Hidden away in your basement or attic, your HVAC system needs an air filter to keep your central air conditioner (and furnace) humming along by protecting the mechanicals from dust and debris. The best filters also trap indoor pollutants, such as dust, pet dander, and pollen, helping to clean the air in your home.
Consumer Reports conducted several tests in in these tests, they gauge how will an air filter removes pollutants from the air and how freely air flows through the filter at all fan speeds.
“Thinker filters - those that are 4 or 5 inches - perform better in our tests, and we found that you don’t have to replace them as often” says Dave Trezza, who oversees Consumer Reports air filter tests. But not every HVAC system can accommodate that thickness; The most common size is 1 inch thick. If that is the size you need, the Filtrete 1900 model is your best bet. Steer clear of the Filtrete 600 Dust & Pollen ($9 price) which got poor overall score.
As you shop, pay attention to the filtering grade given by the manufacture. The most commonly used system applies a MERV number (Minimum Efficiency Reporting Value) to each filter. But 3M and Home Depot have each developed their own systems, called MPR (Microparticle Performance Rating) and FPR (Filter Performance Rating), respectively. No matter the grading system the higher the number, the better the filter should be at getting rid of air pollutants.