The windows are closed, but your home still smells smoky. Your eyes may feel irritated, the air may seem unusually heavy, or an indoor monitor may show rising particle levels.
You might not expect it, but wildfire smoke can travel far beyond the immediate area of the fire and enter homes through doors, windows, ventilation systems, and small openings in the building envelope.
To keep wildfire smoke out of your home, close windows and doors, limit outdoor air intake, seal obvious leaks, create a designated clean-air room, and continuously run a properly sized HEPA air purifier.
Keep reading this guide for Sylvane’s expert advice on keeping your home a smoke-free sanctuary.
How to Keep Wildfire Smoke Out of Your House | Checking Air Quality | Creating a Clean-Air Room | Using an Air Purifier | Filters Guide | What to Do When Smoke Clears | Wildfire Preparedness Kit
Why Wildfire Smoke and Smog Are Hard to Keep Outside
A home doesn’t need to look visibly smoky for outdoor pollution to have an effect on indoor air quality. Fine particles can enter through openings too small to notice, and everyday household equipment can influence how much outdoor air is pulled inside.
Smoke Enters Through More Than Open Windows
Closing windows is an important first step, but it doesn’t make your home completely airtight. Smoke may still enter through:
- Gaps around doors and windows
- HVAC fresh-air intakes
- Bathroom and kitchen ventilation systems
- Attached garages
- Chimneys and open fireplace dampers
- Spaces around utility lines
- Window-mounted equipment
- Frequently opened exterior doors
Exhaust fans, dryers, and pressure differences between the home and outdoors can also encourage replacement air to enter through cracks or planned intake vents. The amount of infiltration will vary according to the home’s construction, ventilation equipment, weather conditions, and proximity to the smoke.
The Main Concern Is Fine Particle Pollution
Wildfire smoke is a mixture of particles and gases. One of the most significant components to know about wildfire smoke is PM2.5, which refers to fine inhalable particles measuring 2.5 micrometers or smaller. These particles are dangerous because they can travel deeply into the respiratory system.
It helps to distinguish among different types of pollution:
- Particles: Ash, soot, dust, and other fine material suspended in the air
- Gases and Odors: Volatile organic compounds and combustion-related odors
- Smog: A broader mixture that can include particle pollution, gases, and ground-level ozone.
How to Keep Wildfire Smoke Out of Your House
Use these steps whenever outdoor smoke or smog raises the local AQI.
1. Close Windows and Exterior Doors
Keep doors and windows closed while outdoor air quality is poor. Limit unnecessary trips, use one primary entrance when practical, and avoid leaving doors open while unloading groceries or packages.
Ask household members to check the AQI before opening a window, even when the outdoor air looks clearer.
2. Set Your HVAC System to Recirculate
If your HVAC system or room air conditioner has an outdoor-air setting, switch it to recirculation during a smoke event when permitted by the manufacturer’s instructions.
Check the HVAC filter and replace it if it is dirty. The EPA recommends using at least a MERV 13 filter, or the highest-efficiency filter the system’s fan and filter slot can accommodate. But we recommend consulting an HVAC professional before installing a filter that may restrict airflow or exceed the equipment’s specifications.
3. Seal Obvious Air Leaks
Temporary sealing can reduce infiltration during an active wildfire outbreak, but permanent repairs are the best way to improve protection for future smoke seasons.
Consider these improvements:
- Install weatherstripping around exterior doors.
- Replace cracked or worn door sweeps.
- Lock windows tightly.
- Seal gaps around window air conditioners.
- Close fireplace dampers when the fireplace is not in use.
- Inspect openings around pipes, cables, and utility lines.
These measures can reduce smoke entry, but no typical home should be considered completely smoke-proof.
4. Limit Unnecessary Exhaust-Fan Use
Bathroom fans, range hoods, clothes dryers, and other exhaust equipment remove indoor air. That air must be replaced, often by outdoor air entering through leaks.
Reduce unnecessary exhaust use during heavy smoke, but continue using ventilation whenever it is needed for cooking safety, moisture control, or proper operation of combustion appliances. Never disable safety equipment or manufacturer-required ventilation.
5. Avoid Creating More Indoor Pollution
An air purifier is more effective when it does not have to compete with preventable indoor pollution. During a smoke event, avoid or reduce:
- Smoking or vaping indoors
- Candles and incense
- Wood-burning fireplaces
- High-heat frying and broiling
- Aerosol sprays
- Strong chemical cleaners
- Vacuuming with equipment that lacks suitable filtration
Check Outdoor and Indoor Air Quality First
Smoke levels can change throughout the day. Do not rely only on visibility, odor, or the color of the sky when deciding whether to open your home.
Check the Outdoor AQI
Use AirNow.gov or local government alerts to check the Air Quality Index before opening windows, exercising outside, or switching on a ventilation system to bring in outdoor air. The AQI indicates how clean or polluted the outdoor air is and whether associated health effects may be a concern.
As a practical guide:
- When the AQI is low, brief ventilation may be appropriate if the outdoor air is cleaner than the air inside.
- When the AQI is elevated, keep the home closed and increase filtration.
- When the AQI is very high or hazardous, minimize exposure and follow local public-health and emergency guidance.
The AirNow Fire and Smoke Map can also show nearby smoke, fine-particle readings, and monitoring locations.
Measure What Is Happening Inside
An indoor PM2.5 monitor can help confirm whether your protective steps are working. You can use one to:
- Track changes in indoor particle levels
- Compare conditions before and after closing windows
- Measure the effect of an air purifier
- Identify spikes from cooking, candles, or outdoor air intrusion
- Compare indoor air with current outdoor readings
Explore indoor air-quality monitors and testing products to better understand conditions inside your home. Sylvane offers monitoring and testing tools for contaminants that may otherwise be difficult to detect.
Particle monitoring and allergen testing serve different purposes. A PM2.5 sensor provides real-time particle readings, while allergen tests can help identify specific environmental triggers.
Create a Clean-Air Room
A clean-air room is a designated space where household members can spend time when smoke levels are elevated. Its purpose is to keep particle concentrations lower than in the rest of the home.
The EPA recommends closing the room’s windows and doors, avoiding particle-producing activities, and using a portable air cleaner when available.
Choose the Best Room
Look for a room that:
- Has few exterior doors and windows
- Can be closed off from other areas
- Is large enough for the people using it
- Has access to safe cooling
- Does not contain a fireplace or unvented gas-burning appliance
- Has space for a portable air purifier
A bedroom or interior living area is often a practical choice.
Set Up the Room
Close the windows and doors, seal major drafts, and run a correctly sized air purifier continuously. Keep cooking, smoking, candles, and other particle-producing activities elsewhere.
When possible, monitor the room’s PM2.5 levels. Keep essential medications, water, phone chargers, and other supplies nearby so occupants do not need to move repeatedly through the home.
Use an Air Purifier to Remove Smoke Already Inside
Having a tightly sealed home will limit the amount of pollution entering your home, but you will still need a way of removing any airborne particles that do make their way inside.
Typically, a portable or whole-home air purifier is the best tool for this task.
Look for HEPA Particle Filtration
Because wildfire smoke contains extremely small particles, air purifiers with high-efficiency particle filtration should be a priority.
Look for:
- True HEPA filtration
- Strong airflow
- Coverage appropriate for the room
- Multiple fan speeds
- Controls that support continuous operation
Run the purifier at a higher speed during active smoke events when noise and comfort allow. Higher fan speeds and longer operating times generally increase the amount of air that passes through the filter.
HEPA filtration primarily addresses particles. Do not assume every HEPA air purifier will also remove gases or persistent smoke odors.
Add Carbon Filtration for Odors and Gases
Activated carbon complements HEPA filtration by adsorbing some gaseous pollutants and smoke odors.
Thin carbon sheets may provide light odor reduction. Air purifiers containing larger quantities of carbon are generally better suited to recurring smoke odors or chemical concerns.
Carbon does not replace HEPA filtration. A smoke air purifier should provide effective particle filtration first, with carbon filters for odor and gas control as secondary priorities.
For model recommendations and additional sizing guidance, review the best air purifiers for wildfire smoke, Sylvane’s air purifier buying tips, and the air purifier FAQ.
Keep Filters Ready Before Wildfire Season
Filters may collect particles more quickly during prolonged smoke events. As a filter becomes heavily loaded, airflow and cleaning performance may decline.
During wildfire season:
- Check the purifier’s filter indicator.
- Inspect washable or vacuumable pre-filters more frequently.
- Follow the manufacturer’s cleaning instructions.
- Never wash a filter unless it is specifically labeled washable.
- Keep compatible replacement filters on hand.
- Replace filters based on their condition and manufacturer guidance, not only the calendar.
Shop air purifier replacement filters, including HEPA, carbon, and combination filter sets for multiple brands.
For ongoing care instructions, see these air purifier maintenance tips.
What to Do When the Outdoor Air Improves
First, check the current outdoor AQI. When an indoor monitor is available, compare outdoor and indoor PM2.5 readings. Ventilate briefly only when the outdoor air is cleaner than the indoor air, and continue running your air purifiers during and after ventilation.
After an extended smoke event:
- Inspect purifier and HVAC filters.
- Wipe hard surfaces with damp cloths.
- Use a damp mop or HEPA-filtered vacuum where appropriate.
- Avoid dry sweeping ash or settled particles.
Note: Keep in mind that ash can become airborne again during cleanup, and ash from burned structures may contain more hazardous material than forest ash.
When Staying Home May Not Be the Safest Option
Wildfire smoke can affect anyone, but children, older adults, pregnant people, and people with asthma, COPD, heart disease, or other chronic conditions may face greater risks. Smoke exposure can cause coughing, wheezing, eye irritation, difficulty breathing, and other symptoms.
Follow local emergency instructions and contact a medical professional about health symptoms or individual risk factors. If your home cannot maintain cleaner indoor air, consider temporarily relocating to a designated cleaner-air shelter or another building with effective filtration.
Wildfire Smoke Preparedness Kit
Prepare these items before smoke reaches your area:
- Portable HEPA air purifier
- Spare HEPA and carbon filters
- Indoor PM2.5 monitor
- Weatherstripping and temporary sealing supplies
- Properly fitting N95 respirators
- Essential medications
- HVAC filters approved for your system
- Local emergency and AQI apps
- Damp cleaning cloths and disposable gloves
Purchasing filters and air-cleaning equipment in advance can be especially important because supplies may become difficult to find during a widespread wildfire or wildfire smoke event.
Cleaner Indoor Air Starts With Preparation
When it comes down to it, keeping wildfire smoke and smog out of your home requires a three-tiered approach:
- Keep as much polluted outdoor air outside as possible.
- Filter any particles and odors that enter the space.
- Consistently monitor conditions and maintain your equipment.
One big key is to prepare before the next wildfire smoke alert. Explore Sylvane’s smoke air purifiers for particle and odor filtration, shop replacement filters for your current model, or use indoor air-quality monitors and testing products to see how conditions change inside your home.
For personalized product guidance, call 1-800-934-9194 to speak with a Sylvane product expert.
