All "zoning" is is the abiliity to control the temperature of several areas of the house, thus "zones".
Originally posted by seabreeze
I have got the same problem. I have a 20 year old 2000 sq ft house with 4 bedrooms upstairs and fairly new Trane heat pump (xr11). Tried attic exhaust fan but that was not much help. I am located in mideastern region which can be hot and humid in summer. Have original blown fiberglass insulation in attic and would be willing to try cellulose on top. What is involved in zoning and is it usually expensive to add on ? Does it require two separate heat pump systems or just two thermostats ?