Best Filters For Dealing With Wildfire Smoke in Your Home

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

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Red sky with wildfire smoke Photo: Getty Images

In addition to the devastating loss of homes and businesses, wildfire season can bring unhealthy air conditions across the West.

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, to cycle air through the filter.

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, the engineer who runs Consumer Reports’ air filter labs. 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 they range in thickness from 1 inch to 5 inches.

More on Air Filters

For getting rid of smoke and other household pollutants, “any filter that gets a Very Good or Excellent 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. “We’re seeing a lot of dirty filters," he says. "They’re getting gummed up more than usual." (Even if you’re not dealing with a ton of smoke, if you’re spending more time indoors because of the pandemic, 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 the top four air filters from our tests—all earn an Excellent rating for smoke removal. For more choices, check out the best air filters for your furnace and central air.

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.

Best Air Filters for Smoke Removal

More Ways to Keep Smoke Out of Your Home

In addition to using a high MERV filter in your HVAC system, follow these additional steps to keep healthy air in 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 air conditioning, run just the fan on your HVAC system on a low setting so that you can filter the air in your home.

What to Do Before the Next Wildfire
Wildfire season seems to be getting longer, but when this 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 the thicker size.

Mary H.J. Farrell

Knowing that I wanted to be a journalist from a young age, I decided to spiff up my byline by adding the middle initials "H.J." A veteran of online and print journalism, I've worked at People, MSNBC, Ladies’ Home Journal, Good Housekeeping, and an online Consumer Reports wannabe. But the real thing is so much better. Follow me on Twitter.