Do you really need an air purifier?

For a lot of folks, air pollution is synonymous with belching smokestacks and smog-filled skies. But pollutants found right under your roof, including mold spores, dust mites, and even carbon monoxide, are often the bigger problen. Consumer Reports' latest tests of more than 40 air purifiers yielded a handful of winners that could help clear the air.  

Before you make the investment, follow our advice for improving indoor air quality through enhanced ventilation, better moisture management, and the control of source contaminants in your home. If, after all that, you or others in your home are still suffering from allergies, asthma, headaches, or the like, look for an air purifier that excelled in our tough tests, in which we fill a room with smoke and dust and let the machines prove their cleaning power.

If your home has a forced-air heating or cooling system, consider a whole-house purifier, which is a basically a super filter that replaces the standard filter inside your furnace. Installing a 1-inch-thick filter, such as the $20 3M Filtrete 1900 MPR, can be an easy, inexpensive do-it-yourself project. Thicker purifiers, including the top-rated Lennox Healthy Climate CarbonClean 16, $100, require professional installation, adding a couple hundred bucks to their initial cost.   

Portable room air purifiers, which typically weigh between 10 and 20 pounds, are designed to clean a single area of your home. Larger models, including our top-scoring Honeywell HPA300, $250, tend to capture the most airborne particulates in our tests at both high and low speeds because of the increased surface area of their filters.  

As you sift through our air purifier Ratings, remember that you'll have to routinely replace the filter on your air purifier. This expense is reflected in our annual cost and could be the difference of $100 or more in your pocket each year.

—Daniel DiClerico (@dandiclerico on Twitter)