Best Air Filters for Your Central AC and Furnace
Clean the air in your home and protect your HVAC system with one of these top-performing filters from CR’s tests
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Hidden away in your basement or attic, the air filter in your HVAC system is something you probably don’t think about much. But a good air filter keeps your central air conditioner (and furnace) humming along by protecting the mechanicals from dust and debris. And the best filters trap indoor pollutants such as dust, pet dander, and pollen, helping to clean the air in your home so it’s better for you to breathe.
That’s important because the concentration of air pollutants inside your home can be two to five times higher than concentrations typically found outdoors, according to the Environmental Protection Agency. An effective, snug-fitting HVAC filter can also help filter the air inside your home when air quality outdoors is poor, the EPA says.
We gauge how well an air filter removes dust, pollen, and smoke from the air, and see how freely air flows through the filter at any fan speed. We also calculate the annual costs of replacement filters, based on the manufacturer’s recommendation for when to change them. (Keep in mind that prices may vary by retailer and that it may be cheaper if you buy filters in bulk.)
“We find that thicker filters have two big advantages: They filter particles out of the air better and require replacement less often,” says Misha Kollontai, who oversees CR’s air filter testing. But not every HVAC system can accommodate a thicker filter—the most common size is 1 inch thick—though you can retrofit the ductwork of some systems to accept one.
Something else to keep in mind as you shop is the filtering grade given by the manufacturer. The most commonly used system applies a MERV number (minimum efficiency reporting value) to each filter, which was developed by ASHRAE (formerly the American Society of Heating, Refrigerating and Air-Conditioning Engineers). But 3M and Home Depot have developed their own classification systems called MPR (microparticle performance rating) and FPR (filter performance rating), respectively. “Both types of grading assign higher values to more effective filters, so when in doubt, go with a higher rating,” Kollantai says.
Don’t have a forced air HVAC system? You can still get some relief with a DIY air cleaner. We tested this popular social-media hack in the lab. Here’s what you need to know before trying it at home.
Below are the top air filters from CR’s tests, grouped by their thickness and listed in alphabetical order. For more information on air filters, including some models to avoid, see our full air filter ratings and air filter buying guide.
CR’s take: The Filtrete 1900 Maximum Allergen Reduction filter is impressive at removing dust, pollen, and smoke from the air when the HVAC system is running on its highest fan speed, earning an Excellent rating in that test. But at the lowest speed, the filter is only average at removing those same airborne particles. Airflow through the filter remains strong in both instances. Filtrete recommends that you replace this filter four times a year, so though the price is only $20 per filter, the annual cost can run to $80.
CR’s take: In our tests, the Filtrete 2500 Smart Premium Allergen Ultra Fine Particles S-EAX22DC-6 effectively removes airborne particles with the system running on its highest fan speed, earning an Excellent rating. At the lowest speed, however, particle removal is only average. The manufacturer recommends replacing the filter four times a year, at an annual cost of around $100, though the sensor may indicate that it should be changed more—or less—often.
The relatively high price of these filters is somewhat justified by their “smart” technology. With it, you can check the status of your filter from your smartphone to see if and when it needs replacing. However, unless you’re worried about needing to replace your filter early, you can also just set a calendar reminder.
We also test two other 1-inch smart Filtrete filters, the Filtrete 1900 Smart Premium Allergen Bacteria and Virus and the Filtrete 1500 Smart Allergen Bacteria & Virus. Both have lower MPR filtering ratings than the 2500 Smart Premium.
CR’s take: The Filtrete Ultra Allergen Reduction 1500 MPR filter earns a Very Good rating for removing smoke, dust, and pollen from the air with the system running on a high fan speed, but it’s only average when running on its lowest speed. In both cases, airflow through the filter is strong. Filtrete recommends changing this filter four times a year for an annual cost of $68.
CR’s take: The 4-inch-thick Aprilaire Healthy Home 213 MERV 13 earns an Excellent rating for removing dust, smoke, and pollen when the HVAC system is running on its highest fan speed. It does almost as well when running on its lowest fan speed, and air flows freely through the filter. Annual cost is $41 per year based on Aprilaire’s recommendation to replace the filter once.
We also test the 4-inch Aprilaire Allergy & Asthma 216 filter, which earns similar scores. But you’ll pay $184 in annual costs because the filter costs more and Aprilaire recommends replacing it twice a year.
CR’s take: The 5-inch-thick Carrier EZ Flex Filter Cabinet with a filtering rating of MERV10 earns a very good rating for removing dust, pollen, and smoke from the air when a system is running on its highest fan speed, but it earns only a so-so rating with the HVAC running on the lowest speed. It has no problem maintaining airflow in either situation. Carrier recommends replacing this filter twice a year, which translates to an annual cost of $128.
CR’s take: Another good performer, the 4-inch-thick Filtrete Healthy Living Ultra Allergen 4 MPR1550 capably removes dust, pollen, and smoke with the HVAC system running on both its highest and lowest fan speeds, earning very good ratings. This filter provides nearly unrestricted airflow. Filtrete recommends that you replace this filter once a year, and at $29 per filter, that makes it one of the more economical filters in our tests.
CR’s take: The 5-inch-thick Lennox Healthy Climate CarbonClean 16 effectively filters dust, smoke, and pollen when the system is operating at both its highest and lowest fan speeds, with little noticeable restriction of airflow through the forced-air system. The list price for this filter is $100, although we’ve seen it selling for less. Lennox recommends that you replace it once a year.
