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Wildfire Smoke and Your HVAC: Protecting Indoor Air Quality

When wildfire smoke fills Bay Area skies, your HVAC system becomes your first line of defense for healthy air.

Sarah MartinezAugust 24, 20248 min read

How Smoke Affects Indoor Air

Fine particulate matter (PM2.5) from wildfire smoke penetrates buildings easily. Without intervention, indoor air quality can match hazardous outdoor levels.

Upgrading Your Filtration

Replace standard filters with MERV 13 or higher—these capture most smoke particles. HEPA filters provide even better protection but require compatible systems.

Running Your Fan Continuously

Set your thermostat fan to "ON" instead of "AUTO" during smoke events. This continuously filters air even without heating or cooling.

Sealing Your Home

Check window seals, door weatherstripping, and close fireplace dampers. Cover gaps around AC window units with plastic and tape.

Portable Air Purifiers as Backup

For bedrooms and high-occupancy rooms, HEPA air purifiers provide additional protection. Run them on high during worst air quality days.

Filter Replacement After Smoke Events

Smoke-laden filters clog quickly. Check and replace filters more frequently during and after wildfire season—sometimes weekly during severe events.

Frequently Asked Questions

Quick answers to common questions

Most central AC recirculates indoor air, so a good filter helps. Fresh air intake vents should be closed or sealed during smoke events.

With good filtration and sealed openings, air quality improves within hours. Opening windows once outdoor air clears speeds recovery.

Related topics:

wildfire smoke HVACair qualitysmoke filtration

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