I want to put some money back into the pockets of some of my builder and homeowner clients, so I wrote this post. If I can communicate back to my clients what is actually required for Energy Compliance (Energy Forms), then maybe someone out there will benefit from it. If the feedback is positive, my intentions are to continue these energy compliance related ‘money saving tips’ for my Energy Form clients.
Wall insulation values in Florida usually range between R-11 and R-19 for wood-framed exterior walls. The Florida Energy Compliance code allows what is called a ‘trade off method’ when performing the energy form computations. This allowing some flexibility as to how much R-value you actually need to design into your wall system. I want to dispel any thinking out there along the lines of: ‘I have to have at least an R-value of 13 or 19 in order to be safe when the inspector rolls around’. Not true. There’s flexibility in the energy compliance computations, and you may be surprised to know just how much you need to provide at a minimum.
For the truly energy conscious, R-19 wall insulation is for you. If you intend to use batts, keep in mind that R-19 batts will not fit inside a 2×4 wood-framed wall cavity because the R-19 batt insulation is 6 inches thick. You will have to build your exterior walls with 2×6 studs in order for the R-19 batts to properly fit, and that can drive the cost up. Consider using icynen (spray-in foam) instead of batts if R-19 in the walls is required. The icynene spray-in foam insulation only takes 3 1/2 inches of the foam thickness to achieve the same R-19 value. That means staying with a 2 x4 stud wall system, and that could keep money in your pocket. For those only concerned with constructing to meet Florida Energy Compliance, then R-13 in the walls is enough to pass in almost every case. For new construction I would recommend icynene foam over batts for superior sealing qualities.