Furnace type
Mid-efficiency (80%) furnaces
Mid-efficiency furnaces around 80% AFUE are the non-condensing furnaces that dominate older Canadian homes. They are no longer sold for standard residential installations, but millions remain in service, which is why this site documents them for repair context: metal venting, no condensate, and different failure patterns.
Short answer
An 80%-class furnace does not condense: it vents through metal pipe or a chimney, makes no condensate, and was the standard until the 95% AFUE minimum took effect for furnaces manufactured on or after July 3, 2019. Existing mid-efficiency furnaces can be repaired and maintained, but when they are replaced, the new furnace is condensing, which means new plastic venting and a condensate drain.
The regulation and the installed base
NRCan's Energy Efficiency Regulations set a 95% AFUE minimum for standard residential gas furnaces manufactured on or after July 3, 2019. Furnaces built before that remain legal to operate, and repair parts and service for them are part of what this site documents (historical series and their manuals).
How they differ in service
Mid-efficiency furnaces are simpler in the condensate department (none) and venting (metal, often shared with a water heater), but their heat exchangers run hotter and their ignition and airflow systems age like any furnace. Codes and controls are generation-specific; the historical series pages on this site keep each one's documentation separate.
The replacement conversation
When an 80% furnace fails beyond economical repair, the replacement is a condensing furnace, and the job includes the venting change, condensate routing, and any chimney work for the water heater that shared the old flue. The gas saving is roughly 15 to 18 cents per dollar of fuel compared with an 80% unit, before considering the new system's other costs.
Related
Questions people ask
Is it illegal to still use my 80% furnace?
No. The regulation applies to manufacture, not to operation. Older furnaces can be serviced and repaired; only new standard residential installations must meet 95%.
Should I replace my working 80% furnace now?
A working furnace with a healthy heat exchanger is usually worth keeping and repairing. The replacement math changes when it fails, when the heat exchanger is compromised, or when repairs get frequent.
Can my 80% furnace share the chimney with the water heater after I add a heat pump?
The chimney arrangement matters whenever one appliance changes. A replacement furnace leaves the chimney; the water heater then needs its own venting path, sized correctly. The assessment covers it.
Need this looked at?
Call BC Wide with the brand, model number and anything on the display. Or
Request service online with this page attached.