How to keep wildfire smoke out of your home

Anyone who has lived in the Sacramento Valley for a few summers knows the orange skies and the smell of smoke drifting in from fires hundreds of miles away. When the air quality index climbs, home should be the safe place. Here's how to make sure it is.

Why smoke gets inside

Wildfire smoke is made of extremely fine particles (PM2.5) that slip through gaps around doors and windows, bathroom and kitchen vents, and, very commonly, leaky return ducts in the attic. Once inside, those particles stay suspended in the air unless something filters them out.

1. Upgrade your HVAC filter

Standard fiberglass filters do almost nothing for smoke. A MERV 13 filter captures a large share of fine smoke particles. The catch: a thin 1-inch MERV 13 filter can restrict airflow in some systems. A 4- or 5-inch media filter cabinet lets you use high-efficiency filtration without straining your equipment.

During heavy smoke, check the filter every week. It can load up quickly.

2. Run your system fan

Your filter only cleans air that passes through it. Setting the thermostat fan to "On" instead of "Auto" keeps air moving through the filter continuously, even when the system isn't heating or cooling.

3. Seal up the house

• Keep windows and doors closed.
• Close the fireplace damper.
• If your system has a fresh-air intake, close it during smoke events.
• Use weatherstripping on drafty doors and windows.

4. Fix leaky return ducts

This is the one most people miss. Return ducts pull air back to your system. If they leak in a dusty, smoky attic, they pull that air straight into your living space and bypass your windows entirely. Sealing return ducts is one of the most effective long-term improvements for indoor air. Learn about our duct sealing services.

5. Add a portable HEPA purifier

For bedrooms, especially for kids, older adults, and anyone with asthma, a portable HEPA air purifier sized for the room adds an extra layer of protection overnight.

6. Avoid adding pollution indoors

Skip the candles, incense, frying, and vacuuming (unless it has a HEPA filter) on heavy smoke days. All of them add fine particles to air you're trying to keep clean.

After the smoke clears

Replace your filter once the smoke season winds down, and consider having your system checked. Ash and soot can coat the outdoor coil and reduce efficiency.

This article is general information, not medical advice. If you have health concerns related to smoke exposure, talk to your doctor and follow guidance from local air quality authorities.