What is the max square feet or cubic feet for residential air conditioners?

I don’t know why I am having so much trouble researching this on my own. Years ago I remember someone telling me if a house was over 2500 sq. ft. you needed two zones. I assume cubic feet actually matter more than square feet, but I really know very little about it.

What is the standard rule? I want two zones in my house so I only heat my bedroom suite during the winter to sleep at night. What I don’t know is if the rest of the house will be too large a zone on it’s own. I think the rest of the house is probably 2500 sq. ft. more or less, but the foyer has a 16 ft. ceiling, and the great room and dining is 12 ft. The rest of the house has 10 ft ceilings.