Inverter Generators: Everything You Need to Know

Many people confuse an inverter generator for a portable generator. The reason is that both types of generators are relatively small and easy to move. And, because of their size, neither are able to power an entire home's worth of appliances at once.

That's where the similarities end.

There are many who say an inverter generator -- also known as an inverter -- is the perfect product to meet their backup power needs. Not only are they mobile, but their unique process for creating power is more efficient than other generators.

Some people are not as convinced.

In this blog post, we'll teach you everything you need to know about an inverter. Including their pros and cons. Then you can use AlltimePower's free Backup Power Calculator to determine if this unique type of generator is a match for your needs.

What is an inverter generator?

There are two categories of traditional generators you're probably used to seeing around homes. One is a standby generator, which is permanently installed near your house. Another is a portable generator that is moved to where you need it and attached temporarily to your home's electrical grid.

These traditional types of generators often use fuels such as gasoline, diesel, natural gas or propane to create power. They use these fuel sources to generate mechanical energy, also known as kinetic energy. The generator converts that kinetic energy into electricity. Specifically, it's an alternate (AC) electrical current.

An inverter generator has many similarities to this. They also require a fuel source such as gasoline. Most inverter generators are small enough to be portable, as well.

The main difference is how an inverter creates electricity.

Remember how we said a traditional generator creates AC electricity? An inverter does that, too. But it doesn't stop there. Next, it converts that AC current to a direct current (DC). In the final step, the electronic inverter converts the DC electricity back to an AC current.

If you're wondering why an inverter takes these extra steps, that's a good question. Here's the answer.

The dangers of harmonic distortion

AC power in the United States is meant to run at 120 volts and 60 hertz. The electrical grid is where you draw your power from at home in normal times. Today, that grid is incredible at sticking near the 120V / 60Hz standard.

That was not the case decades ago. The grid used to provide AC electricity that fluctuated. That fluctuation is known as harmonic distortion.

The lulls and spikes of electricity from harmonic distortion can damage the appliances receiving that current. Older appliances like refrigerators, electrical saws and toasters were designed to give room for the electrical grid's discrepancies.

Over time, technology improved and electricity from the grid became more consistent. New devices such as cell phones and laptops no longer needed to build room for harmonic distortion.

This all works great until a storm or extreme temperature event disrupts the grid, and you turn to your traditional generator for backup power. Generators don't provide the same consistent electricity as the electrical grid. When newer devices are plugged into an outlet powered by a traditional generator, harmonic distortion is a danger to damage or destroy them.

Inverter generators reduce harmonic distortion

Engineering experts have deemed that a 3% Total Harmonic Distortion (THD) is safe for sensitive hi-tech electronics like your phone. That is the percent of deviation from the standard 120V / 60Hz electrical current.

Traditional generators have THD levels as high as 9%. That's far higher than the recommended 3%. It's known as "dirty power" because the electricity is inconsistent. The lulls and spikes in electricity can be damaging.

Inverter generators, however, can reduce that risk. Their THD is frequently as low as 1%. That number is as reliable as power from your everyday electrical grid. That's why you're not afraid to plug your laptop into a wall socket when it's connected to the grid. It's also why you shouldn't be afraid to plug it in when it's powered by an inverter.

But how do inverter generators reduce harmonic distortion?

The simple answer is when the DC current is converted back to the AC current, it produces electricity that is smooth and consistent. Experts call this "clean" electricity.

Development of the inverter generator

This technology was originally called the "sine-wave inverter" because it produced a smooth electrical current in sine-wave form.

Its invention is relatively new. Honda Motor Company saw the damage a fluctuating current was doing to sensitive electrical devices. They strove to improve the quality of electricity produced by their portable generators.

Honda engineers were able to create the first generator with a stable electrical frequency in 1987. The EX300 used a 3-phase generation system, but could not be used to power all appliances. This is because the form of the current it generated was a rectangular wave.

By 1996, Honda was able to solve this problem. That year, they incorporated microprocessor technology into their EX500 generator. Prior to this, microprocessors were only used to devices like personal computers. The new technology, however, was able to turn fluctuating waveforms into a smooth and consistent sine-wave. This cleaner electricity could be used to power any device.

The pros of an inverter generator

Inverters can be more expensive than a conventional portable generator. But users often find the benefits to be worth it.

More efficient

As we mentioned earlier, all generators in the U.S. are trying to generate 120V / 60Hz electricity. As discussed, some are better at producing that consistent electricity than others. Still, all generators must operate at a speed of 3,600 RPM to reach that goal

Traditional generators attempt to stay at 3,600 RPM no matter what devices are plugged into the system. The generator produces the same amount of energy whether the circuit is supporting a handful of large devices or just a single laptop.

This is wasteful. A laptop requires much less energy than some larger appliances.

An inverter solves this problem by allowing your generator to produce more or less power depending on the devices plugged in. Its RPM output is designed to match what is needed. This conserves fuel. It allows your generator to run longer before it needs a refill. That saves users significant costs.

Environmentally friendly

Experts call the consistent electricity inverters produce "clean." That electricity is also cleaner for the environment. Because they use less fuel and produce less exhaust, inverters are a better choice for the planet than most traditional generators.


Though technology is improving this, generators are notorious for being loud. A standard portable generator produces 76-decibel noise. An inverter generator, on the other hand, produces between 50 and 67 decibels.

This means you can have a conversation next to the best inverters without straining to hear.


Traditional generators can be heavy. This is an important consideration, especially if you're moving your generator around.

Inverters are lighter and smaller models can be carried with a single hand. If you're looking for a generator to go camping with, an inverter will allow you to set it up with minimal effort.

Cons of an inverter generator (and a solution)

In addition to the price tag, inverters cannot produce the same level of power of a traditional generator. A traditional portable generator can produce approximately 17,000 watts. The most robust inverters produce in the range of 7,000 watts. Many offer a capacity of just 1,000 to 3,000 watts.

This limits how an inverter generator can be used. An inverter is great for powering a few small, important items. It won't be able to provide backup power for an entire home in the case of an outage.

There is, however, a solution.

Many models of inverters allow for something called "parallel capability." This means users can connect two inverter generators together to double their capacity. That could be enough, for example, to power a moderately-sized air conditioning unit.

But not all inverters are compatible for parallel capability. Make sure yours are when you buy them. To be safe, it makes sense to purchase two of the same inverters to ensure they can work together.

If you have questions about the wattage capacity you need to power specific items, use AlltimePower's free Backup Power Calculator.

The best use of an inverter generator

You can use an inverter generator to power a few small, important items in the case of a power outage. You can utilize parallel capability to up that capacity.

But the best use of an inverter is probably for recreational use such as picnicking, tailgating and camping.

The limited capacity is perfect for charging a device or two, and powering a small air conditioner on your RV. It can keep the music playing at your tailgate. And, because of its size, it's a piece of cake to move around during set-up. The low decibel output means you won't be disturbing neighbors in the park or campsite. And its fuel efficiency will save the environment and save you money on gasoline.

Outdoor recreation isn't the only use for an inverter, but it is a popular one. No matter how you use it, be sure to never operate your inverter indoors. This goes for all generators. The exhaust can be deadly if it isn't able to ventilate.

Inverter generators are an amazing technology that can be an important addition to your backup power strategy. Visit our website for a personalized assessment of your home power needs. We can help you find the right size and type of generator for your home and budget.

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