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Is It Necessary For You To Buy An Air Purifier?

If you suffer from allergies or want to reduce odors in your home, a room air purifier might be the solution. Room air purifiers can eliminate the tiniest dust, bacteria, mold, viruses, pollen and smoke in the surrounding area. Shop for an air purifier based on the technology it uses to clean the air, its initial cost and the cost of replacement filters, the unit’s noise level, the size of the room and the unit’s clean air delivery rate (CADR). CADR is a measure of how much clean air the unit can deliver in cubic feet per minute (cfm) for each type of contaminant. For example, a purifier sized to fit a 210-sq.-ft. room may have a CADR rate of 155/133/155 for dust/smoke/pollen, while a unit for a 340-sq.-ft. room may have a 231/220/245 rating. Bigger is better as long as you can live with the higher noise level of a larger unit. Some models also remove odors. If that’s a concern, shop for a unit that lists odor removal as a feature. Room air purifiers vary widely in price, from as low as $39 to as much as $600. The cheaper units won’t have much effect on your allergies; expect to pay $200 to $400 for one that does.

Three common room air purifier technologies…


True HEPA air purifiers work by filtering out the airborne contaminants using a True HEPA filter that captures at least 99.97 percent of particles .3 microns in size. True HEPA filters are effective at removing pollen, dust, dander and some larger bacteria from the air. Sizing the unit to the room is critical because an undersize unit will clog quickly. Also, be wary of air purifiers that use filter terms like HEPA, HEPA type or ultra HEPA. Those filters may remove 99.97 percent of larger airborne particles like pollen, but if they don’t filter down to .3 microns, they won’t perform like a True HEPA unit. An effective True HEPA unit costs about $200. The downside to filtration-type air purifiers is the ongoing filter replacement cost, which can run about $250 per year.

Negative Ion

Negative ion air purifiers work by giving airborne particles a negative charge so the particles migrate and cling to positively charged walls, ceilings and floors. Negative ion units are controversial because they don’t actually kill bacteria, viruses and mold, or filter them out of the room. They just get the particles out of the air and make them cling to room surfaces. You have to remove the particles with a True HEPA vacuum. In addition, some negative ion models generate ozone—a lung irritant. According to the EPA, ozone can also react with household cleaning products to create harmful byproducts in your home.

Positive/Negative Ion

Positive/negative ion air purifiers produce both positive and negative ions, which attach to germs, fungus, viruses, bacteria and mold and kill them by removing hydrogen from the particle’s surface proteins. Some of these units also include a True HEPA filter and an activated carbon filter to remove odors. Ion-style air purifiers cost $200 to $600.

Before You Make A Purchase…

Think of an air purifier as your last line of defense against allergens and odors, not your first. Before you buy one, consider taking these steps to cleaner air:

  • Install a MERV 11 furnace filter.
  • Stop burning candles and reduce the number of wood fires, as well as ban smoking in your home.
  • Clean dryer ducts at least twice a year and run bath and kitchen fans longer to exhaust more dust, humidity, odors and grease and reduce mold formation.
  • Run your air conditioning with a MERV 11 air filter during pollen season and close all windows.
  • Reduce the amount of carpeting in your home, and vacuum more often with a True HEPA filter vacuum cleaner.
  • Remove shoes at the front door.