Top 7 Reasons Your Furnace Isn’t Heating Properly in Calgary

Justin Meagher • October 30, 2025

Is your Calgary furnace blowing cold air or just not running like it used to? Learn the seven most common causes and how to fix them before winter hits.

When Calgary’s temperatures plunge below zero, a malfunctioning furnace can go from inconvenient to urgent overnight. If your system isn’t heating your home like it used to, it’s often due to a few common (and fixable) issues.

 

1. Dirty or Clogged Air Filter

A clogged filter restricts airflow, forcing your furnace to work harder and deliver less heat. Calgary’s dry, dusty winters make this one of the top culprits—check and replace filters every one to three months.

 

2. Thermostat Settings or Malfunction

Sometimes the issue isn’t the furnace—it’s the thermostat. Dead batteries, old wiring, or incorrect settings can all cause poor performance.

 

3. Blocked or Leaky Ductwork

Leaky ducts mean heat escapes before reaching your rooms. A quick inspection and sealing by a technician can improve efficiency dramatically.

 

4. Pilot Light or Ignition Problems

Older gas furnaces rely on a pilot light, while modern models use electronic ignition. If the flame won’t stay lit, call a professional—gas handling is best left to experts.

 

5. Blower Motor Issues

A weak or failing blower can’t push enough air through your ducts. You might hear whirring or grinding noises before complete failure.

 

6. Dirty Burners or Sensors

Dust and soot buildup prevent efficient combustion, especially after long periods without maintenance. Annual cleaning prevents this.

 

7. System Age

If your furnace is more than 15 years old, declining heat output might simply mean it’s time to replace it with a high-efficiency model.

 

Don’t wait for the next cold snap—schedule a furnace inspection with Lendrix HVAC Services today. We keep Calgary homes warm, safe, and efficient.

 

Written by the team at Lendrix HVAC Services Inc., proudly serving Calgary, Okotoks, Airdrie, Cochrane, Chestermere, and High River, Alberta.


LET'S TALK

AC Over 10 Years Old? - Why You Should Replace Today

By Justin Meagher • August 11, 2019
As you inspect the state of your old Air Conditioner, you’re probably wondering when is the ideal time to replace it. Here’s a few things you should consider while you’re weighing your options:

Buying A New Home? Have The HVAC System Inspected By A Licensed Tech

By Justin Meagher • August 5, 2019
Buying a new home requires a substantial sum of money upfront and will most certainly require additional financial investments throughout the years. To limit the number of surprises down the line, it’s important to know all the facts before you fully commit to buying a home. A proper HVAC inspection is essential to determine if the home is a sound investment.

Benefits Of A High Efficiency AC

By Justin Meagher • July 28, 2019
At the height of summer, temperatures across Canadian cities can soar. Unfortunately, some homeowners will learn that their AC system can’t keep up with the demand and will have to call for air conditioner service. Instead of wasting money on constant repairs for an old system—upgrade to a new high efficiency air conditioner and enjoy the benefits of increased efficiency, comfort and reliability.
Show More