Penelope Graham
09 Oct 20269 min read
With autumn now in full swing in the Greater Toronto Area, you may find yourself cranking up the thermostat more frequently, especially in the mornings and evenings when temperatures dip to single digits.
When bringing your furnace back into regular service for the season, it’s smart to do a few quick maintenance checks. Here’s a handy checklist of furnace-care tasks that homeowners can do themselves to keep everything running smoothly.
Clean the area around your furnace
Change your furnace filter
Turn on your furnace humidifier
Test and replace your carbon monoxide alarms
Note: When it comes to furnace maintenance or repair, leave anything to do with gas, combustion, or electricity to a TSSA-certified HVAC Pro. Check out our blogs on what comes with a professional furnace tune up, and questions to ask when hiring an HVAC contractor.
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Given furnaces are usually found in basements, it can be easy for clutter and storage to creep into the space around the unit. Not only is this a safety issue – having anything like cardboard boxes or clothing nearby poses a fire hazard – but objects can block your furnace’s airflow, making it work harder to efficiently distribute heat around your home. This can both drive up heating bills, and make the unit wear out faster. Chemicals or paint should also not be stored nearby, as being close to a heat source can activate and release fumes. Because of this, it’s a good rule of thumb to keep at least three feet of clearance around your furnace.
The same goes for your furnace’s exterior piping outside your home, checking that the area around any intake and exhaust vents is clear.
“Check the exterior of the house, making sure that there's no bins or garbage, especially if the furnace is double piped (when one pipe pulls in outdoor air to be heated, and the other expels exhaust),” says Ali Shaikh from Blue Leaf Home Services. “Make sure all the leaves and everything are thoroughly removed.”
Check each interior room too, making sure all furnace vents and returns are clear; keep an eye out for furniture that may have been pushed over the vents, built-up dust on the grilles, and that other objects, like rugs or toys, aren’t covering the registers.
Changing your furnace filter should be a regular task – between every one to three months, depending on its type and thickness – but it’s especially important at the start of the heating season to clear any dust that’s settled over the summer. When you turn your furnace on for the first time, air will blow any build up into the existing filter, so you want to ensure it’s not already clogged.
Having a clogged filter reduces the efficiency of your furnace, and places strain on the overall system by making the blower motor work harder – and wear out your unit faster. Routinely changing your filters reduces this strain, and can also help lower your energy bills.
Here’s a step-by-step guide on how to change a furnace filter:
1- Turn off your furnace. Your unit must be powered off before it’s safe to open the filter cabinet. Reaching in while the blower fan is still running can cause injury, and taking the filter out while the machine is on can pull dust and debris directly into the system.
You can turn your furnace off either at the thermostat or the power switch; this is usually mounted on the outside of the furnace cabinet, or on a nearby wall. If you can’t find it or are unsure, you can also turn your furnace off by flipping its circuit breaker to the off position (likely labelled HVAC or FURNACE).
2 - Find the filter cabinet. The filter is typically located in either a slot or cabinet where the return air duct meets the furnace, though sometimes it can also be behind a return grille within the wall or ceiling close to the unit.
3 - Remove the old filter. Simply pull the previous filter out and place it in a trash bag.
4 - Insert the new filter. First, confirm which direction the airflow arrow points on the filter. Slide the new filter into the slot, ensuring this arrow points towards the furnace or blower.
5 - Secure the cabinet or grille cover, then turn the power back on.
Furnace filters vary in quality and size. Standard filters are typically one inch thick and require monthly changing, though thicker filters can be replaced less frequently. Reusable filters, which are washed monthly rather than replaced, are also an option for those looking to create less waste or save money over time.
A filter’s quality is based on the amount and size of debris it lets through, which is measured by its MERV (Minimum Efficiency Reporting Value) rating. The higher the rating, the better the filtration. Standard residential furnace filters will range between a MERV rating of eight to 13, with between 11 to 13 considered ideal for those with allergy and asthma.
However, too high a MERV rating (such as a full HEPA filter) on a residential furnace can actually restrict its airflow and slow it down; always check the manufacturer’s recommendation for maximum MERV rating when picking a filter. This can be found in your owner’s manual, the manufacturer’s website, and sometimes on a label inside the furnace blower cabinet.
While every 30 to 90 days is the standard replacement schedule for most filters, you may want to change yours more frequently if you live in a home with multiple pets, or have household members with breathing sensitivities. Homes that are undergoing renovation, or are located in dry, dusty regions, can also benefit from more frequent filter changes.
Not all furnaces come with a built-in humidifier, but they’re quite popular in the GTA due to our cold winters and the dryness from constantly running heat indoors. Furnace humidifiers can help with overall comfort, preventing dry skin and throats, reducing static electricity, and making the air feel warmer with humidity between 30 to 50%.
Also called whole-house humidifiers, these are add-on appliances that are built directly into the furnace’s ductwork. They are plumbed to your home’s water line, and controlled by a separate unit called a humidistat.
The most common types include bypass humidifiers, which use the furnace blower to push air through a water pad, and steam humidifiers, which have a separate chamber to boil water into steam, which is then mixed with the airflow.
Furnace humidifiers should be dormant in the summer. It’s not advisable to run them when it’s already warm and humid, because they add excessive water vapor to the air, leading to a sticky feeling in the home, and raising the risk of mould growth. That means that, like your furnace, the unit is turned on for the first time in the fall, and must be in good shape to keep up with the heavy heating season.
To get your furnace humidifier up and running again:
1 - Replace the water panel or filter: Your humidifier has a filter that needs replacement on an annual basis. To do this, turn off the power source to the unit, and remove its front cover. Slide out the old filter and insert the new one with the marked side (this will vary between models) facing up.
“Homeowners often say, ‘Oh, I didn’t know I had a filter,’ or, ‘I forgot about that filter’.”
RJ Donaldson, Canaduct
Failing to replace the humidifier filter – or not being aware that it exists at all – is a common issue that leads to black mould growth, says RH Donaldson from Canaduct.
“Homeowners often say, ‘Oh, I didn’t know I had a filter,’ or, ‘I forgot about that filter.’” he says. “If you have a humidifier make sure you check the filter and change it annually.”
2 - Turn on your water supply valve: This is the small water line (usually made of plastic or copper) connected to the humidifier. Turn the valve until the handle sits parallel to the pipe, with water flowing into the system.
3 - Turn the damper to winter mode: A damper is a valve located within your furnace or humidifier ductwork that directs the flow of air to certain rooms within your home. Turning it to “winter mode” will open the airflow passage so warm air connects with the water panel to pick up moisture before flowing out to the remainder of the house.
4 - Adjust the humidistat: Now that your humidifier is back in service, adjust your wall unit controls to between 30 to 45% humidity. Keep an eye on the inside of your windows; if they start to fog or form condensation, it’s a sign your humidity percentage is too high.
It’s always important to have functioning CO alarms on every level of your home, and to test them monthly, but give them some extra attention as your furnace kicks into high gear.
“Make sure CO detectors, smoke alarms, all that stuff, is up to date, especially in the winter time,” says Shaikh.
He adds that units benefit from a regular vacuuming to make sure they don’t have dust and dirt build up – this can be done with any handheld vacuum or hose with a soft brush attachment. Replace them altogether if they’re over 10 years old, discolored, or are failing their monthly testing.
Testing your CO alarm is simple; press and hold the TEST button, which should cause a series of beeps, and there may also be an indicator light. Release the button and make sure the alarm stops. If you hear a single chirp instead of a full alarm sequence, that’s a sign the battery is low and needs to be changed out. If the unit doesn’t make any sound at all, even after a battery change, it should be replaced.
In addition to monthly checks, it’s also smart to re-test your CO alarm any time the battery has been changed, the home has experienced a power outage, or when you’ve returned after the home has been dormant for a period of time, such as a vacation.
“The fireplace is one of the most dangerous appliances in the house because it’s the least maintained.”
Ali Shaikh, Blue Leaf Home Services
Shaikh adds that anyone with a working fireplace in their home has additional carbon monoxide considerations, even if they don’t use the fireplace on a regular basis. This is because if the homeowner does decide to turn it on – say, in the case of a power outage – it can become a CO hazard due to a build up of contaminants. That’s why it’s important to still do an annual chimney sweep and inspection.
“The fireplace is one of the most dangerous appliances in the house because it’s the least maintained,” he says.
“You hear of people having their carbon monoxide detectors going off, and it’s because they're firing up a fireplace that they haven't run in five years. Make sure the fireplace is in good working condition and if it’s not, make sure it’s disconnected or isolated.”
No one wants to deal with a furnace emergency mid-winter. Taking the time in the autumn to ensure everything is in good working order, knowing how old your unit is, and staying on top of filter replacement, help you be an informed homeowner – and be prepared if your unit ever does need a repair or replacement.
Penelope Graham
Penelope is the Editor at Quartermaster. She has years of experience writing about Toronto’s unique housing and mortgage market, and is always chatting with Pros about their top tips for homeowners.
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