How to Clean a Furnace for Fall & Winter

In most Canadian homes, having an effective heating system like a furnace is necessary in the cold months of winter. However, for optimal performance and safety, it’s essential to properly clean your furnace. 

Learning how to clean a furnace can help you perform the basic maintenance to remove built-up dirt that causes poor air quality and inefficient heating. In this article, we’ll teach you the ABCs of furnace cleaning and when to call professionals for help.

Everything About Furnaces in Ontario 

There are different types of furnaces, including boilers, electric furnaces, heat pumps, and forced-air furnaces. In Ontario, forced-air furnaces have been homeowners’ go-to choice for their efficiency and affordability. 

A forced-air furnace burns natural gas or propane to generate heat and deliver warm air to your home. It consists of the following components that need regular cleaning: 

Parts of a Gas Furnace
Gas Valve	Receives gas from an external source and controls gas flow in the furnace
Burners	A tube with small holes that allows natural gas or propane to flow through for combustion
Ignition Switch or Pilot Light	Delivers a spark to the burner for combustion
Combustion Chamber	This is where the gas burns and generates heat
Heat Exchanger	Hollow metal tubing or thin sheets that transfer heat to passing air
Blower	Blows heated air throughout your home, gathers it back into the furnace, and exhausts it outdoors
Air Filter	Improves indoor air quality by filtering allergens from the air

Read more: The Ultimate Guide to Buying a New Furnace

Why Cleaning the Furnace in the Fall is Important 

Cleaning your furnace in the fall prepares it for the work it will do in winter. Not only does furnace maintenance optimize performance, it also brings the following benefits:  

• Energy Efficiency—Clean furnace components perform efficiently during the heating season, lowering energy usage, utility costs, and your carbon footprint. 

• Longevity—When you clean your furnace, you can spot the issues that can lead to a potential breakdown in the future. Addressing these issues early may help your furnace last 15 to 30 years!

• Safety—A clean furnace filter improves air quality, which may improve health conditions like asthma or allergies. Additionally, maintaining and inspecting your furnace reduces the risk of fires and gas leaks.

Read more: The Ultimate Seasonal HVAC Maintenance Guide for Homeowners

How Often Should You Clean Your Furnace? 

In general, most furnaces only require a thorough cleaning once a year. However, you may need to do it more frequently if you have pets or suffer from seasonal allergies. 

While gas furnace cleaning is seasonal, replacing air filters happens frequently. HVAC experts recommend homeowners change old filters with new ones every 90 days. A filter collects airborne dust, hair, and other small particles, so they don’t harm your furnace’s components.

Important Note: A furnace filter can be disposable or reusable. Ask your local HVAC technician about which kind you have at home. 

Hiring a Professional for a Furnace Inspection 

Aside from cleaning, homeowners should call professionals annually for a furnace inspection and tune-up to keep the unit running smoothly. HVAC contractors check furnaces’ heating components for any problems and implement solutions to prevent major issues. 

The best time to schedule an inspection is in the late summer or early fall before the temperature drops and you depend on your furnace to keep your home warm. Preventative maintenance is much better than a last-minute emergency call when your furnace isn’t working in the middle of winter.

The cost of gas furnace service in Ontario varies depending on your home and the services required. For a full quote, it’s best to ask your HVAC contractor directly. They will give you an accurate rate that accounts for the cost of service and labour.

Cleaning the Furnace in 10 Steps 

Below, we’ll go over the steps to clean a gas furnace. While you can perform some regular maintenance on your furnace to ensure it runs smoothly, this is a big job that may be better left to a professional who can ensure that your furnace will be in top condition for a warm and comfortable winter.

Step 1: Turn Off Power and Gas 

Cleaning the furnace starts with hitting the power button or unplugging the device from its electrical outlet. Gas flow needs to be shut off before any maintenance can be performed.

Step 2 : Clean Surface and Burners 

Wipe the furnace’s surface with a soft cloth or brush to remove any dirt or debris. Burners are accessed through the furnace access doors and can be cleaned using a vacuum cleaner with a brush attachment. 

Pro-tip: If you notice any soot in your burners, seek the advice of a professional.

Step 3: Remove and Clean Blower 

The blower must be carefully removed from the furnace, avoiding any wiring or other parts inside the unit before it can be cleaned. Vacuum the blower or use a small brush to remove any build-up.

Step 4: Clean Pilot Light or Hot Surface Ignitor 

Keeping this area clean is essential for proper furnace operation. Use a can of compressed air to blow the dust off the pilot light or hot surface igniter. 

Step 5: Clean Flame Sensor 

A blocked sensor prevents flame ignition and stops the furnace from working properly. Take the flame sensor from its bracket, then clean it with a soft cloth to remove any debris. 

Step 6: Inspect Belt Drive 

The belt drive helps the blower circulate air through the furnace chamber and into your home via ductwork. Inspect the belt drive for cracks or fraying, and replace it if necessary.

Step 7: Lubricate Mechanical Parts 

Applying oil to moving parts, like the blower, once a year will help keep them running smoothly and prevent wear and tear. Be careful to avoid over-lubricating, as this can cause problems.

Step 8: Replace Dirty Air Filter 

If you have pets or allergies, replace your air filter every three months, preferably more often. A dirty air filter reduces the efficiency of your furnace and can also be a fire hazard.

Step 9: Activate Burners 

Switch on your furnace or plug it back into an outlet to activate the burners. Watch for a yellow flame; this means the burners are dirty and require professional service. 

Pro-tip: Run the furnace burners for a few minutes once a month to prevent corrosion. 

Step 10: Adjust Dampers 

Adjust the dampers so they’re partially open when the furnace isn’t used. This will help circulate air and minimize moisture build-up, preventing mould and mildew from developing.

DIY vs Professional Furnace Cleaning 

DIY furnace cleaning may help you save money, but mistakes may end up costing more down the line. Lack of preparation or knowledge can worsen existing issues resulting in expensive emergency repairs. 

That’s not to say you can’t perform basic maintenance. Replacing furnace filters, wiping the unit’s surface, and keeping the ducts clear goes a long way. You can also keep an eye on the functionality of your furnace to call in professionals sooner rather than later.

Regular inspection and proper care from a professional are the best ways to keep your furnace system in optimal condition. A qualified HVAC professional will be able to diagnose and perform the required furnace maintenance, which will prevent costly repairs down the line.

Cost-Effective 

Professional services vary in price based on the HVAC components and the technician’s experience. Talk to your HVAC technician for a quote, and remember that a higher cost now is better than thousands of dollars in emergency repair costs after a DIY accident. 

Time Efficiency 

Licensed HVAC technicians have the skills, knowledge, and experience to service various furnaces. Their expertise and specialized equipment allow them to quickly and efficiently perform maintenance and deliver excellent results.

Peace of Mind 

DIY maintenance comes with the potential for damage and dangerous accidents, such as carbon monoxide leaks. Leave your furnace cleaning to the professionals to avoid the risk.

Don’t Wait for a Clean Furnace  

Cleaning a furnace alone can be a lot of work, and many people don’t have the tools or knowledge to do it themselves. While the cost of professional cleaning can be high, it’s nothing compared to the cost of repairs, replacements, or dangerous accidents. If you’re overwhelmed by the steps involved, don’t hesitate to call in professional help. 

Contact LG Home Comfort, Ontario’s favourite HVAC company, for same-day or next-day service from licensed professionals. We’ll ensure that your furnace is in good working condition, and ready for winter. 

Contact us for a free quote! Our experienced technicians are here for all your HVAC needs.