How to Keep Your Home's Air Clean During Wildfire Smoke: A Complete Guide

The eerie orange glow of the sun through thick wildfire smoke might seem like a distant concern—until the haze settles over your city for days. When hazardous air quality warnings cover multiple states, the tiny particles suspended in the air become a serious health threat.

According to environmental health experts, wildfire smoke can cause a range of short-term and chronic health issues. But here's the reality: staying indoors alone isn't enough. You need to actively protect your home's air quality. In this guide, we'll share expert-approved strategies to keep your family safe when wildfire smoke and poor air quality strike.

 

1. Use Your Central Air Conditioning System Properly

If you have central air conditioning, you already have your home's first line of defense against wildfire smoke. But running it correctly is critical.

Step 1: Replace Filters with High-Grade Options

Don't just replace your HVAC filters—upgrade them. Filters rated MERV 13 or higher are ideal for trapping fine pollution particles. These are significantly more effective than standard filters at removing the tiny particles that cause health problems.

Make sure filters are replaced on schedule (typically every 1-3 months, depending on air quality). During heavy smoke events, you may need to replace them more frequently.

Step 2: Set Your System to Recirculate

Close any vents that pull air from outside. Setting your air to recirculate means it keeps filtering the same indoor air rather than pulling in contaminated outdoor air. This is a crucial step that many homeowners overlook.

Step 3: Run Your System Continuously

The University of Oregon's Center for Wildfire Smoke Research recommends running your HVAC system's fan through the entire smoke event—not just when cooling. Continuous air circulation ensures maximum filtration throughout the day and night.

Pro Tip: Invest in high-quality MERV 13 filters now, before wildfire season arrives. Having them on hand ensures you can upgrade quickly when air quality deteriorates.

 

2. Invest in a Portable Air Purifier (Or Build a DIY Version)

Central air isn't available in every home. If you don't have air conditioning, a portable air purifier is your next best option.

Commercial Air Purifiers:

Look for portable units specifically designed for air purification. Key features to check:

• HEPA filters: Designed to trap small particles and pollution
• No ozone generation: Some units produce ozone, which is itself a harmful air pollutant—avoid these
• Size appropriate to your room: Larger rooms need stronger purifiers

The Budget-Friendly DIY Alternative:

Here's something that might surprise you: DIY filters made by taping furnace filters to a box fan are just as effective as commercial air purifiers. In fact, the EPA has confirmed this.

What you need:

• Four 20-by-20-inch furnace air filters (rated MERV 13 or higher)
• One box fan
• Cardboard
• Duct tape

How to build it:

1. Tape the furnace filters to the sides of the box fan
2. Make sure the fan blows outward
3. Ensure the arrows on the filters point inward
4. Seal everything airtight with duct tape and cardboard

The EPA's website shows simplified versions using just one or two filters if you're on a tight budget. The cost? Around $30-50, compared to $100+ for commercial units.

"The good news is they really work," says Amy Kalkbrenner, an environmental epidemiologist at the University of Wisconsin-Milwaukee. "The basic message is that something is better than nothing."

3. Create a "Clean Room" in Your Home

If you can only afford one air purifier or want to maximize efficiency, create a designated clean room—a space where you and your family spend most of your time during heavy smoke events.

This might be:

• Your bedroom (for sleeping in clean air)
• A living room or family room (for daytime activities)
• A home office (if you work from home)

Position your portable air purifier or DIY box fan filter in this room. Keep the door closed to maintain air quality, and spend your time in this protected space during smoke emergencies. This strategy is particularly important for children, elderly relatives, and anyone with respiratory conditions.

 

4. Safely Use Window Air Conditioning Units

Window and portable air conditioners present a different challenge. Many window units and mini-split systems don't have filters capable of removing fine pollution particles.

The Problem:

Window AC units pull outside air into your home to function. If that outside air is filled with wildfire smoke, you're essentially inviting contamination inside.

The Solution:

If you use a window AC unit, combine it with an air purifier:

1. Run your window AC unit to manage heat (important—heat combined with smoke intensifies health risks)
2. Use a portable air purifier or DIY box fan filter simultaneously to clean the circulated air
3. Ensure your AC unit is well-sealed in the window frame to prevent outdoor air leakage

Important Note: "When smoke and heat occur together, the impacts on your health are even greater than when they occur by themselves," according to wildfire smoke researcher Jess Downey at the University of Oregon.

If you don't have AC: Seek refuge in air-conditioned public spaces—libraries, shopping malls, cooling centers—especially during peak heat and smoke hours.

 

5. Seal Your Home Against Outside Air

Think of sealing your home like weatherproofing for winter—you're blocking air leaks that allow contaminated outside air to enter.

Areas to seal during high smoke events:

• Door frames and thresholds
• Window edges and sills
• Gaps around pipes and electrical outlets
• Cracks in walls or foundations
• Air gaps in closets or crawl spaces

Materials you can use:

• Towels or draft stoppers under doors
• Weather stripping tape
• Caulk for larger gaps
• Plastic sheeting taped to windows

"Being from Chicago, I think you can liken it to trying to keep the cold air out," says Dr. Khalilah Gates, a lung doctor with Northwestern Medicine. "Any areas in which air can come in, consider sealing up those areas to reduce the amount that's coming into the home."

You don't need to seal everything permanently—just temporary measures during active smoke events can make a significant difference.

 

6. Avoid Indoor Burning and Combustion

Here's something most people don't think about: when wildfire smoke is present, burning anything inside your home makes air quality worse.

Avoid during smoke events:

• Candles and incense
• Fireplaces and wood stoves
• Gas stoves (use electric or microwave when possible)
• Smoking
• Grilling indoors

These activities add more fine particles to already-contaminated indoor air. Plan your meals ahead with simple, prepared foods that don't require cooking, or use a microwave instead.

 

7. Recognize Symptoms and When to Seek Help

Exposure to wildfire smoke can affect your body quickly. Know the warning signs:

Common symptoms:

• Shortness of breath
• Chest tightness
• Headaches
• Burning sensation in nose and eyes
• Coughing or wheezing

What to do:

If you experience mild symptoms, acknowledge that your body is responding to poor air quality. Move indoors immediately (or to a cleaner space), close windows and doors, and turn on your air purifier or AC system.

Seek emergency care if you experience:

• Wheezing or inability to catch your breath
• Severe chest pain or pressure
• Signs of respiratory distress

Dr. Gates emphasizes: "When you start to feel those symptoms and they're not severe, it's important to acknowledge, 'Oh, my body is responding to this. I need to move away from it. I need to move inside.'"

 

Prevention: Prepare Before Wildfire Season

Don't wait until smoke fills your sky to act. Prepare in advance:

Before wildfire season arrives:

• Stock extra MERV 13 or higher HVAC filters
• Test your central air system and have it serviced
• Purchase a portable air purifier (or gather supplies for a DIY filter)
• Seal obvious air leaks around doors and windows
• Identify your "clean room" and test your purification plan
• Check AC unit seals and functionality
• Create a smoke emergency kit with supplies

Taking these steps now means you'll be prepared when wildfire season strikes—and you won't be scrambling for sold-out filters or air purifiers when everyone else is doing the same.

The Bottom Line: Protect Your Home and Your Health

Wildfire smoke isn't just an inconvenience—it's a health threat. By maintaining your HVAC system, using high-quality filters, investing in air purification, and sealing your home against outside air, you create a safe sanctuary when hazardous air settles over your region.

The good news? You don't need expensive systems to make a difference. From upgraded MERV 13 filters to a DIY box fan setup, effective solutions exist at every price point.

Your family's health depends on the air they breathe. When wildfire season arrives, you'll be grateful you took these protective steps.

Prepare your home today—shop Cleantual's air quality and home protection products.