How to Optimize Your AC for Wildfire Smoke

There are plenty of signs that summer has arrived in Oregon. Longer days, warmer temperatures, the AC finally earning its keep… and, unfortunately, wildfire smoke.

When the sky turns hazy and the familiar smell of smoke settles into the air, most of us know to limit our time outside. What’s easier to forget is that closing the front door doesn’t automatically leave all that smoke on the other side of it. Fine particles can still make their way indoors, which means the way you use your air conditioning and filtration system can make a real difference in the air inside your home.

The good news? Your HVAC system can be part of your defense. You just need to know how to use it.

First, What Exactly Are We Trying to Filter?

Wildfire smoke isn’t simply the smell of something burning miles away. It contains a mixture of gases and extremely small particles, including fine particulate matter that can travel deep into the lungs. Exposure can cause coughing, irritated eyes, headaches, difficulty breathing and other symptoms, and it can be especially concerning for children, older adults, pregnant people, and those with heart or lung conditions.

That’s why improving indoor air during a smoky stretch isn’t just about making the house smell better. It’s about reducing the amount of smoke particles your family is breathing.

And that brings us to the little rectangle sitting inside your HVAC system.

Your Filter Rating Matters More Than Ever

Not every HVAC filter is designed to do the same job. In fact, some inexpensive filters are primarily intended to protect the HVAC equipment itself by catching larger debris. They may catch things like dust and lint, but they’re not necessarily effective at capturing the much smaller particles found in wildfire smoke.

This is where you’ll want to pay attention to the filter’s MERV rating, or Minimum Efficiency Reporting Value. The higher the rating, the better the filter is at capturing smaller particles.

During wildfire smoke events, the EPA recommends a MERV 13 filter, or the highest-efficiency filter your particular HVAC system can safely accommodate. That last part matters. A higher number isn’t automatically better if your system isn’t designed for the additional airflow resistance.

In other words, don’t walk into the store, find the filter with the biggest number and declare yourself the winner.

If you’re unsure what your system can handle, ask an HVAC professional. And if you’d like a refresher on choosing and changing filters in general, our HVAC Filter Guide for Oregon City’s Seasonal Changes is a great place to start.

Put Your AC to Work—Without Inviting the Smoke Inside

When it’s hot and smoky outside, turning off the air conditioning and opening the windows isn’t exactly a great Plan B. Thankfully, you can continue using your AC while taking steps to reduce the amount of outside smoke entering your home.

Keep windows and doors closed as much as possible. If your HVAC system has a fresh-air intake, close it during periods of heavy smoke or switch the system to recirculate mode. The goal is to cool and filter the air that’s already inside instead of continually bringing smoky outdoor air into the house.

You can also run your HVAC fan more frequently during a smoke event. Your filter only cleans air while air is actually passing through it, so setting the fan to “On” rather than “Auto” can increase filtration during especially smoky periods.

There’s one catch: all that filtering means your filter is doing a lot more work than usual.

Don’t Assume Your Normal Filter Schedule Still Applies

If Oregon’s wildfire smoke is heavy for several days or weeks, don’t wait for your normal filter-change reminder to pop up.

Take a look at it.

A filter that’s normally good for several months may become dirty much faster during a smoke event. As particles accumulate, airflow can become restricted and your HVAC system has to work harder to move air through the house; the exact opposite of what we want when your AC is already working hard through summer temperatures.

Keep an extra filter or two on hand during wildfire season and check the one in your system periodically. If it’s noticeably dirty or heavily soiled, it’s time for a change.

What About Portable Air Purifiers?

Your central HVAC system doesn’t have to do all the work. A properly sized portable air cleaner can provide another layer of filtration, particularly in the rooms where your family spends the most time.

Look for a unit designed for the size of the room you’re using it in and avoid air cleaners that intentionally produce ozone. During especially bad smoke events, some families choose one bedroom or living area as a “cleaner air room,” keeping the doors and windows closed and using additional filtration there.

Think of it as giving your HVAC system a teammate rather than asking it to play the entire game by itself.

Your AC Can’t Control the Wildfire. It Can Help Control What’s Happening Inside.

We can’t do much about which direction the wind blows or when wildfire smoke decides to settle over Oregon. But we can make smarter decisions about the air inside our homes.

Using the right filter, keeping smoky outdoor air from being pulled into the system, running your fan more frequently when needed, and checking your filter throughout a smoke event can all help your HVAC system do a better job of protecting your indoor environment.

And if you’re staring at your filter thinking, Is this actually the right one?—you don’t have to guess.

At Chase Heating & Cooling, we’re happy to help you determine what your system can safely accommodate and make sure your AC is ready to handle both the heat and the smoke.

Because on a smoky Oregon summer day, coming home should feel like getting away from it; not bringing it inside with you.