Inspected a home with a zoned HVAC system that had a thermostat at the downstairs and one at the upstairs to control the different zones. This is fairly common in my area. This was a one year old house. I typically operate the zones independently and then at the same time to see that they are functioning properly.

Usually the upstairs zone is independent of the downstairs zone, with each area being controlled by the thermostat in the zone. On this system however, with the upstairs thermostat in the off position, I operated the downstairs thermostat on heat mode and when I went upstairs I found that the game room area (which is open to the downstair area via balcony railing) and one upstairs bedroom were controlled by the downstairs thermostat. All other upstairs registers/ducts were not blowing because the upstairs thermostat was off.

On the majority of the newer homes I have inspected, the upstairs and downstairs zones have always been indepenent of each other. Other than the inconvenience issue of having to go downstairs to adjust temperature for two rooms of the upstairs area, could this also affect the balance of the system or have other potential issues?

Comments welcome.

Eric