Common Furnace Problems and When to Call a Pro
Alberta winters are unforgiving. When your furnace starts acting up in January, you need answers fast. Here are the most common furnace problems homeowners in Airdrie, Calgary, Cochrane, and surrounding communities face — and what to do about each one.
Dirty or Clogged Air Filter
A dirty filter is the single most common cause of furnace problems. When airflow is restricted, your furnace overheats, short-cycles, and works harder than it should. Replace your filter every one to three months during heating season — more often if you have pets or a dusty home. A clean filter is the cheapest furnace maintenance you can do.
Furnace Not Producing Enough Heat
If your furnace is running but your home is not reaching the set temperature, the cause could be a dirty filter, a failing heat exchanger, a malfunctioning thermostat, or blocked vents. Check your filter and vents first. If those are clear and the problem persists, call a licensed technician. A heat exchanger issue is not something to ignore — a cracked exchanger can allow carbon monoxide to enter your living space.
Short Cycling
Short cycling means your furnace turns on, runs briefly, then shuts off before the home reaches temperature — and repeats the cycle over and over. This is hard on your equipment and drives up your energy bills. Common causes include an overheating furnace (often a dirty filter), a faulty flame sensor, or an oversized unit. A technician can diagnose the root cause and prevent long-term damage.
Unusual Noises
Banging, rattling, squealing, or rumbling sounds from your furnace are never normal. Banging on startup can indicate delayed ignition. Rattling may point to loose panels or ductwork. Squealing often means a worn blower belt or motor bearing. Any persistent noise warrants a professional inspection before it becomes a more expensive repair.
Yellow or Flickering Pilot Light
A healthy pilot light burns blue. A yellow or orange flame is a warning sign that your furnace may be producing carbon monoxide — a colourless, odourless gas that is extremely dangerous. If you see a yellow flame, turn off your furnace, ventilate your home, and call a technician immediately. Do not attempt to fix this yourself.
Burning or Sulphur Smell
A brief burning smell when you first turn on your furnace for the season is normal — it is just dust burning off. A persistent burning smell, or any smell of sulphur or rotten eggs, is not. Sulphur odour can indicate a gas leak. Leave your home immediately and call your gas utility and a licensed technician.
When to Call Monty's
Some furnace issues — like replacing a filter or adjusting a thermostat — are straightforward. But anything involving gas lines, heat exchangers, electrical components, or carbon monoxide risk should always be handled by a licensed technician. Monty's Plumbing & Heating has been servicing furnaces across Airdrie, Calgary, Cochrane, Crossfield, Carstairs, and Rocky View County for over 35 years. We offer 24/7 emergency heating service so you are never left in the cold.
Annual furnace tune-ups before winter are the best way to catch small problems before they become expensive failures. Book your fall inspection today.