Before Ontario’s winter weather settles in, check your heating system, test your alarms, and arrange professional maintenance. Preparing early gives you an opportunity to address problems before you depend on your furnace every day.

Start with these homeowner checks — and remember that a successful test run does not replace a professional safety inspection.

1. Book your annual furnace inspection

Your furnace may turn on and produce warm air while still having issues you cannot see.

TSSA recommends an annual inspection of fuel-burning appliances by a certified fuels technician. For gas furnace work in Ontario, choose a TSSA-registered contractor employing appropriately certified technicians.

Leave inspections of internal components, gas connections, and combustion systems to the professionals. Never bypass a safety control or attempt a gas repair yourself.

2. Check your furnace filter

Before starting your furnace, inspect the filter according to your equipment manual. A dirty filter can restrict airflow and contribute to operating problems.

If you need to replace it, use the size and type specified for your system. Follow the manufacturer’s instructions to safely turn off the equipment, access the filter, and install it correctly.

Filter replacement schedules vary by equipment, filter type, and household conditions, so follow your system’s guidance rather than assuming one schedule works for every home.

3. Test smoke and carbon monoxide alarms

Include your alarms in your fall maintenance routine. Test them monthly, follow the manufacturer’s battery instructions and check whether the units have reached their replacement date.

Carbon monoxide, or CO, cannot be seen or smelled. Working CO alarms are essential protection, alongside regular maintenance of fuel-burning equipment.

Ontario homeowners: check your alarm placement. As of January 1, 2026, houses with a fuel-burning appliance, fireplace, or attached garage require working CO alarms on every storey and adjacent to each sleeping area, installed according to manufacturer instructions. Condos and apartments have requirements based on the unit and building configuration; consult your local fire department if you are unsure what applies.

4. Keep airflow and the furnace area clear

Check that furniture, rugs, and curtains are not covering supply registers or return-air grilles.

Keep the area around your furnace free of boxes, laundry, and other stored materials. Follow the equipment manufacturer’s clearance requirements and keep flammable products away from heating equipment.

Your utility room should provide safe access for servicing—not become overflow storage.

5. Look at outdoor intake and exhaust vents

From a safe, ground-level position, check accessible outdoor furnace vents for leaves or other obstructions. Continue checking throughout winter as snow and ice accumulate.

Blocked venting can create a carbon monoxide hazard. Do not insert tools into pipes, dismantle venting, or climb to inspect a chimney. Ask a qualified professional to handle damage, inaccessible blockages, or anything you cannot safely assess.

6. Test your heat before you need it

Once the basic checks are complete—and there are no suspected safety issues—follow your furnace manual’s startup instructions. Use the thermostat’s heating setting and raise the temperature slightly above the current room temperature.

Check whether the system starts and warm air reaches theregisters. Stay home while observing its operation.

If the furnace fails to start, repeatedly shuts down, makes unusual noises, or produces a persistent burning smell, stop using it and contact a qualified contractor. Avoid repeated resets.

Warm air confirms that your system is heating. It does not confirm that every component is safe.

Know when to leave immediately

If a CO alarm sounds: Get everyone outside into fresh air immediately and call 911 from outside. Do not search for the source. Return only when emergency responders say it is safe.

If you smell gas or suspect a leak: Leave immediately. Do not operate switches, appliances, or phones inside, and do not attempt to locate or repair the leak. From a safe location, call your gas utility’s emergency line or 911.

These situations require emergency help, rather than an online service request.

Make winter preparation part of your fall routine

A filter check, working alarms, clear vents and an annual professional inspection are practical steps toward preparing your home for heating season.

If a professional assessment indicates that your furnace needs replacing, Vista Services can help you explore home comfort equipment options through our local contractor partners.

Thinking about a furnace upgrade? Contact Vista today and explore your options.

This checklist provides general homeowner information. Always follow your equipment manufacturer’s instructions and use a qualified professional for inspections, diagnosis, and repairs.

‍