Do Electrostatic Filters Work?


Has anyone used an electrostatic air filter? We are thinking of purchasing one due to the dust in the house and would like to know if anyone has any comments about them or can mention any things to be on the look out for.
Thank you.
Lisa P.
Air Quality Expert's Advice

Electrostatic filters work by charging the dust particles in the air which is supposed to attract them to metal plates in the machine. The trouble is these charged dust particles are also attracted to all the surfaces of your home, causing what's called "deposition," black markings on the walls. Some of these machines also produce ozone which is a chemical that oxidizes the surfaces of your home and is very harmful to breathe. The third problem with these machines is that they do not work well. The best dust removal strategy is to switch to a central vacuum system that vents outdoors. Your conventional vacuums leak a lot of unseen dust whenever you use them. Another is to change from carpeting to hard surface flooring, which can easily be damp mopped to trap the dust. An air filter can help, but it is better and cheaper to solve the problem, rather than covering it up. If you must choose an air filter, look at the percent efficiency of filtration and the amount of air filtered per minute. The higher these two ratings, the better.
Richard C. MacC.
Home Planner
Specializing in Indoor Air Quality
Service Tech Says "Yes"

I am a service technician for a heating & a/c company and am a strong advocate of electrostatic air cleaners. They are nearly as effective and much more economical than the electronic 'zapper' type air cleaners. I have tried both the disposable (3M's Filtrete with the red label) and the permanent (Newtron, DustFree, and others)in my own home and have been generally pleased with the results.

The 3M Filtrete seemed to perform better (at $13 a pop, it had better!) than most of the permanent ones. The 'cut-to-your-size' ones available at the home center are OK but don't last nearly as long as the made-to-order ones. They also tended to fall apart during the monthly cleanings. I've found that metal-frame filters made by DustFree are very durable, effective, and moderately priced. (Expect to pay your HVAC company about $70-$90 for this one.) The Newtron filters have better-looking literature but weren't as durable. Most have molded plastic frames. They claim a 'lifetime warranty' and retail here for $125+. There are many other brands of varying quality and price.

I and my oldest son have allergy problems and both noticed a tremendous decrease in symptoms after only a couple weeks' use. Remember, though, these air cleaners only work when your furnace or a/c fan is running and they can't be expected to 'clean the house' for you. Don't expect them to pick up all the dust in the house. Some dust particles are too heavy to become entrained in the air stream. These may deposit themselves above a door or against a cool window.

Also, beware of burning those pretty-smelling candles! Many contain petroleum as a main component. You'll find your filter turning black as the waxy particles begin to clog your air cleaner and attract more dirt. IF it continues long enough, it could ruin the cleaner. I have seen homes blackened with residue from candles so severely that it looked like damage from a house fire.

The electrostatic filter must be cleaned regularly. The dirt will deposit on the filter's interior so it may not look too dirty, but wash it anyway. Spray some household cleaner like 409 or Fantastik (we use Spray 9 at work) onto both sides of the filter and let it sit a few minutes. Then rinse it gently. Do not use a strong stream like from a garden hose. You may break the tiny nylon rods inside the casing with the powerful water stream. Once all suds have been rinsed out, allow it to drip-dry. Reinstall it, paying close attention to the arrow indicating air direction. (The arrow should point TOWARD the furnace or a/c.) Putting it in damp will not ruin it, but it works better when it's dry. As a result of my 'test-drive', I have sold many of these to many happy customers!
Ron S. in Millsboro, DE
Consumer Likes Cheap Throw-Aways

We have found that electrostatic filters are no better than the regular cheap ones that you can buy for 79 cents a piece. We live near the airport, and needless to say--we get dust all year round!! The electrostatic filters are nice--until you have to clean them! There are about 8 layers to them, and to really get them clean--you have to take them apart layer by layer and hose them down -- making sure you put them back together exactly as they came, and believe me, it's hard--because they snag and catch on everything in between! I end up cleaning them and my husband ends up putting them back together!! I'm going back to the "throw-aways"! PLUS....there's a new spray out that you can spray on the "throw-aways" called "Dust Catcher" it's an adhesive spray that's supposed to really grab and hold the dust! You CANNOT use these sprays on electrostatic filters!! You decide!!
Lynda E.
Use High Quality Filters Instead

We bought one of the famous and very expensive Allergy Free air filters almost 4 years ago. We thought it would be helpful with our daughters breathing problems. Wrongo! It did not help with the dust in our 70 year old home and was not worth the money we spent. At that time they sold for around 60 dollars, now I hear them advertised as 120 dollars! Way to much for an air filter we found ineffective.

What we have found that does a better job is the 3M Filtrete filters. They usually cost around 10-12 dollars a filter. We have found them for $ dollars a piece at the end of the season as our local warehouse food store. I bought about 12 at $4 for a huge savings.

The recommendation is to change them every 90 days. We find this is too long and we usually change our filter during the winter every 45 days and about every 60 days during the times when we have less air flow through our furnace.
Joan E.
A Cautionary Note

I had an electrostatic filter and it did not allow enough air flow over the unit and I burned the motor. I now use a triple pleated filter and spray the back side with a special spray to make it sticky and it catches the last few microns of dust. I buy the spray at a refrigeration shop and it is called "filter coat".
Rita S.
Serviceman Sees Troubles

I am Heating/Cooling serviceman and I have found that the electrostatic filter is too dense for most home furnace applications. I find that they interfere too much with the air flow of the furnace and this causes the air conditioner to freeze up in summer and sometimes it can even cause the furnace to cycle on its high limit safety control when heating in the winter. Another problem with them is that they require dedicated maintenance and should be cleaned way more often than a disposable filter.

For the best value, I would recommend a good Electronic Air Cleaner or a real good system is the Lifesbreath 1000 which can clean the air in your house (up to 95% of air born particles) 3 times a day. These 2 systems cost considerably more than just the filter but are a way better value.
C. E. in Whitla A.B., Canada
Pleased With Honeywell Unit

We had one installed when we had central air-conditioning installed a number of years ago. It is a Honeywell unit. We can't be too pleased with it's performance. When it is used--during the summer months all the time, & partially in the winter as the heat in our house is hot water baseboard, we have found that we just don't have to dust at all. When it is running there is no pollen ever (my wife has hay fever & isn't bothered at all in the house since we got the unit). I clean the electrostatic elements & the washable filters about once a month during the summer--takes about an hour totally-& that's all the maintenance I've ever done. I recommend the installation of such a unit in a central system.