Compare Room Air Purifiers

Look for the room air purifier's CADR, or clean air delivery rate. This number should be at least 100, but a rate of over 350 means that the air purifier is excellent at cleaning the air, according to Consumer Reports. You'll find the biggest selection from brand names such as Honeywell and Holmes when it comes to various CADR options, since these two companies offer and sell the most air purifiers.

Pay attention to the type of filter inside the room air purifiers you're comparing. Those with a HEPA (high efficiency particulate air) filter will be able to remove air contaminants more efficiently that those that do not. HEPA filters are more successful at achieving this because they can trap particles that are small enough to travel right through other filters. Brands such as Blueair and Whirlpool, among others, provide air purifier options that include HEPA filters.

Compare the weight of the purifiers you are considering. Most will be between 10 and 20 pounds. It's important that you're able to lift it up easily if you plan to take it from room to room or up and down stairs. However, keep in mind that the large units often have a larger filter than can remove more particles from the air.

Look for a model that has wheels if it weighs 20 pounds or more. Wheels make it easier to move from room to room.

Research the available features. A fan, for example, will improve the performance of an air purifier. Another feature that is sometimes included is a UV lamp designed to get rid of germs, which can be found in certain Germ Guardian products. Also, a service indicator can let you know when the room air purifier needs to be cleaned or repaired, and a dirt sensor helps to regulate the air purifier without your intervention.