We are in the process of purchasing a new furnace and A/C. What is the differance between a chimney vented furnace and single stage/two stage PVC vented furnace?

The difference is efficiency, meaning that more heat is given to the house from the PVC vented unit than would be if some heat was thrown into the chimney to make the exhaust work.

In the PVC (or better yet, stainless) vent some small electrical use with an electric fan is used to exhaust gases and make a more precise controlled burning of the fuel. When furnaces get over 87% AFUE efficiency they don't have enough heat left over to go out of the furnace to make chimney gases rise, so an electric fan is required.

You can see the difference in efficiency in the literature describing the different furnaces.

www.heatpro.us energy businessmen's knowledge

Yes, you really have to find out the MAKE and MODEL to get good answers. There IS more than one machine made.

Thank you for your input and explanation.