[PJ_Smiley]

In our previous designer home in TV, we added additional living space and expanded and enclosed the lanai. After adding additional space we had approximately 2,200 square feet in the house and 420 square feet (30x14) on the lanai. We decided to upgrade the A/C and had four zones set up, each with its own thermostat. The four zones - main area (living, dining, entrance, kitchen, breakfast nook), master suite, lanai, and 2 guest bedrooms and bath. At night we could lower temperatures in master and not affect the other areas. If someone was in the guest bedrooms, they could adjust the temperature to whatever they wanted. Also, originally the single thermostat was in the hallway leading to bedroom that had the main, large return vent in the ceiling above the hallway. When we split to 4 zones, we moved that thermostat to the entrance wall closer to the living room, so it would be in the center of that zone. One nice thing about the TV designer house was it had return vents in each room (not bathrooms or closet). That made the zoning practical, because each zone needs a return vent. In a prior home we built in south Florida, there was a main return vent in the center of the house and a small return vent in the master bedroom - none in other rooms. A zoned A/C would not have been feasible.

Additional Sumter County information: To add A/C to lanai, we had to remove existing concrete floor and add vapor barrier and new concrete. This also worked best because we wanted the lanai floor level. We left the new concrete floor the same level at the sliding doors and below the main flooring because we wanted the extra 3-4 inches in ceiling height. The lanai ceiling is only about 8 ft high. Also, we had to add electric outlets per code to be able to upgrade the lanai to allow for A/C. We installed new lighting and fans (not required) and a floor outlet near the exterior window side to allow for a lamp next to sofa. Since we expanded the width of the lanai, we installed electric outlets in the new columns - code, not sure, but we added for convenience. I believe this made the lanai a class 5 addition per Sumter County code.
We left the sliding doors. Here's where most folks are misinformed. We did not add the 420 sqft on A/C lanai to our square footage for the property appraiser. The square footage for the A/C lanai is only counted if the sliding doors are removed. Leveling the floor does not count. Adding A/C does not count. Only removing the sliders makes the lanai additional square footage for the property appraiser.
The above does not apply to the A/C mini-split. The mini-split is considered a dehumidifier and is exempt.

An additional thought: When we listed the house for sale, we listed it as 2,200 sqft under area with a 4-zone A/C. Lanai is 420 sqft and has a separate zone for A/C. That way it matched Sumter County Property Appraiser website for square footage.