Quick answer
A real furnace tune-up in Ontario covers a heat exchanger inspection, burner and flame sensor cleaning, igniter resistance and flame-signal readings, manifold gas pressure set to the rating plate, temperature rise, blower and capacitor checks, a condensate trap flush, venting inspection, safety-control tests and a carbon monoxide reading. Expect 45–90 minutes and $120–$250 from a licensed GTA contractor.
What is included in a furnace tune-up in Ontario depends entirely on who you book, because the term has no legal definition — it covers everything from a genuine hour of testing and cleaning to a 15-minute filter swap that exists to sell you a furnace. The checklist below is what a TSSA-licensed technician should complete on a gas furnace, roughly in the order the work is done. Use it to compare offers, and to check the invoice afterwards.
The full furnace tune-up checklist
- Inspect the heat exchanger for cracks, corrosion and rust flaking — visually, with a camera where the cells are hidden, and by watching for flame disturbance when the blower starts. This is the one safety check that matters most.
- Remove and clean the burners; clean the flame sensor with fine abrasive and confirm a steady flame signal, measured in microamps, at the control board.
- Test the hot surface igniter and measure its resistance; a reading drifting out of range means it is on its way out before it fails.
- Check manifold gas pressure with a manometer and set it to the rating plate — about 3.5 inches of water column on most natural-gas furnaces — and confirm inlet pressure with the other gas appliances running.
- Measure temperature rise across the furnace and confirm it sits inside the range printed on the rating plate; too high means airflow is short.
- Check the blower wheel for dust loading, the motor amp draw against its label, and the run capacitor's microfarad reading.
- Flush the condensate trap and drain line on a high-efficiency model, and check the pump if there is one.
- Inspect venting: PVC slope and joints on a condensing furnace, connector condition and draft on a chimney-vented one, and the intake terminal for nests and debris.
- Test the safety controls: high-limit, pressure switch, rollout switches and the blower door switch.
- Measure carbon monoxide in the flue and in the air around the furnace.
- Check or replace the filter, test thermostat operation, and record the model, serial and any stored fault codes for the service history.
How long a furnace tune-up takes and what it costs
A tune-up that covers that list takes 45–90 minutes. Across the GTA, a standalone visit runs $120–$250. A maintenance plan bundles the fall furnace visit with a spring AC tune-up for $150–$350 a year, adds priority scheduling in a cold snap and repair discounts, and is usually the better buy if you intend to service the system every year — which manufacturers expect; see how often to service a furnace in Ontario.
What a $59 special leaves out
A tune-up priced far below cost is a lead-generation visit. The tells: no manometer or combustion analyzer comes out of the bag, the burners are not removed, the heat exchanger is declared cracked in under 10 minutes with no photo, and the visit ends with a replacement quote. Ask for the readings — gas pressure, temperature rise, flame signal, CO — on the invoice. A technician who took them will have them; one who did not will change the subject.
What a tune-up does not include
Cleaning, testing and adjustment are included; parts are not. If the igniter reads out of range or the capacitor is weak, replacing it is a separate line — a flame sensor at $150–$300, an igniter at $200–$450, a capacitor or pressure switch at $250–$500 — and a good technician shows you the reading before recommending it. Replacing a worn part on the tune-up visit is cheaper than the same part on a no-heat call in January.
Does a furnace tune-up matter?
- Safety — the heat exchanger and CO checks catch the failures that put households at risk, and the ones a homeowner cannot see.
- Warranty — most manufacturers require documented annual maintenance to keep the 10-year parts warranty valid; keep the invoices.
- Efficiency — clean burners and correct gas pressure keep a 95% furnace running at 95%.
- Reliability — igniters, capacitors and flame sensors show wear in their readings a season before they fail, so they get replaced on your schedule rather than at 2 a.m.
When to book a furnace tune-up
Early fall, before the first cold night sends every furnace in the region into its first cycle of the year. September bookings get flexible scheduling; late October and November are the rush. When to book pre-winter HVAC maintenance explains the timing. To schedule a tune-up with ZK Mechanical anywhere across the GTA and Hamilton, book online or call (647) 801-1252.