Americans spend 90 percent of their time inside, where air typically contains two to five times more pollutants than the outdoors, according to the U.S. Environmental Protection Agency (EPA). Because of all our indoor air quality problems, the EPA ranks indoor air pollution as a high-priority public health risk.
For the purposes of this guide, we looked at portable air purifiers, which can move from room to room. Consumer Reports (CR) has found them more effective than whole-house filters for an individual room or rooms, particularly if your house doesn’t have forced air heating or cooling. Furthermore, they’re the only air purifiers rated by Energy Star (see below).
What To Look For
Type of Filter
Portable room air cleaners trap particles in either a high-efficiency particulate air (HEPA) filter, or, for electrostatic models, electrically charged metal collector plates. HEPA filters must be replaced over time, while electrostatic filters are washable. Furthermore, electrostatic filters do produce some ozone as a by-product, and high ozone levels can exacerbate respiratory problems.
Some models also contain carbon filters to eliminate odors, reduce humidity and filter larger particles, but “carbon filters have not been very effective in our tests,” CR says. Finally, ionizing air purifiers clean the air by releasing ions into the room, but again, these have been found less effective in product tests than HEPA filters and may produce ozone.
Energy Star Rating
Energy Star rates air purifiers based on their “Clean Air Delivery Rate” (CADR) a measurement established by the Association of Home Appliance Manufactures. The CADR measures the removal of dust, pollen and tobacco smoke and represents the number of cubic feet of clean air a unit delivers each minute. Each purifier must remove dust at a rate of 2.0 square feet of air per watt of power used. Also, all Energy Star-rated purifiers, regardless of filter type, must meet the UL requirement for ozone (50 ppb).
You want to be sure you buy a purifier that’s suitably sized to your room. A machine that’s too large will pose a drain on your energy bill, while one that’s too small won’t be effective.
Annual Filter Replacement Costs
Operating costs carry just as much weight as upfront costs when it comes to affordability. Whether purchasing one of the models on our Product Comparison page or one of your own personal choice, be sure to ask about replacement filter costs.
Shopping & Usage Tips
In some systems, filters are treated with antimicrobials. Since these chemicals are often undisclosed by the manufacturer, it’s best to replace antimicrobial-treated filters with untreated ones.
Consumer Reports’ testing has found that portable air purifiers set on low clean just as well as they do when set on high. Choosing the low setting helps to save on your energy bill.
Clean reusable filters, or replace disposable ones, as directed by the manufacture to ensure optimal performance.
Air Purifiers to Avoid: Ozone Generators
Virtually all electronic appliances emit very low levels of ozone as a by-product, but some purifiers emit large amounts of ozone intentionally as a way of cleaning the air. Some air purifiers have been found to elevate indoor ozone to levels to 20 times the federal health limit of 50 ppb. California recently banned the use of ozone generators, and the EPA states that “At concentrations that do not exceed public health standards, ozone is generally ineffective in controlling indoor air pollution.”
The Best Air Purifier: Proper Home Maintenance
In addition to their steep purchase price ($200-500 on average), air purifiers can raise energy bills as much as $200 for certain models, although the best models average close to $60. Proper cleaning and maintenance are free and often more effective.
-Eliminate smoking indoors.
-Keep your house ventilated by opening windows (when outdoor air quality is acceptable) and using ceiling or box fans.
-Damp-wipe surfaces and vacuum regularly (optimally with a HEPA filter-equipped vacuum).
-For those with asthma or allergies, carpets–which trap dust, pesticides and other pollutants–may need to be removed entirely and replaced with washable area rugs.
-Wash bedding and curtains in hot water to kill dust mites.
-Use a dehumidifier if mold is a problem (most air purifiers don’t reduce humidity).
-Switch to eco-friendly cleaners, less-toxic pesticides and other low-VOC paints and sealants to reduce exposure to formaldehyde and other chemical indoor-air contaminants.
-If you live in an apartment, cut down on secondhand smoke or other odors from neighbors by caulking baseboard cracks, using clear silicone sealant on floorboard cracks, and duct-taping holes around radiators.
-Keep up the maintenance on appliances that run off of natural gas, such as water heaters, gas stoves and gas fireplaces, to decrease exposure to carbon monoxide and nitrogen oxides.
Even if you purchase an air purifier, continue to practice proper source control and ventilation; air purifiers don’t entirely eliminate gases or household chemicals.