I have a 100 year old, 2 story brick home in S.E. Wisconsin with 2,000 square feet and 9' ceilings. I am replacing a 25 year old, 100,000 BTU Lennox Pulse furnace with a Carrier Furnace that qualifies for the tax credit - Infinity ICS, Infinity 96, Performance 95 or Comfort 95.
The ductwork will remain the same with the supply lines located on the interior walls and the return lines on the exterior. This is how the home was originally built.
For the specifics shown above - particularly the duct set-up - are there any advantages/disadvantages to having multi heat stages and variable speed blowers as found in the Infinity models vs. 1 or 2 stage heating and specific blower speeds as offered in the Performance or Comfort series?
Also, if in between sizes - is bigger better?