Choosing an HVAC Air Filter During Wildfire Smoke

MERV 13 may be useful when supported

MERV 13 is often considered for finer particles, including smoke. Confirm that your system and filter cabinet can use it without creating excessive airflow restriction.

Run the system appropriately

Use recirculation settings when available and avoid drawing outdoor air into the home when outdoor smoke is severe, unless your equipment instructions say otherwise.

Inspect filters frequently

Smoke can load a filter faster than normal conditions. Check the filter during and after a smoke event and replace it when visibly dirty or airflow declines.

Do not rely on one measure

Close gaps, limit indoor particle sources, and consider a properly sized portable air cleaner for occupied rooms. Follow local public-health guidance during smoke events.