Few things are more stressful during an Orillia winter than turning on the furnace… and feeling cold air coming through your vents. It happens more often than you’d think, especially during the sudden temperature drops Orillia is known for.
Here are the most common causes we see:
1. The furnace overheated and shut down
When airflow is restricted—usually due to a dirty filter—the furnace can overheat and trigger a safety shutdown. The fan keeps running but the heat stops.
2. Frozen vent pipes
Orillia’s deep freezes often cause frost buildup in high-efficiency furnace vent pipes. When this happens, the furnace can’t ignite properly and may run without producing heat.
3. Ignition or flame sensor issues
Cold temperatures make ignition components work harder. If your furnace tries to light but the flame sensor doesn’t detect heat, it will shut down for safety.
4. Low gas pressure during extreme cold
During provincial cold snaps, natural gas pressure can drop slightly. Furnaces with borderline performance may fail to ignite consistently.
What to Do
If your furnace is blowing cold air, shut it off, check the filter, and make sure your exterior vent pipes aren’t buried in snow or ice.
If everything looks normal, call
Mr. Heat Furnace Orillia
—we can usually diagnose the issue within minutes.
