I want to replace my 20+ years old 5-ton AC system and furnace, and in the process would like to turn our first floor and second floor into two separate zones. There appear to be two choices: (1) create two separate systems, or (2) replace the current systems with an automatic zone control system such as the Lennox Harmony.
Does anyone have any thoughts on the pros or cons of either approach? Is automatic zone control riskier for retrofttting an existing system and ductwork?
Thanks in advance for your assistance.