What to Do When Your Furnace Blows Cold Air: 5 Easy Checks

December 18, 2024 ,

Winter is here, and the last thing you want is a furnace blowing cold air. If your home feels more like a freezer than a cozy retreat, don’t panic—there are some simple steps you can take before calling for furnace repair. Here’s a quick checklist to troubleshoot the issue.

If these tips don’t resolve the problem, don’t hesitate to give LSM a call at 780-532-4418, including after hours.

1. Check the Furnace Power Switch

It might sound too simple to be true, but accidents happen! Many homes have a furnace power switch that looks like a regular light switch. It’s usually located in the mechanical room, often above the light switch and closer to the ceiling. Make sure it hasn’t been turned off accidentally.

2. Inspect Thermostat Batteries

If your thermostat screen is blank, the culprit could be dead batteries. Many thermostats rely on batteries to function. Replacing them might bring your system back to life and restore heat to your home.

3. Verify Thermostat Settings

Double-check that your thermostat is set to “Heat.” Sometimes, the setting can accidentally switch to “Off” or “Cool.” Adjust it back to “Heat” and ensure the temperature is set higher than the current room temperature.

4. Replace the Furnace Filter

A dirty or clogged furnace filter can restrict airflow, causing your system to overheat and shut down. Inspect your filter to see if it needs replacing.

  • Tip: Fibre-glass filters need to be changed monthly, while higher-end filters can last anywhere from 3 months to 1 year. For example, 5” wide MERV 11 or higher filters can last up to a full year. Regular replacement keeps your furnace running smoothly and improves air quality.

5. Check the Exhaust or Air Intakes

Head outside to inspect your furnace’s exhaust and air intake pipes. High-efficiency furnaces often have intake and exhaust vents on an exterior wall, while older systems may vent through the roof.

  • Look for:
    • Snow, ice, or debris blocking the vents
    • Overgrown bushes, lawn chairs, or other obstructions
    • Frost buildup on the vents

Clear any blockages to restore proper airflow and prevent your furnace from shutting down.

When to Call the Experts

If you’ve gone through these steps and your furnace is still blowing cold air, it’s time to call the professionals. LSM’s expert technicians are ready to diagnose and fix the issue quickly.

Contact us today at 780-532-4418 (any time).

Keep Your Home Warm This Winter

Regular furnace maintenance can prevent many common issues. Schedule an annual tune-up to keep your system efficient, safe, and ready for the cold months ahead.

For more home heating tips and expert advice, explore our blog or contact LSM today. Your comfort is our priority!