Electric air purifiers have become a common sight in many homes over the last 10 years. People who own air purifiers swear by their efficiency and the benefits they reap from their use. If you have certain kinds of allergies and live in a newer home, an air purifier may be a smart investment for your comfort and health. Pronto’s Buying Guide takes the guesswork out of choosing one so everyone’s breathing easier.
Air purifiers can assist in removing dust, smoke, pollen, and animal dander from the air, but they’re no substitute for regular cleaning and eliminating the source of irritants.
HEPA air purifiers are best at cleaning pollen, dust, and animal dander. Ionic air purifiers are best for removing smoke but produce small amounts of ozone. Ozone emitters neutralize strong odors but can produce dangerous levels of ozone. UV air purifiers kill microbes and bacteria, but they do not remove airborne irritants.
When comparing air purifiers, include the cost and frequency of filter replacement over a period of three to five years.
Find the square footage of the room where you will use the air purifier by multiplying the room’s length by its width. Multiply the CADR rating for smoke by 1.55 to determine an air purifier’s output. For the best results, choose an air purifier rated for a larger space than the actual room size.
Compare air purifiers based on ratings from independent organizations, such as the Association of Home Appliance Manufacturers. Don’t be swayed by seals of approval or endorsements from advocacy groups.
Clean Air Delivery Rate, a measurement of efficiency at removing smoke, dust, and pollen, assigned by the independent testers at the Association of Home Appliance Manufacturers and found on most air purifiers.
Cubic Feet per Minute, a measurement of the output of a fan in an air purifier. CFM does not measure efficiency as clearly as CADR, and the maximum CADR of an air purifier will be a little less than its maximum CFM, depending on the type of filters used.
An air purifier that removes airborne particles by changing their electrical charge, causing them to collect on solid surfaces. These air purifiers are good at removing smoke from the air.
High Efficiency Air Particulate Filters are designed to remove tiny particles from the air. HEPA filter air purifiers are the most efficient at cleaning dust and pollen. The filters must be replaced periodically.
Another name given to electrostatic air purifiers, which create negatively charged ions as well as ozone as part of the air-charging process.
An air purifier that removes strong odors by producing large amounts of ozone gas. These air purifiers do not remove airborne irritants and the amounts of ozone they generate can be dangerous to asthmatics and those with respiratory conditions.
An air purifier that uses ultraviolet (UV) light to kill airborne bacteria and microbes. These air purifiers do not remove airborne irritants such as dust, smoke, and pollen, and they tend to be of little use in the home.
An air purifier can be a good choice especially if you live in a home that was built within the last 25 years. To meet energy use requirements, newer homes are more insulated and airtight than homes built before 1985. Fresh air won’t get in unless you open a window, which can be impractical. An air purifier will remove most airborne particles.
The best air purifiers can clear the air of particles larger than three microns. These air purifiers will eliminate dust, pollen, the visible particles in cigarette smoke, and animal dander. Air purifiers are not a solution to these problems, only a partial remedy. If you want a smoke or dander-free home, you’ll need to send the smokers and pets outside.
We’d all love to breathe cleaner air, and an air purifier can reduce the number of airborne irritants in the home. If you have seasonal or animal allergies, research suggests that an air purifier can make you more comfortable. For healthy people without allergies, an air purifier probably won’t give you any health benefits beyond the good feeling you have keeping an air purifier around.
There are three basic methods that air purifiers use.
HEPA filters—These air purifiers draw air through a filter that traps airborne particles. The efficiency of a HEPA air purifier depends on the strength of its fan and the quality of its filters. The best HEPA air purifiers have powerful fans that can be too noisy for use in a bedroom.
Air ionizers—Air purifiers like the popular Sharper Image Ionic Breeze change the electric charge of air particles which causes them to collect on the purifier’s specialty surface. Ideally, the particles collect on metal plates inside the air purifier. In practice, the particles collect inside the air purifier but can also escpe to walls, floors, and furniture, which can be a burden if you don’t like vacuuming. These air purifiers generate small amounts of ozone, which can be a concern.
Ozone emitters—These air purifiers simply produce ozone. They don’t remove particles from the air, but they do neutralize odors from smoke and mildew. As with ionic air purifiers, the ozone can be a health concern. While there is no expert consensus on health effects, both the EPA and the American Lung Association recommend avoiding air purifiers that produce ozone, particularly if you have asthma or a respiratory condition. The EPA mandates that room ozone levels should be less than 50 parts per billion.
UV emitters—Ultraviolet light air purifiers do not remove airborne particles. These specialized air purifiers kill microbes and bacteria and offer limited real usefulness in a home setting.
When choosing an air purifier, first consider your needs. If pollen and pet dander control are important, look for a HEPA air purifier. If you need to reduce odors or cigarette smoke, an ionic or ozone-emitting air purifier will work.
Next, think about the size and layout of the room where you’ll be using the air purifier. For a small office or bedroom, a fanless air purifier may be sufficient. For a large, open living room, you may need more than one air purifier to notice a difference.
Finally, think about fan noise, ozone emission, and lifetime ownership costs. When comparing air purifiers, include the cost and frequency of filter replacement for three to five years to determine the lifetime cost of ownership.
All air purifiers are rated for the amount of air they can clean. The Association of Home Appliance Manufacturers assigns a Clean Air Delivery Rate, or CADR, to al the air purifiers it tests. This number tells you how much clean air an air purifier can create per minute, based on a room with an eight-foot ceiling.
CADR is rated for dust, pollen, and smoke. On the specs, look for three CADR measurements; pollen, smoke and dust. The CADR indicates volume of filtered air delivered by an air cleaner. The higher the tobacco smoke, pollen and dust numbers, the faster the unit filters the air.
Since smoke is the toughest to clean, the easiest way to match an air purifier to a room is to multiply the CADR rating for smoke by 1.55. This will give you a rough idea of how much square footage an air purifier can clean efficiently (square footage = room length multiplied by width). Example: if you see a smoke rating CADR of 200, multiply 200x1.55=310. So a CADR of 200 will cover a room that’s 15x20, or 300 square feet. Still confused? Most manufacturers list square foot capacity if you don’t feel like double checking their math.
Air purifiers with fans may have a cubic feet per minute (CFM) rating instead of a CADR. Since an air purifier can only clean the air that it can circulate, this number gives you a general sense of its CADR, although the CADR performance of the air purifier will be a bit lower than its top CFM.
Still obsessed about CADR? Check out http://www.cadr.org/consumer/index.html for more info about how it works and pretty pictures of what pristine air looks like.
Electrostatic air purifiers made by Oreck and The Sharper Image have outsold all other models despite the poor ratings they have received from Consumer Reports. These fanless air purifiers are quiet and have a low lifetime cost because they use metal collection plates that can be cleaned, eliminating the expense of filter replacement.
In 2003, following a string of poor reviews for its air purifiers, The Sharper Image sued Consumer Reports on the grounds that its testing results were wrong. The courts sided with Consumer Reports, and The Sharper Image has since sought out approval from private organizations such as The Asthma and Allergy Foundation of America.
When you’re comparing air purifiers, beware of these endorsements from advocacy groups. Look for air purifiers rated and tested by independent organizations, such as the Association of Home Appliance Manufacturers, and try to find an affordable air purifier that will meet your unique needs.
We've compiled this group of information links to help you further your research: