The STETZERiZER filter is based upon 100 year-old science and power engineering principles. Newly introduced is the design, which is focused on the needs of the customers in homes, offices, schools, etc. Filters have been extensively applied for decades by industrial users and the electric utility industry itself. The STETZERiZER filter is designed to filter harmonics and other high frequency current (trash) from the electrical environment, thereby reducing the potential for leakage into the human environment and creating additional trash in non-liner loads (televisions, computers, variable frequency drives, energy-efficient lighting, etc.).
The high frequency current (call many names such as dirty power, electrical polution, noise, harmonics, trash, hash, transients, etc) on the neutral wire in the electrical system is positioned to return directly to the power system via the feeder neutral to the substation, and possibly beyond. However, as is often the case, the utility feeder neutral is not adequately sized (as required by law). If this is the case, much of the return current will flow through the ground rather than the feeder neutral. Under these conditions, the STETZERiZER filters still provide benefits, but utility companies should be taking the necessary steps for public safety by updating power lines, providing larger, higher-strand neutral returns to handle the high frequencies.
At 60 Hz the filters act as capacitors and normally improve the power factor of the customer load, which are normally slightly inductive.
Matt's Thoughts: These are incredible to use for travel alone, but they are a must if you live in an apartment complex or in a dense neighborhood with a lot of electronics plugged into the grid. I do not recommend using these if you're fully off grid.