Smoky Skies and Rising Bills: How to protect your home in Minnesota this summer
Your seasonal checklist for air quality, energy, and expenses
Wildfire smoke season is back, and this summer, the Minnesota Pollution Control Agency is forecasting 12 to 16 days of smoke impact across the state. For families with kids who have asthma, for older adults, and for anyone with a heart or lung condition, those are not just hazy days. They are days when staying inside matters.
Staying inside, however, only works if your home is doing its part to maintain good air quality. For most Minnesota homes, there is room to do better.
Closing your windows is not enough to protect from wildfire smoke
Most people assume that shutting the windows during a smoke event solves the problem. It helps, but the EPA has found that even with windows and doors closed, indoor PM2.5 levels (i.e., the fine particles in wildfire smoke that cause the most harm) can still reach 55 to 60% of outdoor levels.
Here is what surprises most people: your heating or cooling system might be pulling smoky outdoor air inside every time it kicks on. Most homes have a fresh air intake, a direct connection to the outside, or a heat recovery ventilator (HRV) that exchanges indoor and outdoor air. Both serve an important purpose most of the year. But during a smoke event, they can work against you.
Note: homes with natural gas heating appliances also rely on outside air for combustion, which adds another pathway for smoke to enter.
Even with windows and doors closed, indoor PM2.5 levels can reach 55–60% of outdoor levels.
Heat pumps improve indoor air filtration over traditional ducted A/C
A cold climate air source heat pump does something a traditional furnace or window AC unit does not — it runs for longer, steadier cycles. That means your air passes through the filter more often, which allows a high-quality filter to do its job best.
The EPA recommends upgrading to a MERV-13 filter during smoke events. Think of MERV ratings like SPF for sunscreen: the higher the number, the smaller the particles it blocks. A standard filter (MERV-8) catches dust and pollen but lets fine smoke particles through. A MERV-13 catches those too, and it fits the same slot as your current filter — you just swap it out when needed.
What to do during a smoke event:
- Swap in a MERV-13 filter. Available online or at any hardware store. No contractor is needed.
- Run your system in constant fan mode (sometimes labeled "fan on") or recirculation mode if your thermostat offers it. This keeps air moving through the filter without drawing smoky air in from outside.
- During severe events, ask your contractor about temporarily closing your fresh air intake or HRV. It is a simple step that makes a real difference when outdoor air quality is at its worst.
The EPA found that combining a MERV-13 filter with continuous fan circulation reduces indoor PM2.5 by about 50%. That is a meaningful difference for a child with asthma or for an older adult with a heart condition.
Here is the bonus: a heat pump does not just filter better — a high-efficiency heat pump can be up to 40% more efficient than a standard AC unit. With summer electricity bills projected to average $778 this year (up 8.5% from last summer, according to NEADA), running a more efficient system is not just good for your air. It is good for your wallet, too.
Your windows are the other half of the clean air protocol
Think of it this way: your heat pump is the filter. Your windows are the seal. Both are needed for the best indoor air quality.
Even the best filtration system has a harder job when smoke seeps in through gaps around old, drafty windows. Older single- or double-pane windows with worn seals allow fine particles to infiltrate constantly, even when closed. Your filter ends up chasing air that keeps finding its way back in.
High-performance triple-pane windows create a much tighter envelope. Less infiltration means your heat pump and filter have less work to do, and your indoor air stays cleaner, longer. As a bonus, triple-pane windows also reduce heat gain in the summer, so your system runs at a lower capacity, and your bills go down even more.
The Wise Window Hub connects Minnesota homeowners with resources, research, and contractors who specialize in high-performance windows. When shopping, ask your contractor specifically for triple-pane windows or windows with a U-factor of 0.22 or less for the best energy efficiency.
Why a heat pump and a better filter change everything
You should not have to choose between staying cool and breathing clean air. A cold climate heat pump with a MERV-13 filter, paired with well-sealed windows, gives your home real protection against smoke, heat, and rising energy costs, all at once.
Families with children who have asthma, older adults, and people with heart or lung conditions are the households that stand to benefit most. And they are often the same households that have had the least access to efficient, modern equipment. Getting these upgrades into more Minnesota homes is more than an energy opportunity. It is an opportunity to improve health and well being.
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