Geothermal systems are becoming much more common but they generally do require a "significant" amount of real estate and you often cannot build anything over the top of them (similar to septic fields). You'd probably have to talk with an installer to see if you have enough property to effectively use one of these systems but per the attached reference Florida is one of the locations where these systems are most common. My experience is these are very good solutions.
5 Things You Should Know about Geothermal Heat Pumps | Department of Energy