Hello, my wife and I are building a two-story home in South Florida. We'd like to have a concrete plank for our floor system. However, our architect says that if we do this, we can't run ductwork downstairs through the concrete. The upstairs ductwork would come from the attic.

He suggested more soffits instead. Does anyone have any idea if this would be less efficient? Will we have issues keeping our downstairs cool?

Any other out of the box ideas?

Thank you very much!

The calculated load numbers and the floor plan might steer the answer one way or the other. The cooling & heating loads of first-floors tend to be a lot lower than top floors, and first floors often have fewer doored-off spaces. A right-sized split system for just the upstairs, and a right sized ductless minisplit for the lower floors might be a viable solution.