Wildfire Smoke Home Plan: Keep Indoor Air Safer

Wildfire smoke is not just "smoky air." It contains a complex mix of gases and fine particles (PM2.5) that can bypass your body's natural defenses. When the sky turns orange, you need a plan that goes beyond just closing the window.

1. The "Clean Room" Concept

You probably cannot filter your whole house perfectly during a massive smoke event. Focus your efforts on one "fortress" room.

• Choose the Room: Usually the master bedroom or a large living area where the family sleeps/gathers.
• Seal It: Close the door. Use painter's tape to seal gaps around the window frame if it's drafty.
• Run the Purifier: Place your largest HEPA unit here and run it on "High" 24/7. Do not use "Auto" mode; the sensors might not react fast enough to leakage.

2. HVAC Triage

Your central heating/cooling system can be a hero or a villain.

• The "Fan On" Trick: Turn your thermostat fan setting from "Auto" to "On." This circulates air through your filter continuously.
• Upgrade the Filter: Swap your standard filter for a MERV 13 (or FPR 10/MPR 1900). This is the minimum rating that effectively catches smoke particles.
• Close the Fresh Air Intake: If your system has a mechanical fresh air damper (common in newer homes), close it. You do not want outdoor air right now.

3. Stop Adding Pollution

Indoor air is already compromised. Don't make it worse.

• No Frying: Cooking steak or bacon releases massive amounts of PM2.5. Eat sandwiches or microwave meals.
• No Candles/Incense: This should be obvious, but people forget.
• No Vacuuming: Unless you have a sealed HEPA vacuum, you are just kicking settled dust back into the air.

4. DIY Filtration (The Box Fan Hack)

If you don't have an expensive purifier, you can build a "Corsi-Rosenthal Box" for under $100.

• Materials: One 20-inch box fan, four 20x20 MERV 13 filters, duct tape, and the cardboard box the fan came in.
• Assembly: Tape the filters into a cube shape, place the fan on top blowing up, and seal the bottom with cardboard.
• Performance: Tests show these can outperform $500 commercial units in pure particle removal speed.

5. Post-Event Cleanup

When the smoke clears, the particles settle on surfaces.

• Change Filters: Smoke clogs HVAC and HEPA filters rapidly. Replace them immediately after the event ends.
• Damp Mop: Wipe floors and surfaces with a damp cloth to trap the settled ash. Don't dry dust.

Summary

Preparation prevents panic. Buy your MERV 13 filters before fire season starts, because they will be sold out when the smoke arrives.