During smoke events, the goal is simple: keep outside air out and continuously filter the air inside. That means running the HVAC fan with the best filtration your system supports, closing up the house, and — for the smallest smoke particles — adding purification designed for PM2.5. Paper masks over vents and open-window 'airing out' do not help.
- Smoke's harmful fraction is fine particulate (PM2.5) — small enough to slip past basic filters and deep into lungs.
- Run the system fan continuously during smoke events so air keeps passing through filtration.
- Higher-grade filtration (dense media or HEPA-class purification) captures what standard filters miss.
- Prepare in June: smoke season in the Valley is a recurring event, not a surprise.
What smoke does to indoor air
Wildfire smoke is dominated by fine particulate — PM2.5 — which stays suspended for hours and penetrates buildings through every gap, duct leak, and door swing. Indoor levels during regional smoke events routinely reach a large fraction of outdoor levels in unprepared homes. The people who feel it first are kids, older adults, and anyone with asthma or heart conditions, but nobody benefits from breathing it.
The playbook during a smoke event
Close windows and doors and minimize traffic in and out. Set your thermostat fan from AUTO to ON so air circulates through the filter continuously rather than only when heating or cooling runs. If your system has a fresh-air intake, close or minimize it for the duration. Run any portable or whole-home purifiers on high in the rooms you occupy. And skip anything that adds particles indoors — candles, frying, vacuuming without a HEPA vacuum.
Equipment that earns its keep here
Three upgrades matter in a smoke-prone valley. A media filter cabinet — a thick, dense filter the blower can actually handle — outperforms 1-inch filters without strangling airflow. Whole-home purification (HEPA-class or polarized-media systems installed at the air handler) targets the fine fraction that filters pass. And duct sealing closes the leaks that pull smoky attic and crawlspace air into the system. We match the option to your system's blower capacity — over-filtering a weak blower trades smoke for airflow problems.
Key terms
The vocabulary you'll hear on estimates and service calls — defined in plain language in our glossary.
Where it goes wrong
The AUTO-fan mistake
On AUTO, the fan only runs while heating or cooling. In mild smoke-season weather, that can mean under an hour of filtration a day while particulate hangs in the air the other 23. Switching to ON during events is free and immediately effective.
Buying filtration your blower can't breathe through
A maximally restrictive filter jammed into a system designed for a standard one drops airflow, ices coils, and overheats the blower. Filtration upgrades are a systems decision — capture rate and pressure drop together, not capture rate alone.
How we build this guidance
- Written from real service and install work across the Wenatchee Valley — the orchard-dust, hydro-rate, dual-peak-climate conditions in this guide are the ones our techs work in daily.
- Rebate figures reflect published utility program terms at the date below and are re-verified on every estimate — programs change annually.
- No invented pricing: dollar figures appear only where a program publishes them.
Last updated: 2026-07-03 · Central Washington Heating and Air, licensed & insured (LIC# CENTRWH742JN)
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