When it comes to discussing the benefits of room air purifiers, manufacturers are pointing to higher test scores as a reason for consumers to be excited. You should temper any excitement, however, so you can understand what these scores mean and whether a high score is of any consequence to the room you that want to clean.
Consumers who are in the market for an air purifier will find that prices for the majority of models increased by up to 10 percent over the past 3 years. “The raw materials in the construction of the units have gone up, such as copper and carbon,” says Michael Domon of Austin Air, which makes air purifiers. He says his company’s models jumped in price by about $30 on average. He says carbon, which is used in air-purifier filters, is becoming more expensive because of its use in a wider range of products.
HIGH SCORES. Association of Home Appliance Manufacturers (AHAM), which is a trade association, says room air purifiers are becoming more effective.
AHAM performs tests to determine whether the appliances live up to manufacturers’ claims, and it says more room air purifiers log higher scores for clean air delivery rate (CADR) than ever before. (CADR is AHAM’s measurement for the volume of filtered air that’s delivered into the room by an air purifier. The higher that the CADR score is, the faster that allergens, such as dust, pollen and tobacco smoke, will be filtered from the air.) (Whole-house air purifiers are rated on their minimum efficiency reporting value, or MERV, by American Society of Heating, Refrigerating and Air Conditioning Engineers.)
Wayne Morris, who is an AHAM technical expert, tells Consumers Digest that CADR scores rise every year. He says his association now sees more models that have a CADR score of as high as 450, which is the maximum score that AHAM’s test registers. Morris says that 3 years ago, only one model had a CADR score of 450. Today, at least seven do because of what he calls improvements in the air purifiers’ motor and the design of the fan blades to move the air throughout a room more efficiently.
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The higher score also means a higher price for an air purifier. For example, the Blueair 603, which has a CADR score of 450, costs $800. The otherwise identical Blueair 503, which has a CADR score of 375, costs $700. According to our research, this is a representative increase between purifiers that have a CADR score of 450 and those that have a score that’s in the 300s.
However, an air purifier that has a higher CADR score isn’t necessarily the best choice for the room that you’re trying to clean. According to AHAM, a good rule of thumb is to look for an air purifier that has a CADR score that’s equivalent to two-thirds the size of your room’s area. For example, a 10-by-12-foot room—120 square feet—would call for an air purifier that has a CADR score of at least 80. (See “Calculating Your CADR Score.”) An air purifier that has a CADR score of 450, then, would be appropriate for a room that measures nearly 26 feet by 26 feet.
Richard Shaughnessy, who is the director of indoor air quality at University of Tulsa, says AHAM’s rule of thumb includes caveats. He says CADR scores are based on the initial operation of the appliance. He says, on average, air purifiers can become up to 50 percent less efficient in only 6 months’ time. CADR scores also are based on an air purifier operating at its highest setting. Most consumers typically use the devices at lower settings to limit noise or the amount of air movement in a room, he says, which makes it proportionally less efficient. For example, he says that if you operate an air purifier at half power, you should expect a CADR that’s reduced by roughly 50 percent from its advertised score. So if you plan to operate your air purifier at a lower setting, you might want to consider a score that’s higher than AHAM’s recommendation for the corresponding room size.