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.

Orillia winters can be unpredictable—one day mild, the next extremely cold. The best way to avoid emergency furnace calls is to prepare your HVAC system before the season hits its peak. Here’s a homeowner-friendly checklist used by the technicians at Mr. Heat Furnace Orillia : 1. Replace your furnace filter before the temperature drops A fresh filter improves airflow, reduces energy bills, and helps prevent overheating shutdowns. 2. Schedule a fall furnace tune-up Tune-ups catch early signs of ignition issues, blower problems, cracked hoses, and worn components—all of which commonly fail during heavy winter use. 3. Clear snow and ice from exterior vents High-efficiency furnace vent pipes can freeze easily. Keeping them clear ensures your system runs safely. 4. Test your thermostat settings Make sure your thermostat responds properly and is placed away from cold drafts. 5. Seal windows and doors Even the best furnace can’t compensate for major heat loss around windows and doorframes. Weatherstripping and caulking can drastically reduce heating costs. 6. Listen for unusual furnace sounds Banging, rattling, or grinding noises are early indicators of a mechanical failure. Why It Matters Preventative work saves Orillia homeowners hundreds of dollars in avoided breakdowns and keeps your home consistently warm through the coldest storms. If you want peace of mind this winter, Mr. Heat Furnace Orillia can perform a complete winter-readiness check to make sure your system is prepared for whatever the season brings. Contact us today for fast HVAC services !