Yes, with the right setup and knowledge, your HVAC system can become your first line of defense against smoky air. The challenge is that standard AC filters weren’t really designed with wildfire smoke in mind. Most basic filters catch larger particles like dust and pet dander. But those tiny smoke particles? They slip right through.
Wildfire smoke is made up of tiny particles, about 30 times smaller than a human hair. Because they’re so small, these particles can get deep into your lungs when you breathe them in. This can cause problems for everyone (especially for kids, older adults), and anyone with asthma or other breathing conditions.
As HVAC experts serving the Pacific Northwest for years, we’ve seen firsthand how wildfire smoke affects our community. The hazy skies, the burning smell that seeps into everything, and the health concerns that come with breathing in all those tiny particles.
During heavy smoke days in Vancouver WA and the Portland OR Metro Area, you might notice scratchy throats, irritated eyes, and even headaches. Long-term exposure can lead to more serious health concerns. This is why you need a MERV filter rated 13 or higher.
What Is a MERV Rating (and Why Does it Matter)?
Minimum Efficiency Reporting Value (MERV) is a rating system that tells you how well an air filter captures particles of different sizes. The scale goes from 1 to 20, with higher numbers meaning the filter catches smaller particles.
Here’s where it gets important for smoke season: a standard home filter usually has a MERV rating between 1 and 4. That’s fine for catching dust bunnies and larger debris, but it’s not going to do much against those tiny smoke particles we talked about earlier.
A MERV 13 HVAC filter is generally considered the sweet spot for filtering out wildfire smoke. At this level, the filter can capture a significant amount of those fine particles that make smoke so harmful.
Can Any HVAC System Handle a MERV 13 Filter?
It depends. Not every HVAC system is built to handle higher-rated filters, and using the wrong filter can actually cause problems. Higher MERV-rated filters are denser because they have more fibers packed together to catch smaller particles. That density means air has a harder time passing through.
So if your HVAC system isn’t designed for that extra resistance, it has to work harder to push air through the filter. This can lead to reduced airflow, increased energy bills, and in some cases, damage to your system.
Older systems and some budget units may struggle with anything above MERV 8. On the other hand, many modern systems are built to accommodate MERV 13 or higher without any issues. The only way to know for sure is to check your system’s specifications or have a professional take a look.
How to Use Your AC as a Smoke Filter
Let’s say you’ve got a MERV filter for wildfire smoke installed, and you’re ready to tackle smoke season. There are still some important steps to make sure your system works as effectively as possible:
- Get a proper fitting filter. Gaps around the filter are like leaving a window cracked, and smoke particles will find their way through. When you install a new filter, check that it sits firmly in place without any spaces around the edges.
- Check on your fresh air intake. Many central HVAC systems have what’s called a fresh air intake, which is designed to bring outdoor air into your home for ventilation. If your system has a fresh air intake, you’ll want to learn how to close it or switch your system to “recirculate” mode. This tells your HVAC system to keep cycling the air that’s already inside your home instead of pulling in smoky air from outside.
- Run the fan continuously. On your thermostat, there’s usually an option to set the fan to “On” instead of “Auto.” When it’s set to “On,” the fan runs continuously, constantly cycling air through your filter even when the system isn’t actively heating or cooling. During smoky days, this helps remove particles from the air around the clock.
- Change filters more frequently. During smoke season, your filter is working overtime. Instead of following the standard replacement schedule, check your filter every couple of weeks during heavy smoke periods. If it looks dirty, replace it.
If your system can’t handle a high-efficiency filter on its own, don’t worry. There are other solutions that can get you the air quality you need without straining your equipment.
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What About Window and Portable AC Units?
Window air conditioners can help, but they require some attention. Many window units have an outdoor air damper that allows outside air in. During smoke season, you’ll want to close this damper completely. If your unit doesn’t have a closeable damper, you might need to limit use during the worst smoke days or consider alternative cooling options.
The seal between your window unit and the window itself also matters. Any gaps let smoky air seep in. Take a few minutes to check the seal and add weatherstripping or foam if needed.
Portable air conditioners are a bit trickier. Single-hose units actually create negative pressure in your home, which can pull smoky outdoor air in through cracks and gaps elsewhere in the building. If you have a single-hose portable AC, use it sparingly during smoke events. Two-hose units are better because they balance the air pressure, but you’ll still want to make sure the window vent kit seals tightly.
Other Solutions to Consider
- Get portable air cleaners or purifiers. These standalone units come with their own high-efficiency filters, often HEPA-grade, and can be placed in the rooms where you spend the most time. During smoke season, running a portable air purifier in your bedroom at night can make a real difference in how you feel the next morning.
- Add an ionizer. Ionizers work by releasing charged particles into the air. These charged particles attach to pollutants like smoke particles, making them heavier and easier to capture in your filter or causing them to settle out of the air onto surfaces where they can be cleaned up. Check out our ionizing air purifiers here and here.
- Upgrade your HVAC system. For some homeowners, the best long-term solution is upgrading to a newer HVAC system designed to handle high-efficiency filters. Modern systems often come with improved filtration capabilities built in. If your current system is aging and you’re facing costly repairs anyway, it might make sense to invest in equipment that can better protect your family during smoke season.
Steps You Can Take to Prepare for Wildfire Smoke Season
Don’t wait until the sky turns orange to think about your indoor air quality. There are steps you can take right now to prepare for the next smoke season:
- Get familiar with your HVAC system. Locate the filter, learn how to change it, and find out if you have a fresh air intake. If you’re not sure whether your system can handle a MERV 13 filter, now is the time to find out.
- Stock up on filters. During smoke season, high-efficiency filters can be hard to find as demand spikes. Having a few extra MERV 13 filters on hand means you’re ready when you need them.
- Consider having your HVAC system inspected by a professional. A technician can assess whether your system is ready for smoke season, recommend appropriate filter upgrades, and identify any issues that might affect performance. This is also a good time to discuss hybrid solutions like ionizers if you’re interested.
- Don’t forget about N95 respirators. When you do need to go outside during heavy smoke, these masks provide protection that your HVAC system can’t. Make sure you know how to use them properly. The mask needs to seal against your face to be effective.
Read more about wildfire smoke prevention here.
Your Partner in Indoor Air Quality
Living in the Pacific Northwest means accepting that smoke season is part of our summer reality. But it doesn’t mean you have to suffer through it.
If you’re unsure whether your current system is up to the task, or if you’re curious about upgrades that could help, we’re here to answer your questions. We’re committed to helping Vancouver WA and Portland OR families breathe easier.
Smoke season will come again. But this year, you can be ready. Contact us today to schedule an indoor air quality consultation and find out how we can help you and your family stay comfortable year-round.