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Wildfire season in British Columbia is no longer a once-in-a-decade event—it’s annual, it’s longer than ever, and for residents of Cranbrook and the East Kootenays, the impact is personal.

Even when the fires are hundreds of kilometres away, smoke often blankets the entire region. The thick haze rolling down Baker street isn’t just from your deleted diesel truck, it is from the burning of wood, plastics, and chemicals. Not only unpleasant to look at or smell—it contains microscopic particles that can enter your lungs, bloodstream, and even your brain. For families with children, seniors, pets, or anyone with asthma or respiratory concerns, keeping indoor air clean is no longer optional.

The good news: there’s plenty you can do right now to protect your home and your health—before the air turns grey.

Why Wildfire Smoke Is So Harmful—and So Persistent

When wildfires burn, they release a combination of gases, ash, and PM2.5 particles (particulate matter smaller than 2.5 microns in diameter). These particles are tiny enough to:

• Pass through basic HVAC filters
• Enter through cracks around windows, doors, vents, and chimneys
• Settle deep into your lungs, bypassing your body’s natural filtration
• Cause or worsen asthma, chronic bronchitis, heart disease, and even stroke

Interior BC communities like Cranbrook are often affected for weeks at a time. The effects aren’t limited to air quality either—smoke damage can cling to furniture, drywall, curtains, electronics, and HVAC systems long after the air looks clear again.

Step 1: Seal Windows and Doors

Your home’s envelope is your first line of defence. Start with a smoke-tight seal:

• Replace worn or cracked weatherstripping around exterior doors
• Apply silicone or caulking to any gaps in door frames or window trims
• Use foam gaskets behind wall outlets and switch plates on exterior walls
• Add door sweeps to exterior and garage doors

Pay extra attention to basement windows and older sliders—these are often overlooked but can let in a surprising amount of outdoor air during a heavy smoke event.

Step 2: Upgrade Your Furnace Filter—Properly

If your furnace or air handler is running, it’s likely pulling outdoor air inside. Basic fiberglass filters—like the $5 ones at the hardware store—won’t do anything to catch smoke particles or odours.

Instead, install:

• A MERV 13 or higher furnace filter (many homes can handle MERV 13 without reducing airflow)
• Or a carbon/charcoal-embedded filter that can absorb smoke odours and VOCs as well as particulates

Check with your HVAC contractor before installing high-MERV filters in older systems, as they can restrict airflow if improperly matched.

Pro Tip: During heavy smoke periods, change filters every 2–3 weeks. This is one of the most affordable ways to protect your family’s breathing space.

Step 3: Add HEPA Air Purifiers—Before the Rush

A quality HEPA purifier removes 99.97% of airborne particles down to 0.3 microns—which means it can trap wildfire smoke particulates.

Place purifiers in the rooms where you spend the most time:

• Bedrooms (especially for children or people with asthma)
• Living room or home office
• Any space with limited ventilation

Expect to pay:

• $200–$300 for small room units
• $500–$1,000+ for large-space systems with activated carbon filters

Important: These units are often sold out during wildfire season. Retailers across Cranbrook, Invermere, and Fernie routinely sell out of HEPA units in late July and August.

That’s why WINMAR® Kootenay offers a professional rental fleet of air scrubbers and filtration systems. Contact us early in the season to reserve one—or several—for your home or business.

Step 4: Use Recirculation Mode on HVAC Systems

Your air conditioner or forced-air furnace may be constantly pulling fresh outdoor air inside—unless you tell it not to.

Set your thermostat to recirculate. This means the system will continue to move air through your filter and ducts without bringing in new smoke-laden air from outside.

On older systems, this might be a toggle switch. On newer thermostats, it’s often found under “Fan Settings” or “Airflow Options.”

If you have an HRV or ERV system, turn it off during high-smoke days unless it’s equipped with high-grade filtration.

Step 5: Close the Fireplace Damper and Block Passive Vents

Your fireplace damper might seem insignificant—especially if you haven’t had a fire in months—but it’s a direct pathway from outside to inside. Smoke under pressure can flow into your home through that opening like water through a hose.

Before wildfire season:

• Close and seal the damper
• Block any fresh air intake vents (if unused or connected to an old wood stove)
• Check old dryer vents, HRV inlets, or wall penetrations for backflow dampers

If you live in an older home, a smoke test from an air quality professional (or even incense and a flashlight) can help you identify air leak hotspots.

Step 6: Designate a Clean Air Room

Pick one room in your home to become a “clean zone.” Ideally:

• It should be sealed tightly
• Contain no fireplaces, combustion appliances, or open vents
• Be equipped with a dedicated HEPA purifier or air scrubber
• Remain closed to traffic when smoke is present

This becomes your breathing room—especially important for children, elderly family members, or people with chronic conditions.

Add a portable humidifier if you want to keep relative humidity around 40%—this can help reduce respiratory irritation caused by dry, smoky air.

Step 7: Consider a Professional Indoor Air Quality (IAQ) Assessment

If your home has previously experienced smoke infiltration—or if you want to make sure you’re truly prepared—WINMAR® Kootenay can perform a full indoor air quality inspection.

We offer:

• Air quality monitoring for PM2.5, VOCs, and temperature/humidity balance
• Post-smoke decontamination of ductwork, drywall, and soft contents
• Professional-grade air scrubber rentals

For more advice, see also: Mitigating Forest Fire Smoke in Your Home – WINMAR® Nelson

The Most Important Lesson: Don’t Wait

Wildfire smoke events don’t always come with a warning. Wind shifts, dry lightning, and distant fires can blanket the East Kootenays in smoke within hours.

Unfortunately, this is also when most residents begin looking for:

• HEPA filters
• Replacement furnace filters
• Air purifiers
• Rentals or professional help

By then, inventory is low—or gone.

The time to prepare is now.

If you need help sealing your home, planning your filtration setup, or booking a pre-smoke IAQ inspection, reach out to WINMAR® Kootenay today.