Prepare Your Home Before the 2026 Fire Season

Getting ready early reduces stress and exposure when smoke arrives. Stock the essentials, plan your clean room, and tune your filtration.

• Buy appropriately sized portable air purifiers with True HEPA filters (or HEPA + activated carbon). True HEPA is a filtration standard that captures at least 99.97% of 0.3-micron particles, crucial for PM2.5-rich smoke, per guidance on wildfire particles and indoor controls from TSI’s wildfire and IAQ overview.
• Map out a clean room where household members can retreat during heavy smoke—typically a bedroom or main living room you can easily close off and filter intensively.
• Expect faster filter loading during smoke events and buy spares; pre-filters and HEPA media can saturate days to weeks sooner than usual during severe smoke, per EPA clean-room guidance.
• Add weatherstripping, door sweeps, painter’s tape, and spare MERV 13+ HVAC filters to your kit.

Wildfire Prep Essentials

Item	Why it matters	Notes
True HEPA air purifier	Removes fine smoke particles quickly	Size by CADR; run on high during events
HEPA + activated carbon filter	Adsorbs gases and smoke odors	More carbon mass = better VOC/odor control
Extra HEPA/pre-filters	Smoke loads filters rapidly	Replace as soon as airflow drops or odors linger
Weatherstripping/door sweeps	Reduces smoke infiltration	Focus on exterior doors and leaky windows
Painter’s tape/film	Temporary sealing for gaps	Do not block exits
MERV 13+ HVAC filters	Captures PM2.5 in recirculation	Check fit and system compatibility
Box fan + MERV 13 filter	DIY backup if purifiers are scarce	Follow EPA safety tips; monitor for heat

Monitor Outdoor and Indoor Air Quality Continuously

Use real-time data to decide when to seal up, filter harder, or briefly air out.

• Check outdoor AQI on trusted government sources and apps; focus on PM2.5 during wildfires. The Air Quality Index is a color-coded system for outdoor pollution—higher numbers mean worse air.
• Add a low-cost indoor PM2.5 monitor to catch indoor spikes from cooking or infiltration.
• When AQI is unhealthy (over 150), keep windows and doors closed, switch HVAC to recirculate, and run purifiers on high; limit outdoor activity among sensitive groups per EPA’s wildfires and indoor air quality guidance.
• If you have a smart thermostat, set the fan to On (or use continuous circulation) to pass more indoor air through filters when outside air worsens.

Create and Maintain a Clean Room for Safe Indoor Air

A clean room gives you a refuge of low particle levels during smoky periods. The EPA’s clean-room guide recommends placing air purifiers where people spend the most time and notes filters may need replacing more often during wildfire smoke events.

How to set up and run a clean room:

1. Choose the room you use most (bedroom or main living area).
2. Close windows and doors; seal obvious gaps around frames and under doors. Do not block exits.
3. Place a portable True HEPA purifier in the room, with a few feet of clearance, and run it continuously on the highest practical speed.
4. Turn off systems that pull outside air; avoid kitchen/bath exhaust fans that depressurize and draw smoke indoors.
5. Minimize indoor particle sources: no smoking or candles; cook with lids and low heat; keep pets groomed; vacuum only with a HEPA-equipped machine.
6. Enter/exit the room infrequently and keep doors closed to maintain clean conditions.

Choose and Use the Right Air Purifier for Smoke

Picking the correct unit—and using it correctly—is one of the highest-impact steps you can take.

• Size by CADR: A simple rule of thumb is to match Clean Air Delivery Rate (CADR, in cubic feet per minute) roughly to the room’s square footage for rapid particle reduction. CADR is a standardized score indicating how quickly a purifier removes pollutants—the higher the CADR, the faster it works.
• Prioritize True HEPA for particles and a substantial activated carbon stage for smoke gases and odors. Heavier carbon beds generally improve VOC removal and odor control, as explained in an overview of gas-phase filtration for wildfire smoke.
• Avoid air cleaners that intentionally generate ozone; official guidance cautions against ozone-producing devices.
• Consider noise, energy use, and long-term filter costs alongside performance.

Optimize Filtration and Airflow During Smoke Events

Operation matters as much as the hardware.

• Run portable purifiers continuously on the highest practical fan speed during smoke events; higher airflow delivers faster cleanups.
• Set central HVAC to recirculate or Fan On. If your system can handle it, upgrade to MERV 13 or higher to capture more PM2.5. Oregon State University’s wildfire indoor air guidance also recommends continuous fan operation to increase filtration passes.
• Use multiple purifiers for large or open spaces, or closed-door bedrooms so each zone has adequate CADR.
• Maintain clearance around intakes and avoid pointing purifiers directly out open doors where they could push smoke in.
• Replace filters more often when smoke is heavy—sometimes every few days to weeks—if airflow drops, odors persist, or the filter darkens quickly.

Room Size vs. Recommended CADR (CFM)

Room size (sq ft)	Typical ceiling (8 ft)	Target CADR (cfm)
100–150	Small bedroom/office	100–150
200–300	Bedroom/den	200–300
350–450	Living room	300–450
500–700	Large room/open plan	400–700
800–1,000+	Great room/studio	600–1,000+ (or multiple units)

Use DIY and Supplemental Solutions When Needed

If supplies are scarce or budgets tight, DIY filtration can help.

• Build a DIY box-fan filter (often called a Corsi–Rosenthal box) using a new, UL/ETL-labeled fan (2012 or newer) and high-MERV filters. Avoid extension cords, keep the fan stable, and check for warm odors or overheating. EPA research on DIY air cleaners shows these setups can significantly reduce indoor particle levels, though dedicated HEPA units generally perform more consistently.
• Replace filters frequently during smoke; monitor airflow and noise changes.
• Supplemental habits that reduce indoor pollution load:
  • Remove shoes and bag smoky clothing at the door.
  • Cook less, use lids, and avoid high-heat frying.
  • Skip candles, incense, and indoor smoking.
  • Coordinate with neighbors on clean-room setups for vulnerable residents.

Seal and Ventilate Strategically During Smoke Episodes

Balance keeping smoke out with refreshing indoor air when conditions allow.

• Seal obvious gaps around windows, doors, fireplace dampers, and through-wall AC sleeves with weatherstripping and tape; never block exits.
• Ventilate (air out) only when outdoor AQI meaningfully improves—ideally after smoke plumes pass—and then re-seal and return to recirculation. The EPA’s wildfire IAQ page outlines when to close up and when to safely ventilate.
• If ventilation is unavoidable (e.g., for cooling), use MERV 13+ filters on HVAC intakes or evaporative coolers to reduce PM2.5 ingress.

Frequently Asked Questions

Conclusion

Wildfire smoke is unpredictable, but your response doesn’t have to be. Prepare early, size and stage the right HEPA purifiers, monitor outdoor AQI and indoor PM2.5, and lean on a well-sealed clean room when conditions worsen. During events, keep windows and doors closed, run filtration on high, minimize indoor particle sources, and replace filters as needed; when air improves, ventilate briefly and re-seal. With these habits and tools in place, you can keep indoor exposure low throughout fire season and help protect everyone in your home.