4 Best Diesel Generator For Home – Our Top Picks for 2022

Now, to help you pick the right diesel generator for your needs, let’s talk about important specs & features that you should know about.

Types of diesel generators

Diesel generators and generators, in general, are available in 3 styles – portable, inverter, and standby. We’ve seen generators of 2 on our top – portable and standby. 

To help you better understand their pros, cons, and use cases, let’s talk about each type more in-depth. Although we didn’t have any inverter generators in our reviews, we’ll still cover them so that you know what you are dealing with.

Portable generators

We’ve had one portable generator on our list – Generac XD5000E.

As evident from the name, portable generators are generators intended to be moved from worksite to worksite. They don’t have the highest output power on the market, but they are great for those projects where mobility is crucial.

Now, the phrase “portable generator” nowadays isn’t used to refer to every portable generator. Inverter generators, for example, are also portable by definition. However, what differs between generators marketed as “portable” and “inverter” is their circuitry.

Without diving too deep into technical terms, portable generators:

• Do not have throttling – their engine operates at max power no matter how many watts you actually need. This results in reduced energy efficiency and increased wear. But do note that some portable generators have an idle mode where the motor RPM is reduced when no power is being drawn. The idle mode doesn’t provide as much energy efficiency as full throttle control, but it’s at least something.

• Typically produce low-quality power that is unsuitable for sensitive electronics. We’ll cover the electricity quality more in-depth a little later.

• High noise levels, partly because the generator is always running at full power.

In contrast, portable generators are the cheapest of all generator types out there. 

Although the 2 downsides listed earlier are pretty serious, portable generators are still optimal for some use cases. If your tools don’t need clean power or if you are going to load your generator a lot, then a portable generator is a good option.

Note that some portable generators – like Generac XD5000E – produce way cleaner power than the average portable generator. However, there are some other details as well that should be covered separately.

Inverter generators

Inverter generators comprise an internal combustion engine, an alternator, and a DC-AC converter. Without diving too much into details, the technical design of inverter generators allows them to produce clean sine-wave power that is suitable for running sensitive electronics, such as computers or lights.

Aside from clean power, inverter generators also have the following benefits:

• High efficiency. Because inverter generators can throttle their motor, you are getting only as much power as you need. This results in higher energy efficiency, reduced fuel consumption, and longer service life.

• Low noise level. This benefit somewhat flows from the ability of inverter generators to throttle. When your power needs are low, inverter generators are much, much quieter than portable generators. Of course, at full power, these generators get noisy, but not as noisy as portable generators.

• Support of parallel running. Inverter generators can usually be connected with another inverter generator (typically of the same model) to satisfy higher power needs.

Standby generators

3 of 4 reviewed generators were standby diesel generators – huge, expensive, and powerful generators that can power a vast number of electrical devices, tools, and appliances at once.

Although standby generators have the same purpose as portable and inverter generators, their capabilities and feature sets are drastically different. More precisely, here’s what you get with a typical standby generator:

• Automatic operation: Standby generators can detect power outages and come online to supply electricity automatically.

• No need for refueling. Generally, because standby generators are hooked up directly to a fuel line, then don’t need any refueling. With that said, some generators may have small built-in tanks as well.

• Excellent durability. Standby generators are exceptionally durable and weather-resistant.

• High power capacity. Powered at thousands or tens of thousands of watts, standby generators can power entire homes.

Standby generators are typically used as backup sources for entire homes or workshops. If you absolutely want your appliances or tools to run at all times, then a standby generator is going to be the right choice for you.

With that said, keep in mind that standby generators are expensive, as well as have higher space needs and are more difficult setup.

Wattage

The next important thing to consider in a generator is wattage.

Generators are available in a broad range of wattages (or “sizes”) – from as little as 1,000 watts to as much as 60 kilowatts. Needless to say, a larger generator is going to be priced steeply, so you shouldn’t oversize your generator. On the other hand, your generator shouldn’t be too small for your needs.

To properly size your generator, consider what you are going to power. Electrical appliances all have power requirements that you can find in their spec sheets online or in the manual. Check out those to know roughly how much power you will need.

For smooth and easy sizing, here are a few tips to follow:

• Both starting (also called surge or peak) and running (continuous) wattages are important. Generators have two wattage specs – starting and running watts. Electrical devices usually need more power for startup than for continuous use. To meet these needs, generators can provide a short burst of power, but they can’t maintain that level of power continuously. Because of this, surge wattage is always higher than running wattage in generators.

Manufacturers usually provide the start/running power needs of their devices – make sure to check these out and get a generator that can satisfy them.

• Consider how many devices you will be using at a time. If you will be running only one tool or appliance at a time, then you don’t need a powerful generator – only as powerful as the tool requires. But if you do need to use two or more devices, then you should add up their power needs and look for a generator that can run them.

• If you aren’t going to use more than one tool simultaneously, then determine the requirements of your most power-hungry tool. If your generator can power up your most powerful tool, then it will handle everything else assuming you aren’t powering more than one thing at a time.

• Give 10-20% headroom. Once you’ve determined how much power you need, you may want to add 10-20% headroom just in case. Power spikes are rather common, and the added wattage should protect you, your devices, and the generator from harm.

Total harmonic distortion

If you care about the quality of your power, then pay attention to the total harmonic distortion (THD) as well. Basically, this spec shows how clean the electricity supplied by the generator is – the lower the THD, the better the quality.

Generally, THD lower than 5% or 6% is considered “clean” electricity that is suitable for sensitive electronics, like household appliances. Lower quality generators may have THD of around 9-15%, or perhaps even more. Such high THD will probably be only suitable for powering tools or other low-demand equipment.

Keep in mind that generators with low THD cost a lot, so before investing, make sure that you even need clean power.

Power outlets

No matter what generator type you are going for, make sure to check what kind of outlets they have. If you have particular needs, then ensure that you are investing in a generator that can satisfy them. Check the available voltage as well – some generators allow you to switch from 120 to 240V, and a few also have DC outlets.

Starter style

Standby generators usually power on automatically, so the starter style matters only in portable and inverter generators.

Starters can be electric or manual recoil (also called pull). Electric starters are convenient in that they allow you to start up the generator with a push of a button. These starters require batteries to operate though.

Recoil starters are engaged via a rope, and they don’t require battery power. However, they are less convenient and reliable than electric starters, often requiring multiple pulls.

Electric starters are generally preferable due to their convenience. However, having electronic AND recoil starters is a good idea since electronic starters tend to malfunction.

Safety features

Safety features are important in generators as well, especially those used very heavily. Among features that you may want to look for are:

• Automatic overheating shutoff.

• Low oil pressure shutoff.

• GFCI power outlets & circuit breakers.

• Waterproof exterior components.

• Warning lights to let you know of malfunctions.

Maintenance & convenience features

Apart from safety, you may also want your generator to be convenient. Like with safety, this especially matters in heavy use. 

Among maintenance & convenience features to look for are:

• Self-diagnostics.

• Maintenance reminders.

• Voltmeters.

• Hour meters.

Fuel tank size & runtime

Diesel generators typically have fuel tanks, but not always – standby generators, for example, may not have any tanks, instead relying on an external fuel source. As for portable or inverter diesel generators, they all have integrated tanks.

When it comes to tank size, you should pick a generator based on how long you want to keep your devices running without refueling. A larger tank, needless to say, translates to longer runtime.

Manufacturers typically indicate their generators’ runtime in the spec sheet. Usually, the runtimes are given for 1/2, 1/4, or full load.

Note that some manufacturers provide runtime only for 1/2 load, while others give figures for 1/4 load. You can’t directly compare the runtimes of two generators if they are given for different loads. If possible, find comparable specs and base your decision on them.

Noise level

Diesel generators can get really noisy. No generator is quiet – however, some are quieter than others.

If you do care about noise, then find the noise level in the spec sheet of the desired diesel generator. Usually, the noise level is measured in decibels, or dB. Manufacturers provide the noise levels of their generators at a given load (such as 1/4 or 1/2) and at some distance (e.g. 10 or 20 feet).

Because manufacturers measure and list generator noise levels differently, you can’t always directly compare two generators to each other. Like with runtime, you should ideally find comparable specs and make comparisons with them.

Portability

Want an easy-to-carry generator? Then pay attention to how portable the desired model is.

Obviously, this point applies only to portable and inverter generators – standby generators aren’t intended to be moved anywhere.

Since manufacturers employ a broad range of features and tricks to make their generators portable, we can’t outline them all here. With that said, the most basic portability features to look for are wheels, carrying handles (with very light generators), and towing handles.

Some generators (like Generac XD5000E) have more unique and special features like lifting eyes. If you want portability, be on the lookout for such things too.

Size & weight

Finally, consider size and dimensions.

The size will matter with any type of generator. Standby generators are huge and thus need space in your backyard. Portable generators are rather compact, but if you want something space-efficient, dimensions will matter in them too.

So no matter what you are intending to buy, make sure to measure how much free space you have and buy a generator accordingly.

As for weight, it will only really matter with portable generators. If you are going to transport a generator in your pickup or RV, then you should make sure that it doesn’t exceed the weight limits of your vehicle. Not only that, but a heavy generator is less convenient to transport.