Originally Posted by
hangfirew8
No, I never said that. IMHO zoning should only be done if a.) you have some real challenges to heat/cool a single house with a single unit and b.) you have a contractor that has done it before, done it often, and done it right.
Like I said, you can often lower the temp differential in a home by cheaper methods- such as addressing balancing, return size, higher flow return grills, more open diffusers, adding returns, adding radiant barrier and/or attic insulation, sealing existing duct, etc.
So, you clearly don't have b.)
Never push a contractor beyond their capabilities. Just get another.
I guess I'm having a problem discerning what is the real issue here. The original question involved fitting a 3.5 ton where a 2.5 was. Unless the builder oddly sized ductwork for a 3.5 ton, and then accidently installed a 2.5, I think that is a bad idea.
Now what is the real problem, besides replacing your old 2.5, do you just need a new working system, or do you also have a real problem with the heat differential between floors you are trying to solve at the same time?
-HF