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Wildfire season is unavoidable unless you plan on moving away. Since it occurs every year, the effects can be devastating. Some homes and businesses burn to the ground, but perhaps more importantly, it can deliver unhealthy air conditions across the country. Local officials may advise people to stay indoors, but even if you do, some of the smoke from the outside can enter to make your space unhealthy. With no apparent solution, it begs the question, ‘do air conditioners filter wildfire smoke?’.

Consequences of Wildfire

If you’re located close to a wildfire, the heavy smoke and ash pose a considerable threat to your safety and health. Houses that are slightly further away will experience smoke entering their homes. The problem with smoke is it contains a complex mixture of gases and tiny particles that are victims of the flame, such as wood and other materials. Those minute particles are the culprits that can affect your eyes and respiratory organs. Additionally, breathing in these toxins can trigger chronic heart and lung disease. If you’re lucky enough to be free from comorbidities, you won’t be at significant risk with a little smoke inhalation. However, it’s best to avoid taking in any smoke.

Wildfire’s Impact on Air Quality

The outdoor air, tainted with burnt particles in the form of smoke, can enter your home through open windows and doors, bathroom or kitchen fans that are meant to vent out the air from inside, the air conditioning system, and cracks or gaps in the walls or ceilings of your property.


Wildfires can impact your indoor air quality in several ways, depending on your distance from the fire. If the fire is close to your house, it’s advisable to evacuate as the flames can quickly spread and engulf your home. If the fire is close but not enough to harm your home, the smoke may enter making it difficult for you and others to breathe. Additionally, the build-up of smoke reduces visibility to almost zero, making it impossible to act when it’s too late. If you’ve heard of a wildfire that’s originated thousands of miles away, the chances of heavy smoke affecting your indoor air quality are minimal. Monitor the situation and stay informed.

Do Air Conditioners Filter Wildfire Smoke?

The short answer to the question is yes. If the area you live in is prone to wildfires, you can prepare adequately before the season begins. One route you can take is acquiring a portable air cleaner or a high-quality air conditioner filter. If you decide to pursue the latter, ensure that the HVAC filter has a high Minimum Efficiency Reporting Value (MERV) rating, usually higher than ten. The higher the number, the better the filter at removing contaminants. Filters also range in thickness from one to five inches. Try changing your filter more frequently during wildfire season as they can become dirty faster than usual.

You can inspect the filter to determine if it’s too dirty to perform at its best. A degradation in airflow is a sign that the filter needs replacing, and you can purchase them in packs at a local store or online. We advise speaking to an HVAC technician to identify the highest efficiency filter for your particular system.

Adjusting Your Air Conditioner to Keep Wildfire Smoke Out

If you have an air conditioner, it’s worth understanding its functions by exploring the system or asking your local HVAC contractor. With a central HVAC system, find out if it contains a fresh air intake. During the fire, you’d need to adjust the system to recirculate mode. Ensure that the filter is the correct size and that it fits comfortably in the filter slot.

Avoid using an evaporator cooler when there’s smoke coming through your property, as it may add to the problem. Window air conditioners and fans are better options in this scenario.

With a window air conditioner in place, you’d have to determine its proximity to the exterior air damper. If you can’t close the damper during a wildfire, you’d have to turn to other cooling sources. Additionally, ensure that the seal between the air conditioner and the window is tight with no leakages.

If you own a portable air conditioner that must run its vent out through the window, you shouldn’t use it during a fire and smoky conditions. Smoke from the outside will enter, causing further problems for you. Instead, look at window air conditioners of fans in this instance.

Other Steps to Take

Aside from using High-Efficiency Particulate Air (HEPA) filters, you can employ these techniques to assist your air conditioner:

  • Close all doors and windows.

  • Avoid burning candles or incense.

  • Try not to use gas, wood-burning, or propane furnaces and stoves.

  • Don’t spray aerosol products.

  • Avoid strenuous activity to save your breath.

After the wildfire, heavy winds can release ash into the air to compromise air quality. People with heart or lung health issues shouldn’t handle the clean-up. However, you can sweep it away gently using a broom and avoid skin contact with ash. Don’t forget to speak to your local HVAC technician for advice on preparing your air conditioner to filter wildfire smoke.