needs for ideal run times.

Image Credit:

Ian Mutuli

About the author

Ian Mutuli

Founder and Managing Editor of Archute. He is also a graduate architect from The University of Nairobi, Kenya.
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