5 Largest Portable Generators On The Market

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Discover the largest portable generators on the market so you can fulfill your biggest power needs in a relatively mobile way.

  1. Westinghouse wGen20000 – Largest portable generator (28000 peak watts, <5% THD)
  2. Powerhorse 27000 (27000 peak watts, <5% THD)
  3. Generac GP17500E (26250 peak watts, high THD)
  4. Westinghouse wGen12000DF – Largest portable dual fuel generator (15000 peak watts, <5% THD)
  5. AIVOLT 10000 – Largest portable inverter generator (10000 peak watts, dual fuel)
  6. Bonus: Westinghouse wGen9500 – Best large portable generator (12500 peak watts, high THD)
Brand ModelPower
Capacity
Run
Time
Quiet
Operation
THDReliability
Reputation
Fuel
Efficiency
Ease
Of Use
PortabilityPrice
Category
Current
Price
Westinghouse wGen20000108.56<5%888.52.5$$$$Check Price
Powerhorse 27000107?<5%8.5683$$$$Check Price
Generac GP17500E9.58?High
THD
7.57.584$$$$Check Price
Westinghouse wGen12000DF7.58.56<5%8.588.54.5$$$Check Price
AIVOLT 100006.598.5<3%7.598.55$$Check Price
Westinghouse wGen9500776<23%97.58.56$Check Price
Largest portable generators performance on a score of 10 in important categories*

*Compared to similar generators and sometimes based on customer input

1. Westinghouse wGen20000

The Westinghouse wGen20000 is the largest portable generator on the market with an impressive 28000 starting watts and 20000 running watts.

Westinghouse wGen20000

That being said, even if you need this much power, it is likely smarter to get two smaller models since you would have to use multiple outlets anyway.

The main reason for this is the above-average rate of technical issues customers have with the Westinghouse wGen20000.

Since you likely don’t want to take the 540 pounds (245 kg) to the store or risk a big investment like this, you likely want to go for smaller portable generators anyway.

Pros

  • Westinghouse wGen20000 offers 28000 starting watts, 20000 running watts, 50 amps, and 240 volts
  • Nice run time of 11 hours at 50% load
  • Less than 5% THD
  • Has electric and remote start
  • Four GFCI outlets
  • Version with CO sensor available too
  • 3 years limited residential and 1 year limited commercial warranties

Cons

  • Heavy weight of 540 lb (245 kg)
  • Noise levels of 74 dBA are somewhat loud
  • Decent number of technical issues

At the same time, it is worth noting that the Westinghouse wGen20000 also has positive points.

For example, the electric and remote start make operating the Westinghouse wGen20000 relatively convenient.

Additionally, it may come as a surprise but this large portable generator actually has a low THD rating.

In simpler words, this means the Westinghouse wGen20000 should be able to power sensitive electronics like a microwave, refrigerator, or AC safely.

So the Westinghouse wGen20000 is still an alright portable generator but there are enough reasons to consider other options.

Brand ModelPower
Capacity
Run
Time
Quiet
Operation
THDReliability
Reputation
Fuel
Efficiency
Ease
Of Use
PortabilityPrice
Category
Current
Price
Westinghouse wGen20000108.56<5%888.52.5$$$$Check Price
Westinghouse wGen20000 performance on a score of 10 compared to similar alternatives

2. Powerhorse 27000

The Powerhorse 27000 is only slightly smaller than the Westinghouse wGen20000 but more promising in terms of reliability.

Additionally, with 27000 starting watts and 18000 running watts, this portable generator should still be big enough for your power needs.

One thing you do want to keep in mind is that there are not that many Powerhorse 27000 customers yet.

Powerhorse tends to be a good generator brand but it is still possible the quality at a bigger scale is suboptimal.

Pros

  • Powerhorse 27000 offers 27000 starting watts, 18000 running watts, 50 amps, and 240 volts
  • Run time of 8 hours at 50% load
  • Less than 5% THD
  • Has electric start
  • 24 months parts and labor warranty
  • Customers are happy so far

Cons

  • Heavy weight of 510 lb (231.33 kg)
  • No noise level rating
  • Not that many customers yet

Additionally, the weight of 510 lb (231.33 kg) will take some effort to move around.

The main thing that positively stands out in the Powerhorse 27000 is its relatively low THD of less than 5%.

This makes it so you should be able to run sensitive electronics with this large portable generator.

Besides that, the Powerhorse 27000 is somewhat average in other areas.

This is not necessarily bad considering everything you get for the reasonably sized investment.

Brand ModelPower
Capacity
Run
Time
Quiet
Operation
THDReliability
Reputation
Fuel
Efficiency
Ease
Of Use
PortabilityPrice
Category
Current
Price
Powerhorse 27000107?<5%8.5683$$$$Check Price
Powerhorse 27000 performance on a score of 10 compared to similar alternatives

3. Generac GP17500E

The Generac GP17500E definitely deserves a spot on the list of largest portable generators with its 26250 starting watts and 17500 running watts.

At the same time, you will likely prefer investing in another model with the rate of technical issues customers have with the Generac GP17500E.

Additionally, the Generac GP17500E produces high THD power.

This means you need your own way to “clean up” the energy if you want to run sensitive electronics safely.

If the Generac GP17500E would be outstanding in other areas, you could potentially risk it.

Pros

  • Generac GP17500E offers 26250 starting watts, 17500 running watts, 50 amps, and 240 volts
  • Nice run time of 10 hours at 50% load
  • Has electric start
  • Two GFCI outlets
  • 2 years limited residential and 1 year (or 1000 hours) limited commercial warranties

Cons

  • Heavy weight of 390 lb (176.9 kg)
  • No noise level rating
  • High THD power is not suited for running sensitive electronics
  • Decent number of cases with technical issues

However, while the run time of 10 hours at 50% load and electric start are nice, these are also not the most exceptional details when it comes to large portable generators.

On top of that, the two years limited residential and one year (or 1000 hours) limited commercial warranties could be better too.

So if you are a big Generac fan, you could theoretically consider the GP17500E.

In practice, you likely want to play it safer at this price point and invest in a more reliable model that is potentially more budget-friendly too.

Brand ModelPower
Capacity
Run
Time
Quiet
Operation
THDReliability
Reputation
Fuel
Efficiency
Ease
Of Use
PortabilityPrice
Category
Current
Price
Generac GP17500E9.58?High
THD
7.57.584$$$$Check Price
Generac GP17500E performance on a score of 10 compared to similar alternatives

4. Westinghouse wGen12000DF

The Westinghouse wGen12000DF is the largest portable dual fuel generator thanks to its ability to run on propane and gasoline while offering up to 12000 peak watts (on gas).

Westinghouse wGen12000DF

There are a few stronger gasoline-only large portable generators too but it is worth mentioning the Westinghouse wGen12000DF as the biggest dual fuel model available.

The Westinghouse wGen12000DF also does not only offer a lot of power.

There are a few exceptional cases of technical issues but overall, the Westinghouse wGen12000DF is relatively reliable.

You get a nice run time of 11 hours at 50% too.

Although you could consider it, the noise levels of 74 dBA likely make it so you (and your neighbors) don’t want to run the Westinghouse wGen12000DF overnight.

Pros

  • Westinghouse wGen12000DF offers 15000 starting watts, 12000 running watts, 50 amps, and 240 volts (gasoline)
  • Dual fuel feature allows you to run on propane (LPG) too
  • Nice run time of 11 hours at 50% load
  • Less than 5% THD
  • Has electric and remote start
  • Four GFCI outlets
  • Version with CO sensor available too
  • Relatively positive customer reviews
  • 3 years limited residential and 1 year limited commercial warranties
  • A lot of customers

Cons

  • Heavy weight of 352 lb (160 kg)
  • Noise levels of 74 dBA are somewhat loud
  • A few exceptional cases of technical issues

However, the nice run time does allow you to enjoy your power for a long time before having to refuel.

In other areas, the Westinghouse wGen12000DF is very similar to the biggest Westinghouse on this list.

That means convenient operation thanks to the electric and remote start and an optional CO sensor if you want to add a layer of safety.

Something that positively stands out from certain alternatives is the nice warranties of the Westinghouse wGen12000DF.

That being said, with how quality this large dual fuel portable generator is, you should get a lot of power without too many issues.

Brand ModelPower
Capacity
Run
Time
Quiet
Operation
THDReliability
Reputation
Fuel
Efficiency
Ease
Of Use
PortabilityPrice
Category
Current
Price
Westinghouse wGen12000DF7.58.56<5%8.588.54.5$$$Check Price
Westinghouse wGen12000DF performance on a score of 10 compared to similar alternatives

5. AIVOLT 10000

The AIVOLT 10000 is the largest portable inverter generator at the time of research thanks to its built-in inverter and 10000 peak watts while using gasoline.

AIVOLT 10000

This portable generator is not the only big option with low THD power but it does have the built-in inverter.

In simpler words, the AIVOLT 10000 should be just a bit safer for your sensitive electronics and as you can see, relatively quiet.

With noise levels of 61 dBA (typically measured at 25% load and 23 feet away), this portable generator is barely louder than a standard conversation (typically around 60 decibels).

In combination with the 19 hours run time at 25% load, this makes the AIVOLT 10000 a good option if you want to run bigger AC systems and/or refrigerators overnight.

Pros

  • AIVOLT 10000 offers 10000 starting watts, 8000 running watts, 50 amps, and 240 volts (gasoline)
  • Parallel capability
  • Dual fuel feature so you can run on propane (LPG) too
  • Relatively low noise levels of 61 dBA
  • Good run time of 19 hours at 25% load
  • Good gasoline fuel efficiency
  • Less than 3% THD
  • Has remote and electric start
  • Four GFCI outlets
  • 2 years limited warranty

Cons

  • Not the most proven generator brand
  • Heavy weight of 299 lb (135.6 kg)

Because propane typically stores longer than gasoline, the dual fuel feature makes it easier to stay prepared for power outages and live off-grid too.

You do want to know that AIVOLT is not the most proven generator brand out there.

At the time of writing, the reviews are still reasonable overall.

However, it will be interesting to see how the AIVOLT 10000 holds up with more customers.

In short, the AIVOLT 10000 looks like an alright large portable inverter generator with quiet noise levels for now.

If you want to play it safe and don’t mind a bit less power, it could be smart to go for other good large inverter generators.

Brand ModelPower
Capacity
Run
Time
Quiet
Operation
THDReliability
Reputation
Fuel
Efficiency
Ease
Of Use
PortabilityPrice
Category
Current
Price
AIVOLT 100006.598.5<3%7.598.55$$Check Price
AIVOLT 10000 performance on a score of 10 compared to similar alternatives

Bonus: Westinghouse wGen9500

The Westinghouse wGen9500 is somewhat less powerful than many other options on the list but since it is our top pick for the best large portable generator, it does deserve a mention.

Westinghouse wGen9500

Something to note before going into the positives is that the Westinghouse wGen9500 produces high THD power that is not suited for sensitive electronics.

There are also a few very exceptional cases of shipping and technical issues.

That being said, the Westinghouse wGen9500 is still the most reliable big portable generator on this list.

Pros

  • Westinghouse WGen9500 offers 12500 starting watts, 9500 running watts, 50 amps, and 240 volts
  • Noise levels of 74 dBA
  • Run time of 12 hours at 25% load
  • Weight of 215 lb (97.5 kg)
  • Has electric and remote start
  • Four GFCI outlets
  • Version with CO sensor available too
  • Relatively positive customer reviews
  • 3 years limited residential and 1 year limited commercial warranties
  • A lot of customers
  • Relatively budget-friendly

Cons

  • THD of less than 23% is not suited for sensitive electronics
  • A few very exceptional cases of initial shipping and technical issues

With 12500 starting watts and 9500 running watts, the Westinghouse wGen9500 should provide enough power for many situations too.

Besides that, the Westinghouse wGen9500 is very similar to the other Westinghouse generators on this list.

One exception is that the run time of 8 hours at 50% load is not as impressive.

However, this could still be enough for a comfortable portable generator experience.

Especially if you consider the relatively budget-friendly price of the Westinghouse wGen9500.

Brand ModelPower
Capacity
Run
Time
Quiet
Operation
THDReliability
Reputation
Fuel
Efficiency
Ease
Of Use
PortabilityPrice
Category
Current
Price
Westinghouse wGen9500776<23%97.58.56$Check Price
Westinghouse wGen9500 performance on a score of 10 compared to similar alternatives

Related:

What is the biggest portable generator for home use?

The biggest portable generator you can use for your home is the Westinghouse wGen20000 with 28000 peak watts and 20000 running watts.

What is the largest output portable generator available?

The largest output portable generator available is the Westinghouse wGen20000 with 28000 peak watts and 20000 running watts.

If you want the best overall performance and 12500 starting watts is enough for your needs, the Westinghouse wGen9500 is generally the smarter choice.

Westinghouse wGen20000
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Author:

Mats is the founder and head editor of Generator Decision. With a combination of critical thinking, tireless research, and a healthy interest in electronics he helps people find the right generators and how to use these. At this point in the journey, Mats has done research on hundreds of portable generators.