HVAC DIY Tips & Tricks
If you have a furnace with a metal exhaust pipe, your furnace is considered a standard efficiency furnace and is approximately 70% efficient.
If your metal exhaust vent is routed out of the house, it’s likely a direct vent and uses an exhaust fan. This type of furnace is slightly more efficient at about 80%.
A high-efficiency furnace uses a primary and secondary heat exchanger to remove heat. This highly efficient furnace will use a single or double pipe vent design.
All propane and natural gas furnaces have the capability to be installed with two-pipe furnace venting. Two pipes are preferred as they won't use up the air in the room.
The combustion process may create carbon monoxide if the flue pipes are blocked or damaged. Other issues include cracking or failing joints.
Obviously, making a decision on what type of furnace to buy has more variables than just the venting system, but it’s definitely one to consider.