- 97°FSpokane's August 2026 peak
- 88°FA typical summer high
- 26°FA typical winter low
- -10°FWhat severe winters can reach
Keeping wildfire smoke out of a Spokane house
Smoke season has become a regular part of summer in eastern Washington. Your heating and cooling system can either pull that smoke through the house or help clean it out. The difference is mostly in the filter and the fan setting.
- Answered 24/7
- Diagnosis before parts
- Written price first
NBy Nell Bradshaw, HVAC Guides Editor · Updated September 2026
Quick answerTo keep wildfire smoke out of a Spokane house, close windows, fit the furnace or air handler with a high-grade media filter in a sealed rack, run the system fan continuously so all the air passes through it, and switch any ventilator to recirculate. After a long smoke event, change the filter early and have the blower checked.
What August 2026 showed us
In August 2026 homes across Spokane and Spokane Valley sat in smoke from the Old Trails, Autumn Lane and Fairview fires. Omak, where our head office is, sees its own long smoke periods when fire smoke settles into the Okanogan valleys. Houses with basic one-inch filters pulled that smoke through the returns for weeks, and many owners noticed the smell every time the system started.
Why the filter matters most
Smoke particles are extremely small. A thin fiberglass filter catches lint and hair and lets smoke straight through. A pleated media filter in a four or five-inch cabinet has enough surface area to use a much finer grade without choking the blower, and it lasts months rather than weeks.
Fit matters as much as grade. A filter with a gap around it lets air bypass it completely. A sealed cabinet, part of our indoor air quality upgrades, closes that gap.
Run the fan, not just the heat or AC
The filter only works when air moves through it. On smoke days, set the thermostat fan to On so the blower runs continuously, even when the house does not need heating or cooling. Many smart thermostats can run the fan on a schedule for a set number of minutes each hour. The extra electricity is modest compared with the benefit.
Want a filter that actually stops smoke?
Call (509) 404-0016Ventilators and fresh-air intakes
Homes with an ERV, HRV or fresh-air intake bring outdoor air in on purpose. On smoke days that is the wrong direction. Switch the ventilator to recirculate or off, and close any fresh-air damper. Once the air clears, turn it back on so the house does not get stale. Our ventilation installs include a control that makes that switch easy.
Small steps that add up
A few habits help during a smoke event:
- Keep windows and doors closed and use the garage door as little as possible.
- Avoid adding indoor smoke from candles, frying or vacuuming without a HEPA filter.
- Set up one clean room with a portable HEPA purifier for sleeping if the whole house is struggling.
- Check the outdoor air quality index before opening up again.
After the smoke clears
A long smoke event loads the filter far faster than normal, so change it early even if the calendar says it has months left. If the smell returns every time the system runs, smoke residue may be on the blower wheel or in the return ducts. A blower cleaning, and sometimes duct cleaning focused on the return side, clears it.
Planning before next summer
The best time to upgrade filtration is before smoke season, not during it, when everyone calls at once. A spring visit can add a filter cabinet, check static pressure so the blower can handle it, and set the fan schedule. Pair it with an AC tune-up and the system is ready for both heat and smoke. For dry winter air, see whole-house humidifiers.
More Spokane heating and cooling guides
Smoke season questions
What filter grade should I use for smoke?
A high-grade pleated media filter in a deep cabinet. Very fine one-inch filters can restrict airflow, so check with a technician first.
Should I run my AC during smoke events?
Yes, with windows closed and a good filter. Run the fan continuously even when cooling is not needed.
Do portable purifiers help?
Yes, especially in bedrooms. Whole-house filtration covers the rest of the house.
Should I turn off my ERV during smoke?
Switch it to recirculate or off until the outdoor air clears.
How often should I change filters after smoke?
Early. A long smoke event can load a filter in weeks.
Get ready for the next smoke season.
Call about filtration upgrades in Spokane, WA.
