Solar Vs. Thermal Envelope Case Study: Florida

The Florida Building Commission released a memo in April, “Renewable Energy Trade-Offs in the Building Energy Code” that reviews what would happen if onsite generation is allowed for compliance in the Florida Building Code.

Florida encompasses two climate zones for purposes of building energy code compliance—Climate Zones 1 and 2.
For those climate zones, the IECC establishes an ERI compliance target of 52. This target was modified, however by Florida HB 535, to an index of 58 in both climate zones.

If on-site generation is allowed for compliance in the Florida Building Code, there is a very real possibility that homes will be constructed that meet only minimum efficiency standards and still meet the ERI target. For example, a home built in Tallahassee to minimum 2015 prescriptive standards and the 2009 thermal envelope standards receives a failing score of 86. That same State Choices home with 5 kW of solar panels achieves a passing score of 45.

This video does a great job explaining the situation in Florida: