The Florida Energy Code is contained in Chapter 13 of the unified Florida Building Code. The Code is mandatory for all new residential and commercial construction as well as additions to structures. The Energy Code is Performance-based rather than Prescriptive-based, with minor exceptions.

The term Performance-based means that the whole house energy characteristics are all taken into account and calculated. The characteristics are then entered into the State-mandated software to produce what is called an e-ratio. E-ratio is simply a ratio of how this house compares to a geometric twin of that house that would be the minimum acceptable to exactly pass the code. The minimum house is called a baseline house compared to the characteristics of the actual house to be constructed, which is referred to as the as-built house. Any e-ratio less than 1.00 will pass the code. An e-ratio greater than 1.00 does not pass the code.

A simple way to conceptualize the code is to equate a house with having an energy budget, based upon the base line house. The total budget cannot be exceeded, but you can allocate resources to some measures of the house (for example adding insulation while reducing the efficiency of windows) as long as the total energy budget is not exceeded.

There are only two major exceptions (prescriptive measures) of note that cannot be violated. A new construction house must have at a minimum a 13 SEER rated air conditioning system and ceiling insulation cannot be less than R19. There is much misinformation from contractors and certain industries that market building products and materials. Much of this information falsely indicates that their product or upgrades must be used in order to comply with code. Notwithstanding the two notable exceptions mentioned above, THIS IS NOT TRUE.