Pure Sine Wave Inverters: Necessary or Overkill?

They're more expensive, but are they worth it?

By
Jeremy Laukkonen
Jeremy Laukkonen
Jeremy Laukkonen
Writer
  • Shoreline Community College
Jeremy Laukkonen is automotive and tech writer for numerous major trade publications. When not researching and testing computers, game consoles or smartphones, he stays up-to-date on the myriad complex systems that power battery electric vehicles .
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Updated on May 23, 2024
Reviewed by
Jessica Kormos
Jessica Kormos
Reviewed by Jessica Kormos
  • Saint Mary-of-the-Woods College
Jessica Kormos is a writer and editor with 15 years' experience writing articles, copy, and UX content for Tecca.com, Rosenfeld Media, and many others.
lifewire's editorial guidelines

Most electronic devices can work without a pure sine wave inverter, but there are some important points to consider before buying one. It's helpful to know why the differences between pure sine wave inverters and modified sine wave inverters might matter.

The two main concerns are efficiency and unwanted interference from the extra harmonics in a modified sine wave. A pure sine wave inverter is beneficial because it:

  1. Efficiently powers devices that directly use the alternating current (AC) input.
  2. Powers sensitive devices like radios that can experience interference with modified sine waves.

Understanding these benefits can help you choose the right inverter for your needs.

Do You Need a Pure Sine Wave Inverter? 

Some useful questions to ask yourself to determine if you need a pure sine wave inverter include:

  • Does the device or appliance use a motor?
  • Is the device a delicate piece of medical equipment?
  • Does the device or appliance use a rectifier?
  • Can the device be powered by a DC adapter?

If you answered yes to either of the first two questions, you may need a pure sine wave inverter. If you answered yes to either of the second questions, then you may be fine without one.

pure sine wave
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When a Pure Sine Wave Inverter Is Necessary

A modified sine wave inverter will work for most situations, but there are some cases where it might cause damage or be less efficient. Devices that use AC motors, like refrigerators, compressors, and microwave ovens, tend to run more efficiently with a pure sine wave inverter. They can still function with a modified sine wave, but it might lead to inefficiencies, excess heat buildup, and potential damage.

If you use a CPAP machine, especially one with a heated humidifier, it's a good idea to use a pure sine wave inverter to avoid damaging the unit.

Always check the manufacturer's recommendations, but most CPAP manufacturers suggest using a pure sine wave inverter.

When a Pure Sine Wave Inverter Isn't Necessary

If your electronic devices use rectifiers to convert AC to DC, you probably don't need a pure sine wave inverter. Don't be mistaken, it will still work just fine with these devices. However, if you have the budget and want extra peace of mind or to future-proof your setup, a pure sine wave inverter is a good choice. It will work well even in situations where you don't need one.

However, most electronic devices run well on a modified sine wave. For example, laptop computers, phone chargers, and all other equipment that uses a rectifier or AC/DC adapter to take an AC input and output DC to the device will typically work fine without a pure sine wave inverter.

With many of those devices, you can cut out the middleman and use a DC-to-DC converter that steps the 12V DC from a truck's electrical system either up or down, without first converting it to AC before converting it back to DC. This is the more efficient route to take, so it might be worth looking into if a 12V adapter is available for any of your devices.​

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