8 Best Generator With Low THD (Inverter, Dual Fuel & Other Options)

Generators are gadgets that will supply you with power during a power outage or load-shedding. All of them will have THD (Total Harmonic Distortion). But, the generators need to have THD as low as possible. 

Honda, Westinghouse, and Generac are the best generators with low THD. These can provide less than 5 to 6% of THD, which is quite appreciating. Others include DuroMax, Champion, Jackery, and Pulsar. However, Westinghouse & Champion are best in terms of noise.

It is always better to own generators with low THD. High THD generators can damage the sensitive electronics of your house. This article will discuss some best generators and inverter generators with low THD.

Check out our list of top-handpicked products for all your electrical, appliance, and HVAC system needs to keep your home running smoothly.

This post includes some affiliate links.

What is a THD?

THD stands for Total Harmonic Distortion. 

It is the measurement of the distortion produced by the amplifier of the generators. 

The generators transform the kinetic energy into electrical energy by moving the magnetic fields created by the coils around the armature. 

The magnetic fields will interact and generate voltage and frequency.

When the additional voltage is generated, the interaction makes a mutual inductance contributing harmonics to the output signal generated by the 3-phase, 4-four wire AC system working at 50Hz. 

These additional frequencies are called harmonic distortions. 

Generators with low THD will produce much more high-quality electricity than those with higher THDs.

Generators with high THD can severely damage several sensitive electrical devices like plasma televisions, computers, modern HVAC systems, amplifiers, air conditioners, etc. 

It can also interfere with the power lines. 

That is why experts recommend using generators that have low THD. 

Best generators with low THD

Before you choose a generator with low THD, you must know what a good THD for the generator is. 

Generally, the best generators will have a THD level of around 6%. 

Some standard generators have 9% to 15% of THD. It is acceptable for the lights, sump pumps, and power tools. 

But since the THD is quite high, it can damage sensitive appliances and reduce their lifespan. 

Most publishers do not expose the THD percentage of the generators. So, be careful while buying generators. 

If you do not see any THD percentage on the label of the generators, consider it unsafe for your house. 

Below are some best generators with low THDs. Also, I will share my final verdict and my best pick at the end of this post, but first, go through the list and check the pros and cons of each one of them.

1. Honda EU2200i

Honda EU2200i 2200-Watt 120-Volt Super Quiet Portable Inverter Generator with CO-Minder - 49-State

THD rate – Less than 6%

Rating – 5/5 

Since the THD rating is less than 6%, it would be the best for your house, especially if you live in a suburban neighborhood and want to keep disturbances at low levels.  

The generator is also good for camping and events where you will require quiet outdoor power. 

The Honda generator is great because of its compact design and weight, less than 50lbs. 

Its nature of producing very less noise while operating makes it more attractive. 

The THD of the generator is less than 6% and, thus, perfect for easy transportation and fitting at any location. 

You can close the vent on the gas cap and prevent fumes from coming out. It controls the strong smell in the surrounding that most generators release.

This model of Honda also comes with a ‘low oil’ alert, where the generator reduces the engine’s operation.

That stops overworking of the generator and causes less damage. 

The ‘fuel shut-off’ closes the generator when most of the fuel is used. 

It prevents the generator from using any stale fuel and harming the machine. 

The machine also monitors the carbon monoxide levels. 

It shuts off automatically without reducing the CO levels too low, which can be dangerous. 

The generator will also connect to another generator of the same model number to give you an additional power supply. 

You can generate the power using your phone’s Bluetooth and dedicated apps. 

Honda EU2200i gives a maximum output of 120 volts and conserves energy. 

It can power the refrigerator, HVAC system, and also microwave. 

However, you still have to limit the overall power usage.

The generator will work 8 hours with one fuel tank, delivering reliable and clean power.

2. Westinghouse WGen 12000DF

Westinghouse 15000 Watt Dual Fuel Home Backup Portable Generator, Remote Electric Start, Transfer Switch Ready, Gas and Propane Powered, CARB Compliant

THD – Less than 5%

Rating – 4.8/5

The generator is great for big houses that use too much electricity daily. 

The generator operates using gas or propane and can run up to 11 hours using one single fuel tank. 

This Westinghouse model has a remote start. So, you can stay in bed to start it.

It can run all household appliances along with entertainment devices. 

Due to its THD level lower than 5%, it will keep sensitive electronics safe. 

The generator model does not have any ST switch, but you can buy it separately because it has an ST switch outlet. 

You can connect the generator to the breaker box using a transfer switch to switch it on automatically whenever needed. 

You can also use GenerLink. 

Despite so many advantages, one drawback is the generator’s weight is very heavy, around 300 pounds, thus, making it unfit for transportation. 

But, the model can tolerate heavy storms and is ideal for areas with such rough weather. 

3. Generac XT8500EFI

Generac XT8500EFI Portable Generator

THD – Less than 5%

Rating – 4.8/5

The new Generac generators have ‘True Power Technology, for which the THD has been minimized to less than 5%. 

Lower THD helps keep your electrical machines safe, especially sensitive ones. 

Like the Westinghouse, this generator has a low oil shutdown feature to protect the machine from quick damage. 

Control guards and covered outlets save the generator the weak areas of the generator so that it can tolerate heavy storms. 

The generator weighs 233 pounds, heavier than Honda but lighter than Westinghouse. 

The machine has 10-inch wheels and fold-down locking handles, which help you move and store.

One attractive thing about the generator is it does not have a carburetor. So, it can use fuel more efficiently but emits low emissions. 

That is why you do not get any smell from the generator. 

The generator also has an idle control, running for around 9.5 hours on a single fuel tank. 

Sometimes, the online review declares it to be a little noisy. So, you must check it before buying. 

Best inverter generators with low THD

The inverter generators are slightly different from the regular generators. 

Inverters are the latest type of generators with the latest technologies and updated versions. 

They have less THD than the generators discussed earlier, i.e., less than 3%.

The regular generators can produce AC (alternating current) current, but the inverters produce 3 phases of current. 

The inverters will give a clean current, but regular ones do not produce clean energy. Clean energy is safer for sensitive appliances. 

However, some inverter generators will be good for sensitive electrical appliances. 

1. Westinghouse iGen2200 Inverter generator

Westinghouse 2200 Watt Super Quiet & Lightweight Portable Inverter Generator, Gas Powered, Parallel Capable, Long Run Time

THD – Less than 3%

The generator is quite portable and, thus, easy to carry around from one place to another. It weighs only about 46lbs.

Additionally, it is designed with a kickstart device and wireless connections. 

You can also make it work by using your phone, thus letting you stay in bed and start. 

But you need to stay within 80 feet of the generator. 

You can run the generator for at least 12 hours with one single fuel tank. 

The generator comes with a steel frame responsible for reducing noise. 

It creates a noise of around 52dBa, which is negligible if you live in a dense residential building. 

Less than 3% is quite a low THD. 

So it will not create a very loud noise and disturb anyone. 

It contains 4 outlets, 2 sockets, a 30 amp power source, and 2 sockets with 120v 20 amp power source. 

The generator is also water-resistant and, thus, can handle heavy rains. 

The only problem with this generator can be with the oil change. 

It is quite difficult due to the position of the dipstick. 

2. Champion 2000-Watt Generator

Champion Power Equipment 100692 2000-Watt Portable Inverter Generator, Ultralight

THD – Less than 3%

This generator stands out as one of the most affordable products. 

This generator has very low THD, less than 3%, which is quite good. It will create noises around only 53dBa. 

The Champion generator will function from one single tank for around 11 hours. 

It has an automatic low-oil shut-off feature, saving your generator from using too much when the level is low. This feature keeps your machine safe and long-lasting. 

You can move the generator easily from one place to another due to its lightweight. It will weigh only around 43.4lbs. 

The generator has a Fuel Fill Assist LED with a push-button light on the right side of the handle. 

The LED light illuminates the petrol fill area and makes you understand the refueling time in the dark. 

The generator’s smart ‘Economy Mode’ reduces electrical overload, functions quietly, increases engine life and saves fuel economy.

The two best types of Champion generators are:

Best Dual Fuel generators with low THD

Dual Fuel generators are multi-fuel generators that use gasoline or propane as fuel to supply electricity to the appliances and your house. 

Below are some best dual-fuel generators:

1. Champion 2000-watt Power Equipment 100402 generator

Champion Power Equipment 100402 2000-Watt Dual Fuel Portable Inverter Generator, Parallel Ready

It is an inverter generator belonging to the Champion inverter 2000-watt series, which I already discussed earlier. 

It will keep the generator on for 11.5 hours on gasoline at 25% load. 

The generator is also lightweight, around 40lbs, and has very low THD, less than 3%. 

The noise level is around 53dB. It is quiet, but not as quiet as other best generators having low THD.

2. Westinghouse iGen4500DF inverter generator

Westinghouse 4500 Watt Super Quiet Dual Fuel Portable Inverter Generator, Remote Electric Start, Gas & Propane Powered, RV Ready 30A Outlet, Parallel Capable

It is an advanced hybrid generator that provides clean and stable power for the sensitive electrical appliances of your house. 

The generator runs on gasoline and propane and provides up to around 4500 watts. 

It has 4 120V outlets that you can easily use for most household appliances. 

The generator will give up to 4500W for 12 hours. 

It can run up to 18 hours, which is great. 

You can run the generator with a remote, provided you stay within 260 feet of the generator. 

But, the generator is slightly heavier, weighing around 104lbs, and is expensive. 

3. DuroMax XP2300iH

DuroMax XP2300iH 2300-Watt 80cc Dual Fuel Digital Inverter Hybrid Portable Generator, Blue

Its running time is 6.5 hours at 50% load. 

The generator is quiet due to the 52dB sound level and less than 3% THD. 

Though the machine is portable, it is slightly heavier, not too much, and more expensive than the other products. 

It weighs around 60lbs.

You can run it on either gasoline or propane. 

The generator gives clean energy and prevents power surges, which is good for sensitive appliances like computers, mobiles, and tablets. 

Despite so many good sides, the generator is heavy, and the run time is short. 

Other generators with low THD

The above-discussed generators are the best ones with low THD. 

They have very good features and are great for houses. 

You can even carry some of them for camping trips.

Except these, there are a few more generators with less THD. Below is a list:

  • DuroMax XP1000E Gas-Powered Portable Generator 
  • DuroMax XP13000HX Dual Fuel Portable Generator 
  • Jackery Portable Power Station Explorer 240Wh backup, Lithium Battery, 110V/200W Pure Sine Wave AC Outlet, Solar Generator
  • Generac GP2500i Inverter
  • Pulsar 5,250W Dual Fuel Portable Generator with Switch and Go Technology, PG5250B

Can I lower the noise of a generator?

If you already have a generator that is quite noisy, you might need ways to lessen the noise.

Some simple tips to reduce noise are:

Get a quiet generator box.

Build up a quiet generator box for your noisy generator. 

But, you must ensure that the generator does not overheat and you can easily access the power cord while in use. 

Get a quiet box from a hardware store and buy a readymade weather cover. 

Add a muffler to the generator.

Sometimes, some generators can have around 75dBa sound. 

Adding a muffler to the generator reduces the noise of your generator. 

If you are inexperienced in welding and other mechanics, call an expert mechanic who can do such things. 

Also, consult an electrician before doing it.

Water absorption 

It is a very simple way of reducing the noise of the generator. 

All you need is a hose, water, and a bucket. 

Attach one end of your hose to the generator exhaust and put the other end in a bucket filled with water. 

Use a flex tube made of galvanized metal to prevent fire hazards. 

The sound will go through the tube and get muffled by the water. 

But you must keep the generator away from the water. 

Add a small hole in the hose at the high point. 

It will allow the passing out of the extra airflow and water. 

It also keeps the water from sucking back to the generator. 

Rubber absorption

This method is used to reduce medium noises. 

Your generator will make too much noise if sitting over a concrete or hard area because the unit shakes when the engine runs. 

Placing your generator over some soft surface, like rubber, can reduce the noise by suppressing the noise caused by the vibrations. 

If you have gone camping or RVing, find a soft place to place your generator and avoid the noises.

Dry soil will also create such noise. So, you can use a rubber mat under the generator. 

Plywood boards

Another way of numbing the generator noise is by using plywood boards. Besides, the method is quite cheap.

Lean 2-3 plywood boards around the generator. 

Ensure you are not blocking the exhaust and airflow or leaning the board against the machine. 

Create a box or triangle around your generator without touching the machine. 

Redirect exhaust pipe

Sometimes, repositioning the exhaust pipe can reduce the generator noise. 

Keep the exhaust pipe vertically to redirect the noise upward and reduce the noise. 

The sound will move upwards and vanish into the sky. 

So, which one is the best?

In the end, I would say that different generators are best in different points, for example:

Final thoughts

There are multiple generators with low THDs. 

Some of them are regular generators, and some are inverter generators. 

All the generators mentioned in the article are good because they have less than 6% THD, which means they will function silently. 

The inverters function more silently, as most of them have less than 3% THD.

If you have a generator with more noise, you can try the methods of noise reduction I have shared.

The procedures might not completely reduce the noise but will do it to a great extent. 

Also read:

Reference: Total harmonic distortion, A low THD three-level rectifier for Gen-Set applications, Induced EMF THD Reduction Design, Honda owner manual, Westinghouse owner manual.

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Arthur Smith

Howdy! I am Arthur Smith, an electrical engineer who is extremely passionate about electronics. I have lived in different parts of the US and currently reside in Wisconsin. I am one of those rare children who knew what he wanted to study and do in life right from the start. I was a curious child who wanted to know how switches work and how the AC works, and I would always observe my dad whenever he would handle the wires and fix things around the house. I currently work as an electrical engineer at a reputed company and write for this blog. And I read loads of books or play video games in my free time.

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