I hope this doesn't lean toward the DIY side of things. My intent
is to provice the homeowner with some info so as to compare the Contractor's
write ups.

In my case, a three ton HP was installed along with ducting that supports two tons in a house that had no central heat/AC. Yikes

I had a contractor recently come to give an estimate to replace the HP with a split system using a gas furnace. Price was good. In general conversation , wifey mentions a possible lawsuit to the original install contractor. His response was buyer beware. What's that all about? Needless to say he won't be getting the job

The Charts and Calculators were an immediate help to me