Madhatter, it is correct that the home had (and still does) a 2-ton
unit for the lower (main) level at the time of construction. At the
time of and just prior to purchase, a fifth 8" duct was installed at my
request, and I was way more ignorant then than I am now. The builder
did not point out the downfall of such a plan; he wanted to unload the
As I mentioned in the earlier thread, I have never been happy with the
cooling. Call me an idiot, I then added a basement and another 8" duct.
So, it appears that 2.5 is definitely called for, and perhaps 3, given
the two additional demands on the original unit as explained above.