Homeowner Guide
Winter Furnace Maintenance Checklist
Winter in Ontario is no joke — and the coldest night of the year is the worst time for your furnace to quit. Run through this checklist every fall to keep your furnace safe, efficient, and reliable all winter long.
5 things you can check yourself
No special tools needed — just a few minutes and these simple checks.
Replace or clean the air filterEvery 1–3 months
Pull the filter out and replace it if it's dirty — or wash it if it's the reusable type. A dirty filter strains the blower motor and drives up your gas bill.
How to check: Hold the filter up to the light — if light doesn't pass through easily, it's time for a new one.
Check and clear the condensate drain line
On high-efficiency (condensing) furnaces, check the plastic drain tubes and hoses for blockages. Pouring a little white vinegar down the drain line helps clear algae and buildup.
How to check: While the furnace is running, watch for water dripping steadily from the drain line toward the floor drain or condensate pump.
Inspect the outdoor vent pipes
Go outside and check the openings of the plastic vent pipes (fresh-air intake and exhaust). Make sure they aren't blocked by leaves, nests, ice, or snow.
How to check: A quick visual check is enough — make sure nothing is obstructing airflow at the pipe openings.
Open and clean your air registers
Check all supply registers and return grilles in every room. Make sure they're open and not covered by rugs, furniture, or curtains.
How to check: Hold your hand in front of the registers — you should feel good, warm airflow.
Set the thermostat and replace the batteries
Switch the thermostat to Heat mode, set it a few degrees above room temperature, and replace the batteries if needed.
How to check: You should hear the thermostat click and the furnace fan kick in within 30–60 seconds.
What our professional furnace tune-up includes
Some jobs need a trained technician with the right tools. Here's everything we check during a professional winter tune-up:
Combustion & safety inspection
- Burners inspected and cleaned of dust and carbon for complete combustion
- Flame sensor cleaned so the furnace never shuts down unexpectedly
- Igniter tested for proper operation
- Heat exchanger carefully inspected for cracks, corrosion, or leaks — critical for preventing carbon monoxide (CO) leaks
- Gas connections and flue tested with gas and CO detectors
Venting & exhaust system
- Inducer motor tested — amperage, fan condition, and unusual noise
- Pressure switch and silicone hoses checked for blockages
- Vent pipes checked for blockages, proper slope, and sealed joints
Airflow & circulation
- Air filter inspected, replaced, or washed
- Blower motor and fan — amperage checked, blades cleaned, lubricated where applicable
- Indoor coil and air pathways checked for dirt and blockages
Electrical & controls
- Thermostat — operation, calibration, batteries, and communication with the control board
- Control board — wiring, relays, and terminals checked for burns or looseness
- Safety switches — door switch and high-limit switches tested
Final testing & calibration
- Gas pressure — inlet and manifold pressure measured and adjusted to the rating plate
- Temperature rise — supply/return differential checked against the furnace rating plate
- Full cycle test — a complete heating cycle verified from startup to thermostat shutoff
Safety first: If you smell gas, don't touch any electrical switches — leave the house and call your gas utility or 911. Never attempt gas or electrical repairs yourself.
Is your furnace ready for winter?
Book a professional tune-up today and avoid mid-winter surprises.