Updated August 3, 2026
Right now in the Puget Sound: Smoke from Eastern Washington fires is settling over Western Washington through midweek, according to the NWS Seattle forecast discussion and a wildfire smoke alert from the Puget Sound Clean Air Agency issued August 3.
Closing your windows helps, but it doesn’t seal your home from outdoor air. Smoke particles work their way in through exhaust fans, fireplace flues, leaky ductwork, and the small gaps around doors and windows, and they can linger indoors well after the outdoor haze clears. Here’s what actually helps, in the order that matters most.
Do this now
- Check current air quality at AirNow as conditions shift by neighborhood and hour.
- Close windows and exterior doors and latch them fully; locking a window usually compresses the weatherstripping tighter than just closing it.
- Set your HVAC to recirculate indoor air instead of pulling in outside air, if your system has that option.
- Check that your filter fits and is clean. A filter with gaps around the edges lets air bypass it
- Upgrade to a MERV 13 filter, or the highest rating your system can handle without choking airflow (more on this below).
- Run a properly sized portable HEPA air cleaner in whichever room your household spends the most time.
- Skip anything that adds particles indoors such as candles, frying, aerosol sprays, dry sweeping, a wood-burning fireplace.
Don’t force a change you’re not sure about. Closing an unfamiliar damper or disabling ventilation your combustion appliances rely on can create a bigger problem than the smoke. When in doubt, ask an HVAC pro.
Is your HVAC helping or hurting?
Most systems can filter smoke when they’re recirculating through a properly fitted filter, but “most” isn’t “all.”
Central AC, furnaces, and ducted heat pumps can double as air filters when set to recirculate.
Ductless mini splits are great for cooling a room without opening a window, but their washable screen catches lint and dust, not fine smoke particles. Pair one with a portable HEPA unit if you need real filtration.
No central HVAC? Lean entirely on a correctly sized portable HEPA cleaner in your main living space, with windows and doors shut.
Homes with fresh-air systems such as ERVs, HRVs, whole-house fans, are often designed to bring outside air in on purpose. Don’t switch them off blind. Check the manual or call your HVAC company first.
MERV vs. HEPA
MERV 13 is the EPA’s and Washington State Department of Health’s recommended minimum for wildfire smoke, but only if your system can accept it without choking airflow. A filter that is too restrictive in an incompatible system can hurt more than it helps. True HEPA filtration captures more, but most residential ducted systems aren’t built to run one as a drop-in filter; that’s what portable HEPA units are for.
Does duct cleaning fix wildfire smoke?
Not by itself, and we won’t tell you it does. Your first moves are sealing up the house, filtering the air you already have, and cutting indoor particle sources, not duct cleaning. It’s worth a look when you’re also seeing visible debris in the ducts, air appears to be bypassing the filter, or odor lingers well after outdoor air, and household surfaces have been addressed. Duct inspection and cleaning is one tool among several, not a universal fix, and treating it as one is how homeowners end up paying for a service that doesn’t solve the actual problem.
After the smoke clears
Don’t judge it by the sky, check AirNow before you open up. Once readings improve, ventilate the house, restore any fresh-air systems to their normal settings, inspect and likely replace your HVAC filter and any portable HEPA filters, and clean settled dust with a damp cloth, wet mop, or HEPA vacuum rather than dry sweeping, which just puts particles back in the air.
Frequently Asked Questions
Can wildfire smoke get inside a closed house? Yes. Closing windows and doors helps, but most homes aren’t airtight, smoke enters through exhaust fans, fireplaces, outdoor-air intakes, and ordinary gaps around doors and windows.
Should I run my HVAC during wildfire smoke? Usually yes, if it’s set to recirculate through a clean, correctly fitted filter. Reduce outdoor-air intake only if your system allows it, and watch for weak airflow or unusual noise.
What MERV filter is best for wildfire smoke? MERV 13, or the highest your system can handle without restricting airflow. Not every system can safely run one; check with an HVAC technician if you’re unsure.
Does a HEPA filter remove wildfire smoke? It captures the fine particles that pass through it, but it doesn’t remove every gas or odor, and results depend on the unit’s size, placement, and runtime.
When should I open my windows again? Once AirNow or PSCAA readings show conditions have actually improved, not based on how the sky looks.
Can duct cleaning remove smoke odor? Sometimes it can, if inspection shows debris, filter bypass, or damaged ducts are the cause. It’s not a stand-alone fix for an active smoke event.
Why does my house still smell smoky after the air outside clears? Particles and odor can linger in filters, carpets, furniture, and curtains, or point to air leakage or filter bypass that’s worth a look.
When to call a pro
Smoke odor that won’t quit, weak or uneven airflow, a filter that gets dirty unusually fast, or one room that’s consistently worse than the rest of the house are all worth a proper look. Filter fit, duct condition, and air leakage interact with each other, and a new filter alone won’t fix all three.
Home Comfort Alliance serves Seattle, Tacoma, Bellevue, Redmond, Everett, Bremerton, and the surrounding Puget Sound. Find your area or schedule an indoor air quality check, or call (425) 645-0404.
