Choosing an Air Purifier for Wildfire Smoke
Updated 2026-09-25
Wildfire smoke is mostly very fine particles — the kind that portable air purifiers with true HEPA filters are good at removing. Public health agencies, including the EPA, recommend portable air cleaners as one way to reduce indoor smoke exposure. The key is choosing one that's powerful enough for the room.
This is general information about air purifiers, not medical advice. If you have heart or lung conditions, follow your healthcare provider's guidance and local air quality alerts.
Look at smoke CADR
Purifiers often list three clean air delivery rates (CADRs). For wildfire smoke, smoke CADR is the one that matters — it measures the smallest particles. For a room with 8-foot ceilings, aim for a smoke CADR of at least two-thirds of the room's square footage, and more for smoke if you can: on AirSheet we size smoke rooms at 6 air changes per hour.
| Room | Smoke CADR to aim for (6 changes/hr) |
|---|---|
| 150 sq ft bedroom | 120 cfm |
| 250 sq ft bedroom | 200 cfm |
| 400 sq ft living room | 320 cfm |
Create a clean-air room
During a smoke event it's usually more effective to protect one room well than a whole house poorly:
- Pick a room you spend a lot of time in — often a bedroom.
- Keep windows and doors closed.
- Run the purifier on its highest setting you can tolerate.
- Avoid adding indoor smoke: no candles, frying or wood stoves.
Filters wear out faster
Heavy smoke loads a filter quickly. Expect to replace filters sooner than the usual schedule after a bad smoke season, and consider keeping a spare. Some brands offer smoke-specific filters with extra carbon for odor.
Find one that fits
The room matcher has a wildfire smoke setting that sizes for 6 air changes per hour. Or see our best purifiers for wildfire smoke, ranked by smoke CADR per dollar.