Generac GP5500 Review

Powerful, long-lasting and $1,000 cheaper than some of its competitors, the Generac GP5500 is versatile enough for home and work use, and boasts an impressive spec sheet for its size.

Generac GP5500 (5939) review
(Image: © Amazon)

Top Ten Reviews Verdict

The Generac GP5500 (5939) is a powerful portable generator that punches well above its weight – particularly when you factor in the price. Great for power outages at home, it’s also good for DIY and off-the-grid situations like tailgating – but it's a little on the noisy side for camping.


  • +

    Very powerful

  • +

    Easy to use

  • +

    Exceptional value for money


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    Louder than some

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    Control panel is basic

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    Marginally heavier than some

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We've researched the latest portable generators, asked the experts, and sifted through thousands of specs, features and user reviews to find the best portable generators around. Here's everything you need to know about the Generac GP5500.

Generac GP5500: What is it?

Generac GP5500 (5939) review

(Image credit: Amazon)

The Generac GP5500 (5939) is a popular, powerful portable generator. Made by Generac – a go-to brand for affordable home generators in the United States – it’s one of a series of models in the GP range. In this Generac GP5500 review, we’re looking at the 5939 version.

The Generac GP5500 (5939) comes with a gasoline-powered 389cc OHV engine, long-lasting fuel tank and heavy-duty steel frame. It produces an impressive 5,500 watts, with a high 6,875 watt starting power. That’s enough juice to power an RV (recreational vehicle) or provide backup power to your home for several hours.

It can run most household appliances, including more demanding items like power tools, air conditioners and refrigerators, alongside small devices like computers, heaters and lights. It’s also a good off-grid electricity provider for construction sites, and recreational activities. 

Generac GP5500: Price

The Generac GP5500 portable generator costs $729, if you buy it directly from Generac. However, if you buy it from a retailer like Walmart, Home Depot or Amazon, you can often find it on sale for under $700.

One of the big reasons why the Generac GP5500 is our top choice of portable generator is its price. There are more powerful options available – some with more features; some more portable – but you’ll likely be paying over $2,000 for the privilege. Priced well below $1,000, the power and utility you get from the Generac GP5500 is exceptionally good value.

Generac GP5500: Features

As you might expect, the Generac GP5500 sacrifices some advanced features to achieve its more affordable price. Its headline feature, though, is the impressive amount of power it can generate.

Generac GP5500 specs

Running Watts: 5500
Surge Wattage: 6875
Engine type: OHV
Fuel: Gasoline
Tank capacity: 7.2 Gallons
Run time: 10 Hours at 1/2 load
Weight: 171 lbs
CA (CARB) Compliant: No
Warranty: 2 years

That's thanks to the 389cc OHV engine, which is great for several additional reasons. Chief among them is that it places the valves above the cylinder head instead of the flathead engine – like those found in a conventional piston engine. This engineering improvement means that the engine is smaller, less complex and longer lasting. The engine also features splash lubrication, which again prolongs the overall life of the generator.

One of the most important aspects of any portable generator is what you can hook up to it. There are no DC outlets here, but you do get four common household outlets (120 volts, 20 amp) and a single industrial locking outlet (120 volts, 30 amp) for appliances, which will be plenty for most people’s needs. All five outlets are covered, to protect them, and have their own circuit breaker.

Generac GP5500 (5939) review

(Image credit: Amazon)

The control panel on this model is limited compared to more expensive options, but it’s very user friendly. Aside from the outlets, there’s only an hour meter that indicates when the machine is ready for routine maintenance. The Generac GP5500 does have automatic low-oil shutdown functionality too, to reduce the risk of engine damage, but there isn’t an indicator light for this.

Also – and surprisingly, given its size – the Generac GP5500 uses a recoil starter. This isn’t difficult to use, but we’d have preferred to see an electric push start or remote start, which would be more convenient.

Generac GP5500: Design

Generac GP5500 (5939) review

(Image credit: Amazon)

The Generac GP5500 is compact, sturdy and durable. It has a strong, reinforced steel frame, making it resilient to damage and well-suited for heavy-duty use.

Bear in mind that it’s fairly heavy, weighing in at 170 pounds. That’s a bit heavier than the category average of 132 pounds – and you will find models that are easier to transport, like the Champion Power 75537i. However, it remains fairly portable thanks to its 9.5-inch wheels (it uses never-flat tires, so you can take it on the road in environments where regular tires risk being punctured) and a foldable handle.

Generac GP5500: Performance

Compared to other portable generators of its size and weight, the Generac GP5500 has a lot of power. Run time is also good: the 7.2-gallon gasoline fuel tank provides power for up to 10 hours on a 50 per cent load, making it one of the longest-lasting portable generators that we looked at. Of course, if you decide to buy a higher-powered, more expensive model from the GP line, you’ll get a longer run time. But for a generator of this size, 10 hours is excellent.

In addition, the 6,875 watt starting power is particularly impressive for a generator of this size, making the Generac GP5500 much less likely to overload with the surge start-up requirements of electrical appliances.

It’s a little noisy, though. The Generac GP5500Bear runs at around 71 decibels, which makes it one of the louder portable generators we evaluated – the loudest was only two decibels higher. You’ll still able to hear conversations over it, especially if you’re not standing too close, but it probably isn’t the best option to take camping, for example.

Generac GP5500: User Reviews

At Walmart, the Generac GP5500 (5939) averages 4.7 out of 5 stars, over 750 user reviews. The Home Depot scores it 4.7 out of 5, from over 1,000 reviews; while at Amazon, users have rated it 3.7 out of 5, over 97 reviews. 

The vast majority of users report that it’s very easy to set up, and delivers an outstanding performance. Many found that it starts easily, running after only one pull. One user, in particular, used it as his only source of power at home for five months: he said he ran it daily for up to 16 hours with no problems. However, a very small number of users (less than 10) reported that their generator broke down after less than one year in use. 

Of the limited drawbacks to the Generac GP5500, a regular comment is it’s noisier than expected and the muffler isn’t particularly effective at reducing the sound. Some users report that it’s surprisingly quiet, though, so bear in mind that this feedback is subjective. 

Finally, a few users have pointed out that the engine can have problems running on gasoline purchased from a standard gasoline pump, which may be up to 15% ethanol. You’ll need low-ethanol fuel for optimal performance. 

Should you buy the Generac GP5500?

Generac GP5500 (5939) review

(Image credit: Amazon)

Yes. If you’re looking for a portable generator that just works, with no fuss, the Generac GP5500 should be an excellent choice for homes, recreational use, and small-to-medium businesses. It’s a little loud, but it’s more powerful than other generators of its size, very easy to use, runs for a long time, and it’s easy to move around as well. 

Plus, it’s significantly cheaper than many other similarly powered models, which makes it excellent value for money. We think the Generac GP5500 is an outstanding portable generator.

Alternatives to the Generac GP5500

Not convinced that the Generac GP5500 is right for you? You’ll find plenty more options in our best portable generator guide, where we've selected a range of models that excel in different situations, for all budgets. However, if you're in a hurry, here are our three top alternatives to the Generac GP5500.

J.D. Chadwick

J.D. Chadwick started writing articles for Top Ten Reviews 2008, and left the team in 2018 after filling the role of Multimedia Editor. A keen video creator, and expert in software, he was one of the most prolific members of the old TTR team, authoring articles on things like antivirus software, video editing apps, and more.