Reduce wildfire smoke with your HVAC system



Wildfire smoke is nasty. We're talking about thousands of individual compounds, many of them toxic and small enough to enter your bloodstream.


Here we walk through a few of the best ways to protect your home from wildfire smoke with heating, ventilation, and air conditioning (HVAC). If you have a central air conditioner, heat pump, or gas furnace, you'll find tips to get cleaner air by using your existing system. You can also learn about more advanced ventilation systems, like a whole home air filter and heat recovery ventilator, both of which provide hospital grade air filtration for you and your family. The bottom line - You have a lot of options to breath easier during wildfire season.


Learn more about HVAC systems we install in Portland and HVAC systems installed in Bend, Oregon. If you’re ready to schedule a free estimate for a new system, please give us a call at 866.827.5774 or self-schedule online in Portland Metro or Central Oregon. Each estimate includes a detailed breakdown of costs, cash incentives and available tax credits.


What's in wildfire smoke?

Wildfire smoke is a shifting blend of gases and particles, including carbon dioxide, water vapor, carbon monoxide, hydrocarbons and other organic chemicals, nitrogen oxides and trace minerals. 

What worries doctors most is the particulate matter in smoke, the tiny bits of feathery ash and dustlike soot, much of it invisible to the eye. They're especially worried about particulate matter less than 10 microns wide, known as PM 10. (By comparison, a human hair is about 60 microns wide). They also dread the subset known as PM 2.5, for particulate matter less than 2.5 microns wide.

These tiny particles travel deep into the lungs and the smallest ones can even enter the bloodstream. The smallest particles are also the lightest, and can travel vast distances on the wind.

The particles first damage the body simply by getting inside of it – triggering inflammatory reactions that themselves can trigger breathing difficulties, heart attacks and even strokes. Within a few days of smoke exposure, damaged lungs can succumb to bronchitis or pneumonia. In pregnant women, exposure to particulates has been associated with premature birth and low birth weight in infants.


Do you run a higher risk of cancer or other chronic health conditions (e.g. heart disease) from short-term exposure to wildfire smoke? In general, the long-term risks from short-term smoke exposures are low. Short-term elevated exposures (i.e. over days to weeks) to carcinogens found in wildfire smoke are also small relative to total lifetime exposures to carcinogens in other, more common combustion sources.

Who's at the greatest risk?

  • People who have heart or lung diseases, like heart disease, chest pain, lung disease, or asthma, are at higher risk from wildfire smoke.

  • Older adults are more likely to be affected by smoke. This may be due to their increased risk of heart and lung diseases.

  • Children are more likely to be affected by health threats from smoke. Children’s airways are still developing and they breathe more air per pound of body weight than adults. Also, children often spend more time outdoors engaged in activity and play.

"Wildfire smoke can be a big problem for sensitive populations, especially people with asthma," says Jeff Mounts with AirAdvice.  "The particulate levels we've seen this season are enough to send people to the ER." 

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First, it's important to understand the air quality in your home.

Check out, a stellar resource from the U.S. EPA. When you enter your zip code, you'll see how clean or polluted your outdoor air is, along with associated health effects that may be of concern. Google (as usual) provides a shortcut - When you search for "air quality portland" or "air quality bend", Google pulls data from and presents it at the top of your screen.

If you want diagnostics on your home in particular, we offer AirAdvice testing to measure 6 common indoor air quality concerns: (1) particulate matter, (2) chemical off-gassing, (3) carbon dioxide, (4) carbon monoxide, (5) temperature, and (6) humidity. Here's a report from a test conducted last week at a home in SW Portland. The spike in particulates is the result of leaving a front door open.

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Avoid making your indoor air worse.

Start by shutting your windows and doors if you're advised to stay inside. Then avoid activities that increase indoor pollution, like smoking, burning candles, and using a gas stove. You'll also want to limit your vacuum use (unless you have a vacuum with a HEPA filter) to avoid stirring up particles that are already inside your home.

If you don't have air conditioning and you depend on open windows and doors for ventilation, it can be dangerous to shut yourself inside. There's an increased risk of heat stress. Older people and others in frail health are more likely to experience heat exhaustion or heat stroke, both of which can have serious consequences. We strongly recommend air conditioning for hot days when you're advised to stay inside. If air conditioning isn't feasible for you at this time, it's best to stay with friends, family or neighbors who have an AC system.

Get the most from your heating or cooling system

Make sure you have the right filter.

Start by making sure you have a fresh filter for your system with a backup ready to go. To choose the right filter, consider the Minimum Efficiency Reporting Value (MERV) rating. Filters that are MERV 13-16 are expected to reduce indoor particulars as much as 95%. Filters with a High Efficiency Particulate Air (HEPA) rating, (or MERV 17-20) will reduce particulates in your home even more. If you have a ductless heat pump, we recommend a two stage catechin filter, which traps particulates as well as germs, bacteria, and viruses in your home.

You might also consider an air filter with activated carbon. Carbon air filters are designed to filter volatile organic compounds (VOCs) from gases in your home through a bed of activated carbon (also called activated charcoal).

Circulate and filter air through your HVAC system.

If you have a cooling system, like central air conditioning, a heat pump, or a ductless heat pump, simply use your system as you normally would. By default, these systems re-circulate air in the home, so they filter air without pulling in additional particulates from outdoors. If you have a heating system, like a gas furnace, or a cooling system that you're not currently using, we recommend turning the fan on at your thermostat. This will re-circulate air and help to filter out particulates.


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Aprilaire Electronic Air Purifier Model 5000

When you install an air purifier, the air in your duct system runs through electrostatic HEPA filter. This hospital grade filter eliminates viruses and ultra-fine particles as small as 0.1 micron (120 times smaller than a human hair) from the air in your home. We recommend the Aprilaire Electronic Air Purifier Model 5000, which has an estimated price of $1K to $1.5K.

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Broan Heat Recovery Ventilator (HRV)

A heat recovery ventilator (HRV) goes beyond just filtering the air that comes into your home. An HRV removes stale air from your home and replaces it with a continuous stream of fresh air. For the best possible air quality, we recommend the Broan HRVH100S. Two things set this system apart: First, it uses a HEPA filter to remove fine particulates before they enter your home. Second, the system is highly efficient. It transfers the heat or coolness from your stale exhaust air to preheat or precool your fresh incoming air. The estimated price is between $2.5K and $3K.


Wildfire smoke should be taken seriously, especially for sensitive populations (e.g. children and people with asthma). It's important to pay attention to the quality of the air near your home. Check out When you're advised to stay indoors, keep the windows and doors shut and avoid doing things that make air quality worse, like smoking or burning candles.

If you have a central air system, make sure you have a fresh air filter with a high MERV rating as well as activated carbon, and keep a spare ready to go. You can filter air in your home by running your cooling system (AC, heat pump, or ductless heat pump). If you have a heating system (gas furnace) or a cooling system you're not currently using, turn the fan on at your thermostat. For the best possible air quality in your home, consider installing an electrostatic whole home air filter or heat recovery ventilator, which provides you with a continuous stream of fresh air.

Bill HoelzerGreenSavers