You wake up after a heavy snowstorm in Saskatoon, turn up the thermostat, and wait for heat. Nothing happens. It’s a rough way to start a freezing morning. A furnace vent blocked by snow or ice could be the cause. It can stop your furnace from heating and may create a safety risk.

Before you assume something major has failed, check for loose snow around an outdoor vent you can reach safely. Don’t try to break off thick ice or keep resetting a furnace that shuts down. If the heat still won’t come on, these warning signs can help you decide when to call for furnace repair in Saskatoon.

What Should You Do if Snow Is Blocking Your Furnace Vent?

If your furnace stops heating after a snowstorm, check the outdoor vent for snow or ice. But if your carbon monoxide (CO) alarm sounds or you suspect CO exposure, leave the house and call 911 from outside. Don’t go back in until emergency services say it’s safe.

If there’s no sign of an emergency, here’s what you can do:

  • Clear loose snow: Remove snow from around the vent if you can reach it safely. Keep tools out of the pipe.
  • Don’t force off thick ice: Chipping at ice or pouring hot water on the vent can damage it. Leave this to a technician.
  • Check if the heat comes back: If the furnace still won’t start or keeps shutting off, call for service.

Don’t keep resetting the furnace to make it run. The snow may be gone, but the problem might not be.

How Does Snow Block a Furnace’s Intake or Exhaust Vent?

Your gas furnace needs air to burn fuel. It also needs a clear way to send exhaust gases outside. When snow piles up around either opening, the furnace may stop working.

What Is the Difference Between an Intake and an Exhaust Vent?

The air intake brings in air for combustion, while the exhaust vent carries combustion gases out of the house.

On many high-efficiency furnaces, these are plastic pipes that come through an outside wall. Some homes have a different setup, including roof vents. If you’re not sure which pipes belong to your furnace, don’t guess.

What Happens When Snow Blocks the Vent?

If snow blocks the intake, the furnace may not get enough air to burn fuel. If it blocks the exhaust, combustion gases can’t leave as they should.

Some furnaces will shut down when they detect a venting problem. You might hear yours try to start, then stop a few moments later.

That shutdown doesn’t mean everything is safe. A blocked exhaust can still pose a carbon monoxide risk, so don’t try to force the furnace to run.

 

What Are the Warning Signs of a Furnace Vent Blocked by Snow?

Your furnace was working fine yesterday, but now it won’t heat the house. If Saskatoon has had heavy snow or strong winds, it’s worth checking the outdoor vents. Snow or ice may be blocking one of them.

Here are a few signs to watch for.

The Furnace Won’t Start or Keeps Shutting Off

You turn up the thermostat and hear the furnace start, but it shuts off before the house gets warm. It might run for a few minutes, stop, and then try again.

This is called short cycling. A blocked intake or exhaust can cause it. Other furnace faults can do the same, so don’t assume snow is the only possible cause.

Your Furnace Runs, but the House Is Not Getting Warm

You can hear the furnace fan running, but the air coming through the vents isn’t warm. Meanwhile, the house keeps getting colder.

A blocked outdoor vent could be causing the trouble, though other furnace problems can also leave you without heat.

Snow or Ice Covers the Outdoor Vent Pipes

Sometimes, the problem is right outside your house. Snow may have drifted against the wall and covered the furnace pipes.

Look for:

  • Snow covering the pipe opening
  • Thick frost or ice around the vent
  • Slush that has frozen near the opening
  • Snow piled against the pipes after shoveling

Only check vents you can reach safely. If thick ice covers the opening or you can’t reach the pipes, leave them alone and call a technician.

The Furnace Displays an Error Code

You might notice a blinking light or an error code on the furnace. Some models show a pressure-switch fault when the system has trouble moving air or exhaust gases.

That doesn’t always mean snow is blocking the vent. Make a note of the code if you can see it without opening the furnace. It can help your technician narrow down the problem.

Why Is a Blocked Furnace Exhaust Vent Dangerous?

When snow blocks the exhaust pipe, gases from the furnace may not escape as they should. One concern is carbon monoxide (CO), which can build up indoors and put your family at risk.

You can’t see or smell carbon monoxide. It can cause headaches, dizziness, nausea, and confusion. High exposure can be deadly.

If your CO alarm sounds, don’t wait to see whether the furnace shuts off. Health Canada advises you to get everyone outside and call 911. Stay out until emergency services say it’s safe to return.

What if you smell rotten eggs? That could mean a natural gas leak, which is a different danger. Leave the area, avoid using switches or phones indoors, and call SaskEnergy at 1-888-700-0427 from a safe place.

What Can You Safely Check Before Calling for Furnace Repair?

If your furnace stops heating after heavy snow, check the outdoor intake and exhaust pipes for a blockage. You can do this without opening the furnace or touching its parts.

Check the Outdoor Vent From a Safe Place

Look for snow, frost, or ice covering the vent opening. Check from ground level, and don’t use a ladder or climb onto the roof. If you’re unsure which pipes belong to your furnace, leave them alone.

Clear Loose Snow Around the Opening

If you can reach the vent safely, clear loose snow from around the opening. Keep tools out of the pipe and avoid moving or damaging it.

If thick ice has formed, don’t try to chip it off or melt it with hot water. Leave that job to a heating technician.

Know When to Stop Checking

If the furnace still won’t start, keeps shutting off, or shows a fault code, call for service. A clear vent opening doesn’t rule out another problem.

Don’t keep resetting the furnace or bypass its safety controls to make it run.

When Should You Call a Furnace Technician in Saskatoon?

Call a heating technician if ice blocks the vent, the furnace keeps shutting down, or the heat doesn’t return after you clear loose snow.

Here’s what to do in each situation:

  • Your CO alarm sounds or you suspect CO poisoning: Leave the house and call 911 from outside. Wait for emergency services to confirm it’s safe to return.
  • You suspect a natural gas leak: Leave the area and call SaskEnergy at 1-888-700-0427 from a safe location.
  • Loose snow covers the outdoor vent: Clear it with care if you can reach it safely.
  • Thick ice blocks the vent: Don’t try to break it off. Call a heating technician.
  • The furnace won’t start after snow is cleared: Arrange furnace repair to find the cause.
  • The furnace keeps shutting off or displaying fault codes: Have it checked instead of resetting it again.
  • Ice keeps forming around the same vent: Have a technician check the venting system for the cause.

During a Saskatoon cold snap, don’t wait too long if your home is losing heat. Arrange help and consider staying somewhere warm until the furnace is fixed. Never use your oven or outdoor fuel-burning equipment to heat the house.

What Should You Tell the Technician?

When you call, share these details:

  • When the furnace stopped heating and whether it happened after snowfall
  • Whether the furnace tries to start, shuts off, or blows cold air
  • Any snow or ice you’ve noticed around the outdoor vent
  • Any fault codes and whether you’ve cleared loose snow

These details can help the technician narrow down the problem before checking the furnace.

What Will a Furnace Technician Check?

If you’ve cleared the snow but your furnace still won’t heat, a technician can check for blockages you can’t see. This may include ice inside the exhaust pipe, a blocked air intake, or problems with the vent connections.

On high-efficiency furnaces, frozen condensate drains can also cause heating problems. The technician may check the drain, pressure switch, and safety controls to find out why the furnace keeps shutting down.

Once the problem is fixed, they’ll check that the furnace runs safely. If the vents aren’t the cause, a broader HVAC system assessment may be needed.

How Can You Prevent Snow From Blocking Your Furnace Vent Again?

The City of Saskatoon advises homeowners to keep furnace intake and exhaust vents clear of snow and ice.

A few simple steps can help prevent another blockage:

  • Check after heavy snow: Look for snowdrifts or ice around outdoor vent openings.
  • Watch where you shovel: Keep snow piles away from furnace pipes.
  • Pay attention to recurring ice: If ice keeps forming around the same vent, have a technician check the cause.
  • Don’t change the vent setup: Avoid homemade covers or moving pipes yourself.
  • Keep up with maintenance: Have your furnace and venting system checked by a qualified technician.

Some frost around an exhaust vent can be normal in cold weather. Thick ice that blocks the opening is not something to ignore.

If you’re replacing an older furnace, ask the installer about proper vent placement to reduce the risk of snow buildup.

Further Reading: The Homeowner’s Guide to Reliable Furnace Installation in Saskatoon

Furnace Not Heating After Heavy Snow? Contact One Mechanical

If your furnace still won’t heat after you’ve cleared the snow, it needs a closer look. Ice inside the vent or another furnace fault may be keeping it from running.

One Mechanical provides furnace repair and 24/7 emergency heating services in Saskatoon. We can check what’s causing the problem and explain what repairs are needed.

For help with a furnace that won’t heat, contact our team or call 306-270-6356.