It would be great to have an equation to calculate annual heating and cooling costs, however, there are too many variables.  Tree coverage, amount of insulation, windows, energy efficiency of equipment, usage and climate all play a role.  The bottom line is that in almost every possible Florida environment, concrete masonry buildings are less expensive to heat and cool.  Much of this energy efficiency is attributed to the mass of a concrete block wall.

 

Mass allows a wall to store and dissipate heat.  In Florida, a concrete wall takes advantages of differences in night and day temperature by responding to changes very slowly.  As a result, less energy is required to maintain a comfortable constant temperature inside your building.