Short answer
During dust or smoke events, close windows, run the HVAC fan with the best filter your system can handle (ideally MERV 13 in a media cabinet), turn off fresh-air intakes, and replace the filter afterward. A portable HEPA purifier helps in bedrooms.
During the event
Keep the house sealed and let the filter work.
- Fan set to On, not Auto
- Close outside air dampers and ERV intakes
- Avoid running swamp coolers, which pull in outdoor air
After
Check and replace filters, rinse the outdoor coil once winds calm down, and look at the evaporative cooler pads if you have them.
Upgrades worth considering
Media filter cabinets, sealed returns, and ERVs with good filters all help year after year.
Questions
Should I run my swamp cooler during smoke?+
No. Evaporative coolers pull outdoor air in. Switch to AC or recirculation if you have it.
Editorial note: this guide is general information for homeowners, not a diagnosis. Desertline Heating & Air is a referral service; a licensed contractor should inspect your equipment before repairs.