Diesel generators are true workhorses, designed to deliver reliable power day after day, year after year.
There aren’t many portable diesel generators on the market, and they can be expensive. But as we discuss in our buyer’s guide, when it comes to generators, the purchase price is not the only thing to consider.
Before we get into the detailed pros and cons of diesel vs gas, let’s have a look at the best portable diesel generators currently on the market.
Our Top Pick
Best Portable Diesel Generator Reviews
Best Overall: DuroStar DS7000Q
Max power – 6500W; Continuous power – 5500W; Tank size – 3.8 gallons; Run time – 12 hours (50% load); Weight – 305 lbs
The DuroStar DS7000Q is our pick for the best all-around portable diesel generator, offering a good balance of power, run time and features for a competitive price.
It delivers 5500 watts of continuous power with a surge power output of 6500 watts – handy for starting up power-hungry appliances or power tools. The 3.8-gallon fuel tank gives a decent run time of 12 hours on half load. This isn’t anywhere near what the Generac 6864 offers, but it’s more than most gas or dual fuel generators.
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The electric start makes firing up the generator easy, and there’s a single-pull recoil start as a backup. One nice feature is the wireless remote start, which means you can start the generator from the comfort of your front porch.
There’s the usual range of outlets, including a 240V twist lock outlet and a DC outlet, and the control panel also features a voltmeter, low fuel indicator and circuit breakers. One thing it’s lacking is an hour meter, but you can pick one up pretty cheaply to keep track of maintenance intervals.
It’s not a quiet generator but it’s no noisier than gasoline generators of a similar size. However, at over 300 pounds, it is a lot heavier. You won’t be lifting this beast easily but fortunately, it comes with a wheel kit to assist with portability.
Overall, this is a great value generator, and the three-year warranty should give you a bit extra peace of mind.
- Remote start
- Good value
- Good runtime
- 3-year guarantee
- No hour meter
Best Run Time: Generac 6864 Portable Generator
Max power – 5500W; Continuous power – 5000W; Tank size – 12 gallons; Run time – 32.4 hours (50% load); Weight – 254 lbs
The Generac 6864 has a similar frame design to portable gas and dual fuel generators, though at 254 pounds, it’s significantly heavier. The integrated lifting eye may help when moving the generator around as well as providing an attachment point to secure the generator.
The engine gives 5000 watts of running power with an additional 500-watt boost for starting up. This is a reasonable output for a portable generator, but you’re unlikely to be able to run everything in your house off it.
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It has an electric start as well as a pull cord and in addition to two twist lock outlets (one giving 240V power), there are four standard 120V outlets. The hour meter on the control panel helps you track usage for maintenance purposes.
What stands out about this diesel generator is the run time. It has a massive 12-gallon fuel tank which gives you over 32 hours of power when run at half load. None of the other generators we’ve reviewed comes close to this.
With this huge run time, you may wonder why it’s not featured as our top pick.
Unfortunately, there are a couple of significant disadvantages to this generator which could be deal-breakers. Firstly, it’s extremely noisy. Generac doesn’t give a specific decibel rating, but it’s loud enough that you’d need to wear ear defenders to spend any time near it. This isn’t ideal if you want to keep a low profile or if noise at home bothers you.
Secondly, it doesn’t come with either a wheel kit or a battery – you have to buy both separately. The generator also won’t run without the battery as it’s needed to power the fuel cut-off system. This could be an issue in a post-disaster situation where the correct battery may be hard to come by.
Finally, the recoil starter is really hard to use, even if you’re used to starting generators. As long as the electric start works, this isn’t an issue, but we always like to have a workable back-up option.
- Large tank with long runtime
- Hour meter to track maintenance intervals
- Lifting eye for security and transportation
- 2-year parts and labor warranty
- Extremely noisy
- Wheel kit comes separately
- Requires battery to run
- No DC outlet
Best Budget Diesel Generator: Sigma 7000W Silent Diesel Generator
Max power – 7000W; Continuous power – 5500W; Tank size – 4 gallons; Run time – 8 hours (50% load); Weight – 385 lbs
The Sigma Silent Diesel Generator is a low-cost, no-frills option if you’re on a budget. It delivers 5500 watts of power with an additional 1500 watts of surge power – enough to power basic household appliances such as a refrigerator and microwave, or a water heater or air conditioning system.
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The 4-gallon fuel tank gives a run time of around 8 hours on half load. This isn’t as long as the other models we’ve reviewed, but there’s the option to connect it to an external fuel tank for more continuous power.
It’s pretty quiet for a diesel generator, producing 68 decibels at 21 feet. There are two 120V outlets, a twist lock 120V, twist lock 120V/240A and a DC outlet for charging batteries.
The main downside is the weight. At 385 pounds, it’s more than a hundred pounds heavier than the Generac and Amico generators and eighty pounds heavier than the DuroStar. While it does come with wheels for maneuverability, it won’t be easy to move the Sigma generator around.
As a less well-known brand, you may have concerns about the reliability and longevity of the Sigma 7000W generator. This is something to weigh up against the price (which is significantly lower than other diesel generators) when deciding on the best diesel generator for your needs.
- Low cost
- Relatively quiet
- DC Output
- Very heavy
- Short run time compared to other models
Best Quiet Diesel Generator: AMICO Power AHW6000LE Diesel Welder and Generator
Max power – 6000W; Continuous power – 6500W; Tank size – 3.3 gallons; Run time – 12 hours (50% load); Weight – 268 lbs
The Amico AHW6000LE is both a welder and a generator, though if you’re planning to use it for welding, be aware that welding leads aren’t included.
As a generator, it’s the most powerful of the portable models we’ve reviewed. This makes it a good choice for larger households or those with energy intensive appliances such as an air conditioning unit or a water heater.
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The 3.3-gallon tank gives a run time of up to 12 hours on half load and there’s the usual range of AC outlets plus a DC outlet. The control panel has a useful voltmeter and hour meter to help you track usage for maintenance purposes.
It’s the quietest of the generators we’ve reviewed with a rating of 65 dBA at 7 meters. It’s also one of the lightest, though this is all relative! Unlike the Sigma and DuroStar generators, which are four-wheeled models, the Amico has two wheels and a pair of handles for moving the generator around.
The AHW6000LE only has a one-year limited warranty. If you’re planning to use your generator infrequently (e.g. for emergency use only) then a model with a longer warranty period may give you more peace of mind.
- More powerful than other diesel generators
- Relatively quiet
- Can be used for welding
- Only comes with a 1-year warranty
- Requires battery to run (supplied)
Pros and Cons of Diesel Generators
Diesel generators are a lot more expensive and harder to source than gasoline-powered or dual fuel generators. But are they worth it? Here’s a summary of the pros and cons:
Advantages of Diesel Generators
- More efficient than gasoline-powered generators
- Diesel engines typically run for longer than gasoline or propane generators, making them a more reliable long-term power source
- They have fewer elements requiring routine maintenance compared to gas generators
- Cheaper to run than gas or propane (depending on relative fuel costs)
- There’s a lower fire risk as diesel is less flammable than gasoline
- Diesel may be easier to source in a post-disaster situation
Disadvantages of Diesel Generators
- Diesel generators are more expensive than gasoline generators
- They can be harder to start in cold weather
- Diesel generators are noisy. However, many manufacturers have included some element of soundproofing in their designs and several of our recommended models are as quiet as the dual fuel generators we reviewed.
- They’re more expensive to repair
- They are heavier than gas or propane-powered generators
- Diesel is a dirtier fuel than both gas and propane
What to Consider When Buying a Diesel Generator
There are very few portable diesel generators on the market compared to gas or dual-fuel generators. Diesel engines are expensive, heavy and largely targeted at the agricultural market rather than homeowners. However, for many preppers, their reliability over the long term makes them worth the extra cost.
Here’s what you need to consider when buying a diesel generator:
All the portable generators we’ve reviewed are mid-sized in terms of power output. If you need a larger output model, such as a 10,000-watt generator, then you’ll need to install a static generator.
If you think you need more power, but want the benefit of portability, then it may be worth looking at whether you can adjust your usage to make the most of the generator output. For example, an electric water heater may require 4000 watts of power, which doesn’t leave much for other appliances. But if you power your water heater at night when you’re not using cooking equipment, washing machines, or a space heater, you can still have hot water in the morning.
Size and Weight / Portability
We’ve defined a “portable” generator as one with wheels that you can move around or load into a vehicle. That said, even “portable” diesel generators are extremely heavy and will require several people to help move them.
Some models, such as the Generac, have a lifting eye that could attach to a pulley system to make it easier to lift the generator onto a trailer or into a vehicle.
One of the advantages of diesel generators is that they require less maintenance than gasoline-powered generators. But if they do go wrong, they can be more expensive to repair.
If you’re going to be relying on your generator as your sole source of power during emergencies and disaster situations, then it’s worth learning a bit about how generators work. This will allow you to keep on top of your generator’s maintenance and deal with any issues that arise.
Although diesel generators have a higher upfront cost than gas or propane generators, they will cost less to run and have a longer lifespan. For this reason, it’s worth comparing the lifetime cost, or the cost over a specific time period (say, five years) to get a better comparison of what you would pay overall.
Generally speaking, if you’re only likely to be using your generator occasionally and won’t be running it at full load, you may be better off buying a gas generator or dual fuel generator. If you want to push your generator to the max and will be using it a lot, diesel may be the way to go.
Diesel generators are noisy and may attract unwanted attention. Read about some simple steps you can take to keep a generator quiet.
Diesel fuel is generally easier to store and lasts longer than gas, if you are planning for a survival scenario this is an important factor to consider. Read more about diesel storage.