Heat Pump & Furnace System Selector

First, the furnace. Standard efficiency furnaces (80% AFUE) vent through a metal flue pipe. High efficiency furnaces (92% AFUE and up) vent through white PVC pipe and need a condensate drain.

Step 3: Furnace efficiency

Standard Efficiency: Metal Flue80% AFUE. Lower upfront cost and the simplest swap if your current furnace vents through a metal pipe.662 systems, from $3,071 High Efficiency: PVC Flue92% to 97% AFUE. Lower gas bills, and the best fit for colder climates.683 systems, from $3,529

How to tell what you have. Look at the pipe coming out of the top or side of your furnace. Metal pipe usually means standard efficiency. White PVC usually means high efficiency.

Safety. A high efficiency furnace must never vent into an old metal flue, and a standard efficiency furnace must never vent through PVC. The flue gases from an 80% furnace are hot enough to melt PVC, which can leak carbon monoxide into the house. When in doubt, match what you have and have the venting checked by a licensed installer.

Not sure what you have? Send us a photo of the data plate on your outdoor unit and furnace, or call our team in Winder, GA at (877) 843-4822. Free shipping on orders over $99, and financing is available at checkout through Affirm. Need help with size? Try the sizing tool.