What are STETZERiZER Filters for?

STETZERiZER Filters remove or reduce high-frequency pollutants on the electrical wiring in your home or business.

Can I use U.S. model filters in other countries and vice versa?

Short answer – no. STETZERiZER filters designed for use in North America (United States, Canada, the Caribbean) can only be used in countries with the same type of electrical distribution system – 110V, 50/60Hz AC. Much of the rest of the world operates on 220-240V, 50 or 60Hz power, and different countries or regions use different types of plugs. While plug adapters are widely available, it is important to know the voltage and frequency of the electrical system on which you will be using an electronic device and to check the device to be sure it is designed to operate within those voltage and frequency ranges.

The various international models of STETZERiZER filters require not only different plug types, but also different internal components than the U.S. model. The differing internal components are required in order to allow for proper, effective operation and also to obtain certifications from standards-setting organizations like CE and SII – meaning, we’ve designed each international model of STETZERiZER filter with your safety in mind. For these reasons we recommend using only those filters that are specifically designed for the electrical system in your particular country. See our list of STETZERiZER Distributors to find a dealer near you.

My outlets are grounded/ungrounded – will Stetzerizer filters work for me?

The North American model of STETZERiZER filters are equipped with an ungrounded plug (Type A, 2 prong). They can be used in both grounded and ungrounded outlets operating at 110V, 50/60Hz without issue.

Is there a grounded version of the Stetzerizer filter?

No, we do not make a grounded (3-prong) version of the North American STETZERiZER filter. Why not? To put it simply, there is no need. STETZERiZER filters act as a short to high frequencies, and since current oscillates on the hot and neutral wires of the electrical system, it is appropriate to short the hot to the neutral with the filter in order to neutralize these high frequencies. The National Electrical Code (NEC) in the United States mandates that the neutral and grounding conductors be bonded at the main service panel; with the neutral and ground bonded, Stetzer filters will therefore short out high frequencies on the grounding conductor as well.

Can I use the Microsurge meter outside the United States?

Yes. The STETZERiZER Microsurge meter is designed to operate on 110V-240V, 50-60 Hz AC power. Unlike STETZERiZER filters, where different models have been designed for use in specific countries or regions, the Microsurge meter can be used universally with the appropriate plug adapter. Stetzer Electric does not sell plug adapters, but universal or region/country specific adapters are widely available on the Internet and elsewhere.

How can I tell if I need STETZERiZER Filters?

If you and your neighbors have electronic equipment connected to electrical outlets, you need STETZERiZER Filters.  The STETZERiZER Microsurge Meter can be used as an aid in determining exactly how many filters you may need.

How many STETZERiZER Filters do I need?

It usually takes 20 filters to effectively “clean up” the average home.  Homes with more electronic equipment (i.e. computers, printers, fax machines, televisions) may require more filters.


If this describes your home you may need to use several power strips or triple tap adapters to accommodate the use of STETZERiZER Filters in areas of your home with more electronic equipment.

What is the lifespan of STETZERiZER Filters?

STETZERiZER Filters are not like oil filters that fill up and become less efficient with use; they are an electronic component and should last a lifetime.

Do I need to hire an electrician to install STETZERiZER Filters?

No.  STETZERiZER Filters are designed so that anyone can properly install them.  Simply plug the filters into an electrical outlet or power strip.

How do I install STETZERiZER Filters in my home?

Installing STETZERiZER Filters is as easy as plugging in a toaster – simply plug your STETZERiZER filters into any standard electrical outlet, and that’s it!

You do need to plug them in in the right places though, and we provide detailed instructions for doing so right along with your order. Installation instructions are also on our website here, and if you still have questions or you aren’t getting the desired results, you can see if your questions are answered on the FAQ page, or you can contact us using one of the options on the Contact page.

How can I tell if a STETZERiZER Filter is working?

The only way to tell if a STETZERiZER Filter is working is with the use of an oscilloscope or specially designed meter like the STETZERiZER Microsurge meter.  However, many of our customers claim they can tell their filters are working because they start to feel better once the proper number of STETZERiZER filters have been installed.

In any case, we highly recommend purchasing the STETZERiZER Microsurge meter along with your STETZERiZER Filters.  We want you to know that your STETZERiZER products are working properly to provide a “clean” electrical environment for you and your loved ones.

I plugged in a STETZERiZER Filter and it started humming. Should it do this?

No.  When a STETZERiZER Filter is humming, it is overloaded.  To resolve this problem, simply plug in more filters.  Remember, it takes an average of 20 filters to clean up a home; one or two filters simply cannot do the work of twenty.

I plugged in a STETZERiZER Filter and there was a spark. Is this normal?

Yes, it is normal for the filters to spark or make a “popping” sound when they are being plugged in.  This should not hurt you, your electronic equipment, or your filters.

What are GS Units?

GS (Graham-Stetzer) Units are a measure of the average magnitude of the voltage surge (i.e. the rate of change of the voltage with time, or dV/dt) at the electrical socket.  One GS Unit is 24 Volts per second.

Why are international models of STETZERiZER products more expensive than their North American counterparts?

There are several reasons why international STETZERiZER products may be more costly than our North American line. The following items, as well as others, must be factored into international retail prices:

  • shipping – which can be more than $1 USD per filter,
  • insurance,
  • taxes – such as VAT or GST,
  • duty,
  • and import fees – which can be quite costly as well.

And these are just some of the costs associated with supplying our distributors so they have products to sell to their customers.  Many international STETZERiZER models incur additional manufacturing costs that increase retail pricing as well.

  • Injections molds (to create the filter housing) for example, can cost as much as $85,000 USD each.
  • Plug inserts for the varying electrical distribution systems add cost. This cost is increased further if a filter model is equipped with a plug-through.
  • Each product line is subject to rigorous testing by, and carries a mark of approval from, independent testing laboratories recognized in the specific region or country where the products will be used.

Lastly, retail prices for our international products should not be compared to prices for our North American products on a per product basis. For example, the retail price of a single European STETZERiZER Filter is higher than its North American counterpart. However, the European filter is approximately 1.5 times stronger than the North American filter.

It takes about 20 North American filters to effectively clean up the average North American home. The same home in Europe would only require about 15 European filters. Therefore, the net cost of cleaning up a home in Europe should not be any more expensive than in North America if it were not for all the taxes and other required fees.