A Fall Furnace Checkup Before the Cold Arrives

There is a certain day every fall in Calgary when the air has a different kind of chill. It is not the crispness of September, but something sharper that hints at what is ahead. On that day, or more likely that night, someone in the house will walk over to the thermostat and move the setting from "cool" to "heat". A few minutes later, a familiar smell drifts through the rooms: the dusty, slightly burnt scent of a furnace coming on for the first time in months. Most people just accept it as part of the season, but that smell is your furnace giving you a small reminder that it could use some attention before it settles in for a long winter.

That First-of-the-Season Smell

That recognizable odor comes from a summer's worth of dust settling on the internal parts of your furnace, mainly the heat exchanger. When the furnace fires up, this layer of dust burns off in a hurry. It is usually harmless and the smell fades within an hour or so. Still, it is a clear sign of how much fine debris gets drawn into your heating system over time. This dust does not just sit on the heat exchanger. It works its way into the blower motor, coats fan blades, and most of all, packs itself into the furnace filter. A clean furnace tends to be more efficient and more dependable, and dealing with that dust is the first step.

What a Homeowner Can Do

A yearly checkup by a licensed gasfitter is always a good idea, but there are a few simple maintenance tasks most homeowners can handle themselves to keep the system running well. Before you open any panels on your furnace, you must shut off the power to it. There will be a standard light switch, often mounted on the side of the furnace or on a nearby wall, that serves as a service switch. Turn that off. For good measure, I always trip the breaker for the furnace in the main electrical panel too. Safety comes first.

With the power off, you can focus on the most important job: the filter. This is a rectangular screen, usually one inch thick, that slides into a slot on the side of the furnace where the large metal duct for return air connects. A dirty filter is the most common cause of furnace trouble. It chokes the flow of air, forcing the blower motor to work harder, which can lead to overheating and shutdowns. Slide the old filter out and have a look. If it is grey and clogged with dust and hair, it is long past due. Replace it with a new filter of the exact same size, making sure the arrows on the filter's frame point toward the furnace, in the direction of the airflow. Checking this filter monthly during the heating season is a good habit.

While you are there, you can use a vacuum with a brush attachment to gently clean out any dust bunnies from the bottom of the furnace cabinet and the area around the blower. Do not touch any wiring or the gas lines. Just a simple cleanup of the accessible compartment makes a difference.

The Importance of Airflow

A furnace works by heating air and moving it through the house. Anything that restricts that flow of air makes the whole system less effective. It is a bit like trying to breathe through a straw. A clogged filter is the main bottleneck, but there are others. Take a walk through your home and make sure none of the supply or return air vents are blocked by furniture, rugs, or piles of storage. Every vent has a purpose. The large return air grilles pull air back to the furnace to be heated, and the smaller supply registers send the warm air into each room. The system needs to breathe freely to do its job. Good airflow not only helps the furnace run efficiently, it also helps it heat the house more evenly.

I remember an inspection in a perfectly nice home where the owners complained about one bedroom being freezing all winter. The furnace was fine, the ductwork was all connected. After a few minutes of looking, I found the problem: they had pushed a large, heavy dresser right up against the only heat register in the room. The hot air was simply blowing into the back of a piece of furniture. Sometimes the simplest things are the easiest to overlook.

When to Call a Licensed Technician

There are parts of a furnace that should only be serviced by a professional. This is not a place for ambitious DIY efforts, as it involves natural gas and carbon monoxide safety. When you book a professional cleaning and service, a technician will perform tasks that go beyond a filter change. They will clean the flame sensor, a small metal rod that confirms the gas has ignited. If this sensor gets dirty, it can fail to detect the flame and will shut the furnace down as a safety precaution. They will also clean the burners themselves to support a clean, efficient flame.

Most importantly, a technician will inspect the heat exchanger. This is the metal chamber that separates the burning gas from the air that blows through your home. A crack in the heat exchanger is very dangerous, as it can allow carbon monoxide to mix with your household air. An inspector has the tools and training to spot these fine cracks, which are often invisible to the naked eye. This check alone is worth the price of a professional service call. They will also check gas pressures, test safety switches, and inspect the venting system. It is a thorough checkup that lets you run the furnace through the cold months with more confidence.

Getting the furnace ready is just one part of fall prep; you also need to think about your garage door in the cold when the temperature drops. A little bit of planning in autumn saves you from dealing with problems on a frigid January morning. A warm house and a working garage door make winter a lot easier to live with.