Getting the house ready before the smoke arrives

Why preparation beats reaction

Recent Washington summers have taught the pattern: air quality can go from clear to hazardous in a day, and once it does, portable air cleaners sell out, high-MERV filters disappear from shelves, and HVAC schedules fill with urgent calls. Everything that makes a smoke week tolerable — the right filter already installed, a system verified to handle it, spare filters in the closet, cooling that works with the windows shut — is cheap and easy to arrange in May and difficult in August. Treat smoke readiness like the Northwest treats earthquake kits: assembled calmly, in advance, hopefully never needed.

Filtration, verified in advance

The core upgrade is a filter that actually captures fine smoke particles (PM2.5) — typically MERV 11–13, or better, a 4–5 inch media cabinet that reaches high capture rates without choking your blower. The 'verified' part matters: not every system can pull air through a dense filter, and finding that out during a smoke event is the wrong time. A spring tune-up visit can measure your static pressure and confirm what your blower supports. Mini-split households should plan differently — those filters are designed for dust, so a portable HEPA unit for the bedroom is the usual answer.

Know your recirculate settings

Some homes actively pull outside air in: HRVs and ERVs, fresh-air dampers on the return duct, and continuously running ventilation fans. During a smoke event you want those set to recirculate or temporarily off, and the middle of a hazardous-air day is a bad time to be reading manuals. Find the controls now, learn which setting is which, and label them if that helps. Likewise, know which exhaust fans depressurize the house (big range hoods especially) — during the worst hours, they pull smoky air in through every gap in the envelope.

Spares, sealing habits, and a clean room

Stock at least one spare filter per system — smoke loads filters far faster than normal dust, and a filter that's captured a week of smoke needs changing, not admiring. Build the household close-up habit: windows latched (latched windows seal better than merely closed ones), doors closed promptly, pet doors blocked during the worst stretches. If someone in the home has asthma or a heart or lung condition, designate one bedroom as the clean room: a portable HEPA unit sized for the room, door kept closed, and cooling that reaches it. That single room strategy is what health agencies recommend and it works.

Common questions