What Should You Do About Wildfire Smoke Inside Your Home?

Stop firstFollow evacuation and emergency instructions. If anyone has new, worsening, severe, or concerning symptoms—or the home cannot remain safely cool—use appropriate medical, emergency, or local guidance.

WILDFIRE SMOKE AT HOME

What do you need right now?

Go directly to a task, or use the guided path if you are not sure.

Take immediate smoke stepsSee what to do now, what not to do, and when local or medical guidance takes priority.

Useful nowReduce smoke entry Avoid adding particles indoors Choose one room that can stay cool

STOP FIRST

Stop Here First: Health, Heat, or Unsafe Conditions

Ordinary home-air steps are no longer the main task if any of these apply.

Significant breathing difficulty, chest pain, severe symptoms, or worsening symptoms.
Asthma, COPD, cardiovascular disease, pregnancy, young children, older adults, or another medical vulnerability changes the risk.
The home or cleaner room becomes dangerously hot.
Smoke keeps getting in and no tolerable lower-smoke room is possible.
Local officials issue evacuation, shelter, smoke, heat, or public-health instructions.

Keep More Smoke Outside

First, reduce entry. This is useful whether or not you later use filtration.

Keep windows and exterior doors closed as much as practical.
Reduce repeated door openings.
Close or avoid outdoor-air intakes where your system supports that.
Avoid equipment settings that pull smoky outdoor air inside.
Keep exits usable.

This is not a rule to keep windows closed no matter what. If outdoor air improves, airing out may be appropriate. If the home becomes too hot, stale, symptomatic, or unsafe, local guidance and cleaner-air or cooler locations override generic closed-window advice.

Avoid Making Indoor Air Worse

During smoke, avoid adding indoor particles.

Smoking or vaping.
Candles, incense, fireplaces, or unnecessary combustion.
Frying or broiling.
Aerosol sprays and air fresheners.
Vacuuming unless the vacuum has HEPA filtration.
Strenuous activity inside the cleaner room.

For a short or lower-risk event, smoke-entry control plus indoor-source reduction may be enough.

Create One Cleaner Room

The center of the plan is one room where smoke and particles are lower than elsewhere. It is cleaner, not guaranteed safe.

Choose

Large enough for the people who need it.
Comfortable for long stretches.
Easy to close off.
Low in windows, exterior doors, fireplaces, and obvious smoke-entry paths.
Able to stay cool.
Compatible with existing airflow or filtration if used.

Avoid

Gets too hot.
Smells strongly smoky after closure.
Needs frequent outside-door traffic.
Contains a fireplace or obvious smoke path.
Would be hard to leave quickly.

Set Up

Close windows and the room door.
Reduce traffic in and out.
Keep cooking, candles, smoking, vaping, aerosols, and heavy cleaning out of the room.
Use shades, fans, or air conditioning where safe.
Keep needed medications, water, chargers, and care supplies nearby.
Add existing filtration if available.

A cleaner room that gets dangerously hot is not a successful plan. Existing HVAC, a portable cleaner, or a DIY filter can support the room. They do not define it.

Use What You Already Have

Use existing conditions and equipment correctly before adding anything.

Central HVAC

Helpful when it can recirculate indoor air through a compatible filter without pulling in outdoor smoke.

Filters

Use the highest-efficiency filter your system can handle. Do not assume MERV 13 or higher is compatible with every system.

Window AC

Useful only if the outdoor-air damper can be closed and the window seal is tight.

Portable AC

Single-hose units can draw smoky air in from elsewhere and should be used sparingly in smoky conditions unless cooling need changes the safety balance. Two-hose units still need a tight seal.

Fresh-air systems / ERVs / HRVs

Treat these as system-specific. Use documentation, building management, manufacturer support, or HVAC guidance rather than guessing.

Add Filtration Only If Needed

Filtration is a role, not a shopping category. Match it to the room and the risk.

No Added Equipment

Best fit: Indoor air seems okay, the event is short, and the room stays tolerable.
Helps with: Entry control and source reduction.
Know first: Outdoor conditions, indoor signs, and heat.

Existing HVAC Filtration

Best fit: Central HVAC can recirculate through a compatible filter.
Helps with: Recirculated particle reduction.
Know first: Settings, outdoor-air intake, and filter compatibility.

Portable Air Cleaner

Best fit: One room needs active filtration.
Helps with: Room-level particle reduction.
Know first: Smoke CADR or room-size rating, room size, and ozone-safe status.

DIY Filter

Best fit: Temporary fallback when known-performance cleaners are unavailable or unaffordable.
Helps with: Particle reduction if safely built and used.
Know first: 2012+ UL/ETL fan, high-efficiency filter where available, supervision, and no extension cord.

Multiple-Room Strategy

Best fit: Longer event or more than one occupied room needs help.
Helps with: More room-level coverage.
Know first: Which rooms matter, capacity, and filter maintenance.

Professional / Whole-Home Path

Best fit: Repeated events, high-risk household, HVAC uncertainty, or fresh-air systems.
Helps with: Building and system planning.
Know first: HVAC assessment, documentation, and local guidance.

Choosing a portable air cleaner?Use room size, smoke CADR, ozone safety, noise, and filter cost to narrow the options →

DIY Filter Boundary

A DIY fan/filter setup may be a temporary fallback, not a construction project inside this hub.

Use a newer 2012+ box fan with UL or ETL marking.
Follow manufacturer instructions.
Do not use an extension cord or damaged fan.
Do not leave children unattended with the fan.
Keep working smoke detectors present.
Use a high-efficiency filter where available and keep airflow unobstructed.

The Few Terms That Matter

AQI

Outdoor smoke-risk and timing signal; not an indoor measurement.

PM2.5

Fine smoke particles tied to much of the short-term health concern.

HEPA

Particle filtration. It does not mean all smoke gases or odors are removed.

MERV

HVAC filter-efficiency rating. Higher can help, but compatibility matters.

CADR

Clean-air delivery rate for matching a portable cleaner to a room.

Odor and CO2 are not smoke-particle measurements. Odor is an imperfect warning sign; CO2 can indicate ventilation or stale air only if the device measures CO2.

When the Answer Changes

Outdoor air improves

Airing out the home or cleaner room may be appropriate.

The cleaner room gets hot

Cooling or a cleaner-air and cooler location can become the priority.

Smoke lasts longer than expected

Reassess filters, symptoms, local guidance, and whether staying remains tolerable.

Smoke stays obvious indoors

Treat this as a cleaner-air relocation or professional/system question, not just an equipment problem.

Household risk is higher

Keep clinician/public-health guidance and action plans in the frame.

HVAC details are unclear

Use documentation or professional help; do not guess at fresh-air or filter settings.

What Should You Do Next?

Stay with no-purchase measuresIf smoke is mainly outside, the household risk is lower, and one room remains tolerable.

Build or maintain one cleaner roomIf smoke is entering, the event is uncertain, or someone needs a lower-smoke place to spend time.

Use existing filtrationIf HVAC or an existing portable cleaner can support that room without pulling in outdoor smoke or violating equipment limits.

Investigate room-level filtrationIf the cleaner room still needs active particle reduction and filtration can be matched to the room.

Get HVAC guidanceIf outdoor-air intake, MERV compatibility, ERV/HRV behavior, portable AC effects, or whole-home changes are unclear.

Seek clinician or public-health guidanceIf symptoms or household vulnerability changes the risk.

Use a cleaner-air locationIf the home cannot remain cool, tolerable, and lower-smoke, or if local officials tell you to leave or use a shelter.

SELECTED SOURCES

Research behind this guide

EPACreate a Clean Room to Protect Indoor Air Quality During a Wildfire ?EPAWildfires and Indoor Air Quality (IAQ) ?EPADIY Air Cleaners ?CDCHow Wildfire Smoke Affects Your Body ?AirNowWhen Smoke is in the Air ?AirNowIndoor Air Filtration factsheet ?CARBIndoor Air Cleaners and Wildfire Smoke FAQ ?AHAMHow to Use an Air Cleaner Effectively in Areas with Wildfire Smoke ?

Fully Considered uses authoritative wildfire-smoke and indoor-air guidance to govern claims, safety interruptions, filtration boundaries, and the distinction between outdoor signals and indoor conditions.