I agree with VT and other posters that say the savings for adding foam to block wall cavities post construction would not justify the expense. Listed below are some generalities for Florida power consumption for a home with electric power Heating and air conditioning.
Power Consumption
Heating and air conditioning 37%
Appliances and electric lights 50%
Hot water 13%
Your annual electric bill would be about 1000$ (CYV) to 2000$( large Designer) is my guesstimate based on owning houses in TV. Mr. Toymeister may have more precise data.
Your maximum savings would be maybe 1/3 of your Heat & AC cost since much of the solar heat gain in summer and heat loss in winter is through the windows and air infiltration. That savings of ~13% yields a savings of 130 to 260$ per year. Even if you saved it all, there is no way to justify adding foam to the block wall cavities after construction. You would need to drill a hole through your exterior stucco wall every 4 inches or so, inject expanding foam, then patch the holes, and finally repaint your house. Repainting alone is probably 2 to 3000$
Other sources indicate that the current TV block wall design has an R value of about 10.
Concrete block with air voids 2 to 2.5
3/4 inch foam fastened to inside of wall 5
sheetrock and airspace 2.2
Total R 9.2 to 9.7
Your double pane windows have an R value of 3 to 3.7 for comparison.
Other Comments
Solid concrete is a good conductor of both heat and sound. Not good for heat savings or reducing sound.
Heat saving and sound deadening materials are generally lighter and similar in nature foam, wall coverings, special batting installed with separations to reduce sound transmitted through the structure.
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