Why You Should Check Your Furnace Intake & Exhaust Pipes Now That the Snow Is Falling
When the snow starts piling up in the North Country, most homeowners think about shoveling driveways, clearing sidewalks, and brushing off vehicles. But there’s one area many people don’t think about, and it could mean the difference between a warm home and a dangerous emergency:
👉 Your furnace’s intake and exhaust pipes.
These pipes are often located on the exterior of your home, close to ground level. During heavy snow, drifting, or extreme cold, they can easily become blocked by snow buildup or sealed with ice. And when that happens, your heating system, and your family’s safety is at risk.
Why These Pipes Matter
High-efficiency furnaces (90%+ AFUE units) use PVC pipes to bring in fresh air (intake) and expel combustion gases (exhaust). When these pipes are blocked, your furnace can’t breathe properly.
A blockage can cause:
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Furnace shutdowns
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Reduced heating performance
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Dangerous carbon monoxide buildup
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Frozen pipes in the home due to loss of heat
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Costly emergency repair calls
Modern furnaces have safety shutoffs that detect the problem and turn the system off, but that still leaves you without heat when you need it most.
How Snow and Ice Block Your Furnace Pipes
North Dakota winters create the perfect storm for pipe blockage:
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Heavy snowfall that drifts against the house
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Blowing winds that pile snow around vent areas
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Ice buildup from melting exhaust vapor
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Freezing rain or slush storms that freeze solid overnight
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Snowfall off roofs that drops directly onto vent openings
Even a partial blockage can cause issues, especially during long stretches of subzero weather.
Warning Signs Your Intake or Exhaust Pipe May Be Blocked
Watch for these symptoms:
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Furnace turns on and then quickly shuts off
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Error codes on your thermostat or furnace panel
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Unusual sounds coming from the furnace
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Reduced airflow from your vents
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Condensation or frost around the vent area
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Strong smell of exhaust outdoors near the vent
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Home not warming up despite furnace running
If you notice these signs, check your exterior pipes immediately.
How to Safely Check (and Clear) Your Furnace Pipes
Here’s what homeowners can do:
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Locate the intake and exhaust pipes
Usually two white PVC pipes exiting through the side of the home. -
Clear away snow and drifts
Shovel a wide berth around the pipes, at least 3 feet of open space. -
Check for ice buildup at the opening
Lightly tap or brush away frost or ice. DO NOT use sharp objects. -
Make sure the pipes are unobstructed
Look inside the openings to confirm nothing is lodged or frozen. -
Ensure proper height clearance
If your pipes sit low, snowfalls over 6-8 inches can easily block them. -
Monitor regularly during storms
Keep an eye out after every heavy snowfall or wind event.
When to Call a Professional
If the furnace still doesn’t start after clearing the pipes, or if you find:
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Thick ice you can’t remove
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Repeated shutdowns
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Strong exhaust smell
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Visible damage to the PVC pipes
 it’s time to call a licensed HVAC technician. Blocked vents can cause hidden problems that need expert attention.
A Simple Winter Habit That Can Prevent Emergencies
In North Dakota’s harsh winters, it’s smart to build this into your routine:
After every snowfall or windstorm, check your furnace intake and exhaust pipes.
It takes less than a minute, and it can prevent:
❄️ Loss of heat
❄️ Frozen plumbing
❄️ Carbon monoxide risks
❄️ Expensive repair calls
Stay Safe and Stay Warm
Your furnace works hard all winter long, make sure it can do its job safely. Keeping your intake and exhaust pipes clear is one of the easiest (and most important) steps to ensuring reliable heat through the coldest months.
If you’d like help with a furnace inspection, a winter readiness check, or a quick vent clearing, our team is here to help.
Check out this article from Dept of Energy on combustion appliance safety. https://www1.eere.energy.gov/buildings/publications/pdfs/building_america/26464.pdfÂ
