By Mario Vaghei, General Manager, Aire One Peel Heating & Cooling · Published November 11, 2026 · Facts verified November 10, 2026
Short answer
A furnace tune-up is a yearly visit in which a technician inspects, cleans and tests the furnace before the heating season. Carrier's own checklist runs to eleven items: the blower, heat exchanger, burners, electrical connections and venting are inspected, the unit is cleaned, the filter is checked, moving parts are lubricated, the safety controls and carbon monoxide levels are tested, the thermostat is calibrated, combustion is analyzed, the ductwork is checked, the furnace is run through its cycles, efficiency is measured and you get a written report. Enbridge Gas tells Ontario homeowners to book that inspection once a year with a TSSA-registered HVAC contractor.
On this page
What a furnace tune-up is, and what it is not · The furnace tune-up checklist · What you can do yourself between visits · Two things to look for on the report · When to book · Frequently asked questions
What a furnace tune-up is, and what it is not
Carrier describes a tune-up as professional maintenance to be done "at least once a year", ideally in early fall before the heating season, and again after any major repair. It is an inspection, a cleaning and a set of tests. It is not a repair: if the technician finds a cracked heat exchanger or a failing part, that work is quoted separately, which is why Carrier's eleventh item is a report with recommendations.
Natural Resources Canada frames the timing the same way: "It's a good idea to schedule a check-up with a contractor as the seasons begin to change", with the heating check-up in the fall and the cooling check-up in the spring, done by a professional, insured contractor. If you only want to know how often a furnace should be serviced, that question has its own guide.
The furnace tune-up checklist
| Item | What the technician does | Why it matters |
|---|---|---|
| Filter | Checks the air filter and cleans or replaces it | A clogged filter restricts airflow and, in Carrier's words, affects "your comfort and your system's efficiency" |
| Thermostat | Checks operation and calibrates it | A thermostat that reads wrong runs the furnace too long or not enough |
| Heat exchanger | Cleans it and checks "for cracks, holes, or leaks" | A cracked heat exchanger can let combustion gases, including carbon monoxide, into the house air |
| Burners and crossover | Cleans and adjusts them | A dirty burner makes the system "less safe and less efficient" (NRCan) |
| Gas valve and gas pressure | Checks and adjusts the valve; checks gas connections and pressure | Correct pressure is what the burner was designed for |
| Gas line and fuel supply | Checks for leaks in the gas line and other fuel-supply components | A leak is a safety fault, not an efficiency item |
| Combustion | Analyzes the air-fuel mixture and measures combustion efficiency | Confirms the furnace is burning cleanly and efficiently |
| Safety controls and CO | Tests the safety controls, checks for carbon monoxide and confirms venting works | The part of the visit that protects the people in the house |
| Venting and flue | Inspects the flue pipe; Enbridge adds that vents must "terminate outdoors and are not cracked, corroded or blocked" | Blocked or corroded venting can push exhaust back indoors |
| Blower and motor | Inspects and cleans the blower and blower motor; lubricates moving parts | Friction and dirt raise the energy the furnace uses to move air |
| Electrical | Tightens connections, measures voltage and current on motors, looks for burned wires or heat damage | Loose or burned connections fail on the coldest night |
| Performance test | Runs the furnace through heating cycles and records return and supply air temperatures | Shows whether the furnace delivers the heat it is rated for |
Table: Carrier Canada, "Furnace Tune-Up Guide" and "Guide to Annual Furnace Maintenance"; Natural Resources Canada, "Guide to maintaining your home heating and cooling system"; Enbridge Gas, "Natural gas appliance safety". Read November 10, 2026. Older furnaces with a standing pilot get one more item: the pilot system is evaluated, cleaned and tuned.
What you can do yourself between visits
- Change or clean the filter. Carrier says every one to three months; Enbridge says at least every three months. Follow the owner's manual for your filter type.
- Keep supply and return vents clear and clean, and keep the area around the furnace clear of stored items.
- Check the thermostat works and holds its schedule.
- Test your carbon monoxide alarms monthly, as Enbridge recommends, and replace them on the manufacturer's schedule.
Everything that involves gas, combustion or the inside of the cabinet belongs to the technician. Enbridge Gas is clear that it "does not sell or repair furnaces, boilers or fireplaces": the inspection comes from a TSSA-registered contractor, not the utility.
Two things to look for on the report
- The heat exchanger line. Carrier lists "inspecting the heat exchanger for cracks" as part of the tune-up. Ask what was found and how it was inspected. If you want to know what a crack means for the house, read our guide to cracked heat exchangers.
- The combustion and carbon monoxide readings. A tune-up that produced no numbers did not include the combustion analysis Carrier describes.
If the report lists a furnace that short cycles, that is usually a sizing or airflow issue rather than a dirty part.
When to book
Once a year, in early fall, before the first cold week, and again after a major repair. Aire One Peel's protection plans include an annual inspection on every tier, so plan members do not need to book it separately. If the furnace is already acting up, start with furnace repair in Mississauga instead of a tune-up. Call 905-564-8545.
Frequently asked questions
What is included in a furnace tune-up?
Carrier's checklist has eleven items: inspection of the blower, heat exchanger, burners, electrical connections and venting; cleaning; filter check; lubrication of moving parts; safety-control and carbon monoxide checks; thermostat calibration; combustion analysis; ductwork inspection; performance testing; an efficiency check; and a written report with recommendations.
How often should a furnace be tuned up?
Once a year. Carrier recommends it "at least once a year", ideally in early fall, and Enbridge Gas tells Ontario homeowners to "schedule a yearly furnace inspection with a TSSA-registered HVAC contractor."
Is a furnace tune-up the same as a furnace inspection?
An inspection is one part of a tune-up. A tune-up adds the cleaning, the combustion test, the thermostat calibration and the performance test. The yearly visit Enbridge recommends should include the inspection items in the table above.
Does a furnace tune-up include repairs?
Usually not. The visit ends with a report and recommendations; any part that failed the inspection is quoted and repaired separately.
Who should do a furnace tune-up in Ontario?
A TSSA-registered HVAC contractor. Gas, combustion and venting work in Ontario is done by registered contractors, and Enbridge Gas itself does not service furnaces.
Sources and references
- Carrier Canada, "Furnace Tune-Up Guide: Everything You Need To Know", read November 10, 2026.
- Carrier Canada, "Guide to Annual Furnace Maintenance", read November 10, 2026.
- Natural Resources Canada, "Guide to maintaining your home heating and cooling system", read November 10, 2026.
- Enbridge Gas, "Natural gas appliance safety", read November 10, 2026.