Air filters

“What kind of air filter should I buy for my allergy?” The answer is “it depends on what you’re allergic to.”

If you are allergic to cat dander or grass pollen, we recommend investing in an advanced filter. These allergens are small; thus, they are lighter than air and stay airborne long enough to be filtered out of the air. Compare that to dust mite allergy, which is relatively large, staying airborne for only 15 to 20 minutes after being disturbed (such as making the bed). There’s no way a filter can catch much dust mite allergen once it has settled back onto the bed or carpet.

Electrostatic filters are interesting. You get a permanent metal filter taking the place of your disposable fiberglass filter. This metal filter is better at trapping allergens than less expensive fiberglass models. If you use an electrostatic, run your air conditioning system using “ON” rather than “AUTO”. You just paid for a good filter, and you want it filtering 24/7, not just when the compressor or furnace turns on. Be sure to clean the filter regularly with a strong flow of water at least once or twice a month. If you don’t keep an electrostatic filter clean, it will become less effective, increasing the drag on your entire HVAC system. Many HVAC companies don’t like electrostatic filters at all, saying they reduce the life of the entire system. Instead, they recommend disposable 3M Filtretes.

If you get a free-standing filter, should you go HEPA filter or a Sharper Image Ionic Breeze? This depends somewhat on budget and noise tolerance. The HEPA filters have fans that make some noise. You have to change the pre-filter every two or three months. It’s very easy to change, but take the unit outside before you disassemble it so the dust doesn’t make a mess inside. Changing the main filter is almost as easy, and it only has to be done every couple of years. Post-bankruptcy, Sharper Image stills sells the Ionic Breeze, and Consumer Reports still recommends you don’t buy them. Here’s a line from their article: “By that logic, my coffee table is also an air filter because it collects dust.” Look at a store’s return policy to see if you can try the filter out first. You can usually return them before 30 or 60 days. Keep all the packing materials and your receipt.

No matter what filter you buy, remember that a filter is just one step in a long process of allergen avoidance. If recommended by your doctor, you should also cover your mattress and pillow with impermeable covers, wash sheets in hot water, remove carpet from your bedroom, and keep the humidity in your home low enough to reduce growth of dust mites and mold.

No one nose allergies like we do.™

Note: Information contained in this article should not be considered a substitute for consultation with a board-certified allergist to address individual medical needs.


David B. Engler, MD, FACAAI, FAAAAI Dr. Engler is a board-certified allergist and immunologist who hails from Houston, Texas. He was recently voted Best Allergist/Immunologist in Houston by H Texas Magazine, an honor based on peer and reader voting, as well as a Super Doctor by Texas Monthly Magazine.

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