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Generac GP2500i Review | GP Series Inverter

Generac GP2500i

The Generac GP2500i is a compact powerhouse, who’s small size hides a robust product. While not all perfect, the pros of this model greatly outweigh its flaws. For full specs, pros, cons, and other models in the same GP series, read our Generac GP2500i review below.

It’s easy to start, fuel-efficient, and it makes an excellent option for tailgaters, campers, and those who want to work when they want, where they want. Its lightweight design and convenient USB ports make this an easily portable power option for a short weekend trip or a backyard barbeque. The Generac GP2500i also has some significant improvements over its predecessor, the Generac GP2200i. It offers more power, better fuel efficiency, and easier maintenance – all that with almost no change in the weight or cost.

Generac GP2500i Specification

Wattage: 2500 watts starting – 2200 watts running
Fuel type: Gasoline
Fuel tank capacity: 1.0 gallons
Run-Time: 8 hrs @ 25% load
Noise-Level: 60 dBA @ 25% load
Weight: 48 pounds
Dimensions (LxWxH): 19.7 x 11.4 x 17.9 inches

Starting method: Recoil pull start
Engine: 4-stroke engine
Engine displacement: 98 cc
Material: Multi
Receptacles: (2) 120V AC- (1) 12V DC – (2) 5V USB
Warranty: 3-year warranty
Certificates: EPA – CSA – CARB

Power Capabilities

The Generac GP2500i inverter generator is powered by a 98cc, single-cylinder, four-stroke OHV engine. It offers a starting wattage of 2500 and a running wattage of 2200. With a peak amperage of 20.8 and a running amperage of 18.3, you can comfortably run or charge several small devices or a few larger ones. While it won’t power the AC, microwave, TV, and refrigerator all at once, it runs multiple small appliances simultaneously with no problem. Supported by True Power technology, this top inverter generator provides stable power for sensitive electronic equipment.


The Generac GP2500i only has a one-gallon fuel tank, which is good, but not great. Still, with a run time of 4.5 hours at half load and 8 hours at quarter load, fuel efficiency is relatively high with this model. With this amount of run time, you generally won’t have to wake up in the night to refill the tank to run an AC or heating unit. A full night of sleep at a comfortable temperature makes this a pro in our book! The fuel consumption is about 0.13 gallons per hour.

Noise Level

The GP2500i is in the middle of the road when it comes to the noise level. At lower loads, you can expect the noise level to be approximately 60dB. For a quiet portable generator, the enclosed body design significantly reduces the noise level, so the Generac GP2500i is a good middle of the road option between price and noise level. It also has an economy mode switch that will give it less power for your devices but will reduce the noise level even further.

Generac GP2500i control panel

Control Panel

The control panel of the Generac GP2500i generator lacks a data center. While having a data center does nothing as far as performance goes, it certainly makes it easier to detect how things are running and if there is anything that needs attention. Even a simple fuel gauge would keep this from being a con on our list, but even this basic function is missing.

However, it does have indicator lights. These lights show when oil is low, when the generator is overloaded, and when it’s ready to use. While these lights are helpful, it really is the bare minimum when it comes to a data center. Future models of this generator would benefit from a more advanced data center with a digital display.

One great thing about the control panel is that it comes equipped with USB ports. Forgot the adapter plug for your cell phone charger? Not a problem! With ports to give power to and charge USB devices, all you need is the cords – no wall adaptors or hunting for outlets required. It also has dual 120V AC household outlets and one 12V DC receptacle.

Functionality and Design

Generac GP2500i functions

The functionality of the Generac GP2500i is very user friendly. Even those with low mobility or little upper body strength should have no problem getting this generator to start. A second pull is rarely needed, and it starts right away. While it won’t provide full power for a big Class A motorhome, the Generac GP2500i runs multiple small appliances simultaneously with no problem.

However, the dial on the Generac GP2500i has to be turned to the ‘choke’ option when attempting to start it. Then, once started, the dial needs to be moved over to ‘run’. This isn’t a huge concern, but it can be a little confusing, as many generators will start just fine when turned to ‘run’. This rule applies even when the generator has been recently used and is considered ‘warm’. It’s a small thing, but if this is your first generator, it can cause frustration even after carefully reading the instructions.

The design also leaves something to be desired due to its lack of wheels. While 48 pounds won’t pose an issue for some users to easily move around, the lack of wheels can be a massive issue for people with mobility issues or little upper body strength. The addition of wheels and a retractable handle would be a good change for future models in this line.

Additional Features

The Generac GP2500i inverter generator is parallel capable. Meaning, you can connect it to another identical unit using a paralleling kit and get twice the power output. This will allow you to power more machines or larger appliances, such as a larger AC unit.

The low oil shutoff is an absolute pro in the fact that it prevents damage to the generator due to running without oil. It also uses relatively little oil compared to some other models. However, even with the low oil use, the low oil shutoff triggers if the oil is barely under the full line.

This caused some confusion, as the generator would just seem to occasionally stop at random or not start when the dipstick read the oil was half full. Because this is a safety measure to prevent expensive damage, the mild inconvenience of having to top off the oil occasionally makes this fall into ‘neutral’ territory.

parallel feature

Generac GP 2500i Review: Maintenance

Oil changes are the only significant maintenance needed for the Generac GP2500i. The only way to change the oil is to empty the old oil through the fill hole. While the generator is lightweight, as far as portable generators go, it’s a bit awkward to hoist forty-eight pounds or tip it in a way for all the old oil to drip out. Additionally, due to the odd angle, emptying the old oil can be a messy affair. Be sure to use a large catch pan and perform oil changes away from anything you want to keep oil-free.

The user manual states that the oil in the Generac GP2500i needs to be changed every 100 hours. Compared to the GP2200i which requires an oil change every 50 hours, it significantly improves. If you’re a weekend warrior that needs a generator once every few months, this isn’t much of an issue. Change the oil before a weekend trip, and everything will be fine. As long as regular maintenance like oil changes, are performed, you’ll have no issues in performance.


  • Clean energy for delicate electronics
  • Works great in all weather 
  • Low noise level
  • Fuel efficiency
  • Parallel operation ready
  • A 3-year warranty
  • EPA, CSA, and CARB approved


  • Changing the oil is not easy
  • There is no data center
  • No fuel gauge
  • No electric start

Other Models in the Generac GP Series

Generac GP series

The line of the Generac GP series has other popular inverter type generator models, they include;

  • GP1200i 76711 with 1200 starting watts and 1000 running watts.
  • GP2200i 7117 with 2200 starting watts and 1700 running watts.
  • GP2500i 8250 with 2500 starting watts and 2200 running watts.
  • GP3000i 7129 with 3000 starting watts and 2300 running watts.
  • GP3500iO 7128 with 3500 starting watts and 3000 running watts. It’s a ready RV generator, and it’s different from the other models with its open-frame design.

Check the our detailed review of the Generac GP5500.

What's Inside the Box
  • Battery Charging Cable
  • Oil
  • Funnel
  • Tool Kit
  • Generac GP2500i Review – Conclusion

    In conclusion, the Generac GP2500i inverter generator is a great overall option for a portable generator. It’s lightweight, quiet, fuel-efficient, and has the capacity to run in all weather for many years. This generator by itself would be an excellent option for weekend trips and tailgating parties, but if you have a big rig RV or need to power multiple large devices at once, running two of these generators together is required. Not to mention, it has some significant improvements compared to the GP2200i.

    Despite some awkwardness surrounding oil usage and changes and the lack of a data center, this generator does its job and does it well. We hope you have found our Generac GP2500i review helpful and useful in making a decision on which portable generator is best for you.

    Generac GP2500i Review
    • 8/10
      PERFORMANCE - 8/10
    • 7.7/10
      ACCESSIBILITY - 7.7/10
    • 7.6/10
      DURABILITY - 7.6/10
    • 7.5/10
      NOISE LEVEL - 7.5/10
    • 8.2/10
      VALUE - 8.2/10


    The Generac GP2500i is a recent release from the GP Series inverter generator line. It comes with some significant improvements over its predecessor, including more power, better fuel efficiency, and ease of maintenance – all with almost no change in weight or cost.

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