Why is it more efficient to air condition stores like Walmart with tall ceilings but less efficient to air condition homes with tall ceilings?

Question

I also remember hearing that old houses in FL were built with tall ceilings to help cool it off… which seems the opposite of what’s most efficient for home A/C’s??? Feels like I’m missing something.

In: 15

Answer 1

Hot air rises, so without AC a high ceiling can give more space for that hot air to sit in without people being exposed to it. So before AC, higher ceilings could make a room feel cooler. After the advent of AC this changed as outlined in other posts.