Smoke smell in the house after a wildfire: indoor air first, attic second

When the sky turns orange and the house starts to smell of smoke, the attic is not the first thing to worry about. The air in the rooms where you sleep and breathe is. This page starts there, with what EPA and the California Air Resources Board (CARB) actually say, and only then turns to the attic: how smoke gets into it, why it can hang on there, and what to do before the next fire season.

We are an insulation company, not a health authority or a smoke-damage assessor. Everything about health and indoor air below comes from the agencies named, in their words as closely as we can put them.

While the smoke is here: the official steps

Know when it's coming. The Bay Area Air District issues an Air Quality Advisory when wildfire smoke is affecting the region, and can call a Spare the Air Alert for fine-particle pollution, which includes wildfire smoke. Smoke doesn't need a local fire: in August 2026 the District issued an advisory for smoke from wildfires in the Pacific Northwest. The Fire and Smoke Map at fire.airnow.gov shows conditions near you.

Run the central system to filter, not to ventilate. EPA says that if your system has a fresh-air intake, set it to recirculate or close the outdoor intake damper, and set the fan to "On" instead of "Auto" so it filters as often as possible. CARB says the same and adds: install a filter rated MERV 13 or higher, as high as your system can handle. EPA adds that the filter should fit snugly, with no air leaking around it, and that you should keep spares on hand during heavy smoke.

Don't pull smoke in. CARB: "Do not run swamp coolers or whole house fans." A whole-house fan exhausts through the attic and draws outdoor air in through the windows, which is the opposite of what you want.

Set up a clean-air room. CARB calls it a Clean Air Space: pick a room that fits everyone, close its windows and doors without blocking exits, and run a CARB-certified portable air cleaner continuously on its highest setting. EPA adds that the air cleaner should not produce ozone.

Cut indoor sources. CARB lists vacuuming among the activities that raise indoor pollution, and suggests a damp cloth or mop for settled dust.

How smoke reaches the attic, and from there the rooms

A vented attic is built to exchange air with the outdoors. Intake vents at the eaves and exhaust vents up high keep it dry the rest of the year, and in a smoke event they do exactly the same job with smoky air. For as long as the smoke lasts, the attic is full of it.

That would matter less if the ceiling below were airtight. Most aren't. EPA notes that outdoor air gets into a home through small openings, joints and cracks. In the ceiling those are the gaps around light fixtures, the attic hatch, plumbing and wire holes, and the boots where ducts meet the drywall. Air moving between the house and the attic through those gaps can carry smoke into the rooms.

Ducts are the other route. Where the heating ducts run through the attic, leaky joints on the return side can draw attic air into the system and blow it through the house.

None of this is a reason to block vents during a smoke event. Attic vents have a job, and sealing them shut is a design change, not an emergency fix. The useful work happens before the next event: sealing the ceiling, which is what air sealing is.

After the fire: when the house still smells of smoke

A smoky smell that lingers after the air outside has cleared is common, and the attic is one place it can linger. Loose insulation has an enormous amount of surface area, and fine particles settle into it.

Whether that's a passing odor or residue that needs removal is a question for an assessment, not a sniff test. California's Department of Insurance has spent the past two years on exactly this. Its 2025 bulletin told insurers not to deny smoke claims without an appropriate investigation. In September 2026 the Department announced that AB 1795, the Smoke Damage Recovery Act, had been signed, and summarized it as requiring insurers to pay for necessary testing and sampling.

This is not insurance advice. Your policy, your insurer and the specifics of your home decide what happens with a claim. The Department's consumer line is 1-800-927-4357.

What we'd say from the attic side:

• Don't stir it up first. EPA's advice on ash is to avoid anything that kicks particles into the air, such as dry sweeping. Pulling insulation around to "check" does the same.
• Take photos of the attic from the hatch, with the date, before anything is moved.
• If the smell is musty or animal rather than smoky, it's probably a different problem; see a smell coming from the attic.
• Once an assessment says the insulation should come out, insulation removal is work we do. Testing the residue comes first, and that's the assessor's job.

The fires that taught the Bay Area this

The North Bay knows smoke well. CAL FIRE's incident page for the Tubbs Fire, which started on October 8, 2017 in Napa and Sonoma counties, lists 5,636 structures destroyed. The Glass Fire, which started on September 27, 2020 in the same two counties, burned 67,484 acres and destroyed 1,528 structures. Santa Rosa and Napa sit in the counties where both fires burned, and San Rafael is next door. The August 2026 advisory is a reminder that smoke from fires hundreds of miles away reaches every part of the Bay too.

Before the next fire season

Smoke is one problem; embers are another. Embers can blow into an attic through its vents and start a fire inside the house. Ember-resistant vents use fine mesh or baffles to keep them out while still letting the attic breathe. Our ember-resistant vents page covers the code and the options vent by vent.

Hardening the house can also matter for insurance. The wildfire mitigation insurance discount guide covers how home hardening ties into insurance discounts in California, and where attic vents fit in.

The sensible order for a house in the hills: seal the ceiling, replace the vents, and keep the filters stocked.

Getting the attic side looked at

Book a free inspection or send photos and a short video from the hatch for an estimate. We'll look at the ceiling gaps, the vents and the ducts, and tell you plainly if what we see needs a smoke assessment before any insulation work. Nothing is due before you sign a written quote.