What are EMF and EMI?

If you would like additional help determining your filter needs, please contact Greenwave at [email protected] or 1-800-506-6098.

How many Greenwave filters do I need?

Many people ask us whether they will need a filter for every electrical outlet in their environment. In most cases the answer is NO.

The general guidelines below can help you calculate the number of Greenwave filters you will need for your environment. If you would like additional help determining your filter needs, please contact Greenwave at [email protected] or 1-800-506-6098.


Most rooms within homes typically require 1 to 4 filters to reduce dirty electricity to acceptable levels. Two Greenwave filters are usually needed to reduce dirty electricity within average-sized rooms (e.g., bedroom, dining room). Rooms with heavy concentrations of electronics (e.g., media room, kitchen, home office) may require more than two filters (3-4), while smaller rooms, such as bathrooms, usually require only one.

The CHART below provides additional information about the number of Greenwave filters typically recommended for most rooms within homes (e.g., houses, apartments, condos).

Type of Room Number of Filters Typically Needed
Kitchen, Family Room, Living Room, Media Room, Home Office 3 – 4 filters (each)
Bedroom, Dining Room, Laundry Room, 2 filters (each)
Bathroom, Walk-In Closet 1 filter (each)
Basement, Garage, Tool Shed, Workshop 1 – 2 filters (for every 150 square feet)



2 to 3 filters for every 100 square feet


5 filters per classroom

How do I install Greenwave filters?

Greenwave filters are easy to install. Simply plug them into electrical outlets to start reducing dirty electricity immediately.

For best results, the filters should be installed as close as possible to devices known to generate dirty electricity (e.g., electronic equipment, fluorescent lighting, light dimmer switches, SMART meters, appliances/devices with internal motors).

In addition, we recommend using Greenwave’s Broadband EMI Meter to guide filter installation. This meter can help you identify significant sources of dirty electricity in your environment and determine the best number of Greenwave filters to install in each room for optimal results. It can also show you how much dirty electricity the filters are eliminating. The meter displays “BEFORE filter” and “AFTER filter” EMI measurements (in  millivolts) on the same screen simultaneously. The “AFTER filter” display screen also shows the percent reduction in local “electrical noise density.”

Click the links below for more detailed instructions for using Greenwave’s dirty electricity filters and meter.



Can Greenwave filters be plugged into power strips?

Yes, as long as there is sufficient space.

What is the difference between Greenwave filters and Graham-Stetzer (Stetzerizer) filters?

Both types of plug-in filters reduce the level of dirty electricity present on the wiring in buildings. Overall, Greenwave filters offer more features than Stetzerizer filters. Most of our filter models include a built-in outlet at their base for plug-through convenience and are both safety certified and RoHS compliant.



I plugged a filter into an outlet and it started to buzz. Is there a problem?

This usually means the filter is overloaded. In other words, there is more dirty electricity on nearby wiring than the filter can reduce sufficiently on its own. This problem can usually be resolved by installing another filter in the same outlet (using a power strip or electrical tee) or 1 to 2 filters in nearby outlets or power strips.

If the buzzing doesn’t stop after installing additional filters, contact Greenwave.

I saw a small spark and hear a popping sound as I plugged in a Greenwave filter. Is something wrong?

NO, this often happens as electrical energy “loads into” the capacitor technology used by the filters. It is not dangerous to you or your Greenwave filters. Our filters undergo rigorous safety testing and are safety certified.