I am the second owner of a 3500 sq. ft. single story home with a ClimateMaster Tranquility 27 model TTV049 heat pump. The home was built for a disabled man and his elderly relative caregiver. From what I am told, the home originally had two heating zones. The smaller zone was an enclosed porch that represented about 10% of the footprint of the house. It was intended to be an exercise room and contain a hot tub of sorts, so a separate zone made sense. At some later date, the owner decided that he like cool temperatures and the caregiver liked very warm temperatures. The HVAC system of the home was then subdivided into two zones. Each of these two zones contained two bedrooms (and their bathrooms), and I assume that the bedroom doors were often closed (and have return ducts in each bedroom), but we tend to leave them open. The bedrooms are on opposite sides of the house. The middle of the house is an "open concept" with a common air return in the hallway. Heating ducts from one zone supply the kitchen, about 2/3 of the living room and one end of the hallway. Heating ducts from the other zone supply the dining room, the study, about 1/3 of the living room and the other end of the hallway. We tend to keep the two zones in the main part of the house at about the same temperature with the porch being kept cooler in the winter and warmer in the summer. Since there isn't a physical separation between the two main zones, I wonder if the system would be more efficient and/or comfortable is we disabled one of the thermostats so that the house would revert back to two zone (the porch and everything else.) The zone dampers are two wire (spring open and power close). Would both dampers remain open all the time if I set one thermostat (Honeywell TH8320's) to "off" or "cool" (during the heating season?) The zone control board is located on the heat pump which is in the attic. I know that I could just disconnect a wire to one zone damper, but I would prefer to avoid this.