Removing snow from furnace vents can be a life-saving task.

From a home inspector’s point of view, keeping furnace venting pipes clear of snow in winter is a big safety and performance issue, not just a maintenance tip.

Here’s how inspectors typically explain it to homeowners:

1. Blocked vents can force exhaust gases back into the home

High-efficiency furnaces vent combustion gases (including carbon monoxide) through PVC pipes that usually exit the side of the house. If snow drifts, ice, or packed snow block that pipe, the furnace can’t exhaust properly.

Best-case scenario: the furnace shuts down as a safety precaution. Worst-case scenario: exhaust gases spill back into the home, creating a serious carbon monoxide hazard.

That’s a red-flag condition for any inspector.

2. Snow blockage can cause furnace shutdowns (or no heat at all)

Modern furnaces are designed to protect themselves. If the vent or intake is blocked, pressure switches may trip and shut the system down.

From an inspector’s view, this often shows up as:

• Homeowners reporting “random” heat loss

• Service calls during heavy snowstorms

• Emergency no-heat situations in extreme cold

All of that is avoidable with a clear vent.

3. Ice buildup is just as dangerous as snow

Even if snow doesn’t fully block the pipe, partial obstruction can cause exhaust moisture to freeze inside or at the termination point.

Inspectors watch for:

• Ice caps on vent ends

• Sagging vent pipes holding condensate

• Improper slope that allows freezing

  

Once ice forms, airflow drops fast—and the furnace can’t breathe.

4. Improper vent height is a common defect

During inspections, vents are often found:

• Too close to grade

• Located where snow drifts accumulate

• Installed without regard to roof runoff or plowed snow piles

Most manufacturers require vent terminations to be well above expected snow levels. If they’re not, inspectors will call it out as a safety concern.

5. Clear vents protect both safety and equipment lifespan

Restricted venting forces the furnace to operate under stress, which can lead to:

• Short cycling

• Heat exchanger damage

• Premature system failure

From an inspector’s standpoint, that’s not just unsafe—it’s expensive for the homeowner.

Inspector’s bottom line

Keeping furnace vent pipes clear of snow is about:

• Preventing carbon monoxide exposure

• Ensuring reliable heat in winter

• Avoiding unnecessary furnace damage

• Maintaining manufacturer-required clearances

Inspectors often recommend homeowners visually check vent pipes after heavy snowfall—especially during storms with drifting snow or extreme cold.