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Sep 11, 2023

Best Air Filters or Dealing With Wildfire Smoke in Your Home

Follow CR's advice for improving indoor air quality with filters for your HVAC

Follow CR's advice for improving indoor air quality with filters for your HVAC system

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You don't have to live in a wildfire zone to experience the bad effects of wildfire smoke, which can drift for hundreds, if not thousands, of miles, bringing unhealthy air conditions as it travels.

With such dirty air outside, it can be difficult to keep the air inside your home clean. Even if you keep your doors and windows closed, which is recommended, air can seep in through cracks and leaks. One way to clear the air is by running the fan on your central heating or cooling system so that it cycles through the filter. If your system has a fresh air intake, set it to recirculation mode or close the outdoor intake damper so that you do not draw polluted air inside, the Environmental Protection Agency advises.

An HVAC air filter will catch much of the smoke that's in your home—assuming it's a good one.

"You want a filter with a high MERV rating," says Dave Trezza, an engineer who has tested air filters at Consumer Reports. MERV stands for minimum efficiency reporting value, and the higher it is, the more contaminants the filter removes. The top performers in our tests typically have a MERV rating higher than 10, and range in thickness from 1 inch to 5 inches.

For getting rid of smoke and other household pollutants, "any filter that gets a very good or excellent score in our tests when the system is running on high would be a good choice," Trezza says.

Robert Hamerly, the principal of GreenSavers, an energy efficiency and HVAC company based in the fire-prone Oregon cities of Bend and Portland, says you’ll want to change your filters more often during fire season because they get dirtier faster. (Even if you’re not dealing with a ton of smoke, if you’re spending more time indoors, you should check your filter more often.)

Check the filter to see whether it looks dirty. You may also notice a degradation in airflow. Both are indications that the filter is not cleaning the air properly, and you’ll need to replace it. You can buy air filters in packs online and at home improvement stores. Some online retailers also offer subscriptions so that your supply is automatically replenished every month or in the time frame you choose.

Here are four air filters from our tests that earn top scores for smoke removal when used on high speed. For more choices, check out the best air filters for your central air system and furnace.

Below, you’ll also find more tips for keeping smoke out of your house, as well as measures to take against smoke from the next wildfire.

In addition to using a high MERV filter in your HVAC system, follow these additional steps to keep healthy air in your home and smoke out. What to Do Now if There's Smoke in Your Area • Keep all doors and windows closed. • If air is seeping in around windows and under doors and you don't have caulking or the other supplies you need to seal them, use duct or package tape to tape around your window frame where you feel a draft, and put towels in front of the doors. • Even if you don't need your central air conditioning for cooling, you can run just the fan on your HVAC system on a low setting to filter the air in your home. If your system has a fresh air intake, close it or set the system to recirculate to avoid drawing in bad outdoor air.

What to Do Before the Next WildfireWildfire season seems to be getting longer, but when one subsides, there are a number of things you can do to prepare for the next one, Hamerly says.

• Seal all leaks. Walk around the house to see where you feel drafts, usually around windows and doors. • Use caulk to seal your windows and doors from both the inside and outside. (You’ll need different types of caulk for the interior and exterior; ask at your hardware or home improvement store.) Always remove the old caulk before replacing it with new. Covering loose caulk is an exercise in futility because it won't seal the leak. • Consider upgrading your air filtration system. In our tests, we found that thicker air filters were more effective at removing impurities. If your system accommodates the basic 1-inch-thick filter, you’ll need to have a pro install a larger filter box to accommodate a thicker size.

Mary H.J. Farrell

Mary H.J. Farrell is a senior editor at Consumer Reports whose real passion is for cooking and all that entails. She has expanded CR's cookware category to include not only more pots and pans but also other essentials like stand mixer attachments, sheet pans, and vacuum sealers. Mary also covers vacuums but finds cooking way more fun than cleaning. Since the mid-1990s, Mary has held senior positions at People.com, MSNBC, and Ladies’ Home Journal. One of her earliest jobs was at Good Housekeeping.