Conscious Choice: Air Cleaners

November 2000 | Sensible Home

Air Cleaners

by James Dulley

Dear Jim: We have an airtight efficient house and we might need some room air cleaners in addition to our furnace air cleaner. I’d like to know whether room air cleaners help allergy and dust problems and which ones are most efficient. — Beth D.

Dear Beth: Although a central furnace-mounted air cleaner certainly helps, using several additional room air cleaners will remove many more particles and allergens from the air. I have an efficient electrostatic furnace air cleaner plus I use two smaller ones in my bedroom and study where I write.

If you have allergies, you know it from the symptoms. People without allergies may also suffer health hazards from poor indoor air and not be aware of it. According to the EPA, indoor air quality in an efficient, airtight house may be worse and more hazardous than outdoor air with smog.

Many of the particles that cause allergies (mold, dust mites, pollen, dander, etc.) are relatively large particles. These larger particles puff up when you sit on a sofa, for example, and you breathe them in. These larger particles settle back down again too quickly to be drawn into the furnace air return, so the central furnace filter does not get a chance to remove them. A properly sized room air cleaner will remove them quickly so that next time you sit on the sofa, fewer particles will puff up.

The two most effective room air cleaners are "true" HEPA (high-efficiency particulate air) and electrostatic (electronic) designs. You will find hundreds of low-quality room units available; many are not effective. Be careful when selecting and avoid models that feature terms such as "HEPA-like" on the packaging.

A HEPA filter works by forcing the room air through a dense filter media. To be a true HEPA, it must remove 99.97 percent of all particles down to .3 microns in size. These models require a powerful fan to force the air through the filter, so they use a little more electricity than electrostatic models.

Electrostatic models have plates inside that electrically charge the particles. This makes them stick to collector plates with an opposite charge to remove them from the air. Every month, slip out the collector assembly and rinse off the dust, smoke, and allergen particles.

Select a model with several fan speeds, especially if you plan to use it in a bedroom at night. Ones with a charcoal after-filter will also remove odors and some volatile chemicals. The heaviest charcoal filters are best.

CADR (clean air delivery rating) is a good method to select a room air cleaner. Each model is tested to determine how well it removes smoke, pollen, and dust. This rating (often shown on the packaging) helps you determine which model is best for rooms of various sizes.

Write for (or instantly download) Update Bulletin No. 885, buyer’s guide of fifteen manufacturers of effective room air cleaners listing types, speeds, recommended room sizes, features, prices, CADRs and an allergen size chart. Please include $3 and a business-size SASE. James Dulley, Conscious Choice, 6906 Royalgreen Dr., Cincinnati, OH 45244.

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