Decisions Wildfire smoke Both sides
Windows open or closed when it's smoky and hot?
Keep them closed or Open when the air improves or Go somewhere cooler
Compared by the people who run this site. Updated . Rebates and prices checked November 3, 2026.
Windows open or closed in smoke and heat: keep them closed, unless it gets too hot to stay safe, and then the answer is to go somewhere cooler. Washington DOH's wording is "Close windows and doors, unless it is too hot to maintain safe temperatures." Open up when the air improves, even for a while.
The verdict, by situation
If there is smoke outside and the house is still at a safe temperature
Keep them closed. That is DOH's instruction, and it applies until the heat says otherwise.
If there is smoke and the house has become too hot, and you have no AC
Go somewhere cooler. DOH's exception is about temperature, and it points to a cooler place and 2-1-1, not to sitting it out at home.
If it is smoke-free and the air outside is cooler than inside
Open them. That is EPA's window rule. If the air outside is hotter than inside, close them.
If the air improves, even temporarily
Open up and run exhaust fans. EPA says to open windows or the intake, and run exhaust fans, while it lasts.
If you have central AC and smoke outside
Closed, with the fan On. EPA says to run the fan all the time, or the air is only cleaned while cooling.
If too much smoke still gets in, or the power goes out
Leave. That is one of EPA's triggers for shelter elsewhere.
Side by side
| Compare | Keep them closed | Open when air improves | Go somewhere cooler |
|---|---|---|---|
| When it fits | Smoke, safe temperature | A clean break in the smoke | Too hot, or too smoky indoors |
| Source line | DOH on windows and doors | EPA on air improving | EPA on seeking shelter; DOH on a cooler place |
| What to run | Air cleaner, AC, fan On if central | Exhaust fans | Nothing at home |
| What to check | Indoor temperature | AQI, smoke blog, outdoor temperature | 2-1-1 for cooling centers |
| Main catch | House overheats | The break can end quickly | You need a place and a way to get there |
Sources: Washington DOH: smoke, EPA: wildfires and indoor air, EPA: heat and smoke guide, EPA: clean room. Neither agency prints an indoor temperature for "too hot" on these pages, so we don't add one. For fan temperature lines, see fans or AC.
What would change the answer
- Someone gets dizzy, nauseated or develops a headache in the heat: don't wait on the air quality, move somewhere cooler. Heat stroke signs such as confusion, slurred speech or fainting mean call 911.
- The AQI reaches Orange and someone at home is sensitive, or Red for anyone: limit activity, and treat the clean room as the plan.
- You get a clean morning or evening: open up, and close again if smoke returns.
- Burn bans are in force nearby: wood stove use is limited, and EPA also lists gas, propane or wood stoves and furnaces, and vacuuming without HEPA, among things to avoid during smoke.
- You have no way to cool or filter any room: going elsewhere comes first, not last.
What it costs, with dates
This page is mostly about what you do rather than what you buy. Where money comes in, it goes to cooling and filtration, and we found no official installed price for any of it. If you get a contractor's bid for that work, have it written and itemized.
The steps that cost little are closing up, watching a thermometer and using the AQI map. As of November 2026 we found no rebate for a room cleaner or filter. The cooling side of this decision is on one cool room or the whole house, and the filter side on HEPA cleaner or MERV 13 filter.
Who does the work
You make this call, day to day, without a contractor. The tools are a thermometer in the room you use, the Ecology smoke map and the Washington smoke blog.
A contractor comes in only if you want the system set up better before next season: finding the outdoor damper, or confirming the filter slot. Check the company on L&I's tool first.
Why is smoke plus heat worse than either alone?
EPA treats the combination as its own hazard. Its guide says that together they "may be much worse for your health than exposure to either of them alone."
There is a practical trap as well. The same guide warns that the coolest time of day can be the smokiest, so the evening you would normally open up may be the worst time for it. Check the AQI before you open, not only the thermometer.
Keep the fan line separate. Fan limits are written differently by CDC and EPA. Fans or AC has each agency's wording.
What do the AQI colors mean for your house?
Washington DOH uses these bands:
- Yellow, 51-100: some people react.
- Orange, 101-150: sensitive people limit activity.
- Red: everyone limits activity.
DOH says smoke season typically starts in July or August and can begin as early as May. The Ecology map shows monitors near you.
Should you stay or go?
Stay if the house is at a safe temperature and you have a room with cleaner air. Go if any of EPA's conditions apply. EPA names three: you can't stay cool at home, the electricity goes out, or too much smoke is still getting in.
Prepare your clean room with windows and doors closed, but as EPA says, "don't do anything that makes it hard to get out". In Washington, 2-1-1 finds cooling centers. The west side and east side overviews show how this fits each climate.
What people ask next
Should I open the windows at night during a smoky heat wave in Washington?
Only if the air outside is cooler than inside and the smoke has eased. EPA warns the coolest time of day can be the smokiest, so check the AQI first.
Is it safe to stay in a closed-up house with no AC during smoke?
Only while it stays at a safe temperature. DOH's instruction to close up carries the exception "unless it is too hot to maintain safe temperatures". After that, go to a cooler place, and dial 2-1-1 for options.
Where do I find out how smoky it is right now in my town?
The Ecology monitor map and the Washington smoke blog are two places to check.
Decide next
Should you cool one room or the whole house?
- One cool room
- West side homes, no ducts, a modest budget, a room you can close
- Whole-house cooling
- East side summers, existing ducts, people home through the heat
HEPA air cleaner or MERV 13 filter for wildfire smoke?
- HEPA room cleaner
- Homes without ducts, and one clean room in any home
- MERV 13 furnace filter
- Homes with ducted forced air and a slot that fits
Are fans enough, or does your Washington house need AC?
- Fans
- Mild days when the indoor reading stays within the agency lines
- Air conditioning
- Any home planning for a heat wave, or for people at home all day
Where this came from
- Washington DOH: protect yourself from smoke, checked November 3, 2026.
- Washington DOH: extreme heat, checked November 3, 2026.
- EPA: wildfires and indoor air quality, checked November 3, 2026.
- EPA: heat and smoke guide (PDF), checked November 3, 2026.
- EPA: create a clean room, checked November 3, 2026.
- EPA: extreme heat and indoor air quality, checked November 3, 2026.
- CDC: heat and health, checked November 3, 2026.
- NWS: heat illness, checked November 3, 2026.
- Washington Ecology: wildfire smoke, checked November 3, 2026.
- Washington smoke blog, checked November 3, 2026.
- L&I: verify a contractor, checked November 3, 2026.