Furnace Venting Guide: B-Vent vs PVC for Minnesota Homeowners

Furnace Venting Guide: B-Vent vs. PVC for Minnesota Homeowners

When replacing a furnace, venting is one of the most important installation decisions—and it's directly tied to which efficiency tier you choose. Understanding the difference between B-vent and PVC venting systems helps you prepare your home and ask the right questions before installation day.

B-Vent (Standard Efficiency — 80% AFUE)

Standard 80% AFUE furnaces use B-vent: double-wall metal flue pipe that exhausts hot combustion gases up through the roof via a chimney or dedicated flue. Because the exhaust gases are still hot (300°F+), they create natural draft and rise through the pipe. B-vent installations are simpler in homes with existing chimneys, but the hot exhaust means more heat is wasted—which is why efficiency is limited to 80% AFUE.

PVC Venting (High Efficiency — 90%+ AFUE)

High-efficiency 90–96% AFUE furnaces extract so much heat that exhaust gases exit cool (100°F or below). Cool exhaust can't create natural draft, so these furnaces use a power inducer motor and vent through white PVC pipe instead of a metal flue. Two pipes are typically required: one for intake air and one for exhaust, both terminating through an exterior wall near the furnace. PVC venting is simpler to route but requires specific termination clearances from windows, doors, and meters.

Minnesota Venting Considerations

PVC vent terminations can ice over in extreme cold—a common Minnesota winter problem. Proper installation with correct clearance and termination elbows prevents this. See our condensate guide and pressure switch guide for related cold weather issues. Furnace Direct carries both 80% and 96% AFUE Goodman models.