Furnace & AC in Ontario

A well-maintained natural gas furnace typically lasts 15-20 years in Ontario. Annual tune-ups extend furnace life - a technician cleans the heat exchanger, checks the burner, and tests carbon monoxide levels. If your furnace is over 15 years old and needs a major repair, replacement is often more cost-effective.

Furnaces are rated by Annual Fuel Utilization Efficiency (AFUE). Most Ontario homes benefit from a 96%+ AFUE condensing furnace. These use a secondary heat exchanger to recover additional heat from exhaust gases. Installation requires PVC venting rather than a metal flue - confirm your contractor accounts for this.

Consider replacing a central AC unit if it is over 12 years old and needs a major repair, or if it uses R-22 refrigerant (phased out in Canada). Modern AC units use R-410A or R-454B refrigerant and are substantially more efficient - SEER2 ratings above 16 can meaningfully reduce summer cooling costs.

A new high-efficiency gas furnace (96%+ AFUE) installed in Ontario typically costs $3,000-$8,000 including supply, installation, and any venting changes. Two-stage and modulating furnaces cost more but run more quietly and efficiently. If replacing both furnace and AC at the same time, combo pricing often saves $500-$1,500 over separate installations.

The best time to replace a furnace is spring or early fall - before winter demand peaks, lead times are shorter and contractors are more available. AC replacement is ideally done in spring before summer demand. Emergency mid-winter or mid-summer replacements are available but may have longer wait times.

Ask whether they pull required gas permits, how they size the equipment (a heat loss/gain calculation is the proper method), what warranties cover the equipment vs. the labour, and whether they will handle disposal of the old unit. For a new condensing furnace, confirm they are handling the new PVC flue and condensate drainage properly.