The NJ Uniform Construction Code references two primary ICC codes for residential energy efficiency: 2018 IRC and 2018 IECC.
The energy provisions in these two codes are nearly identical. They can be used interchangably for compliance.
The 2018 IECC and IRC were not adopted in their entirety. Bulletin 19-2 released by the NJ Department of Community Affairs includes a number of additions, deletions, and modifications. It would be useful for NJ construction professionals if the state would release modified versions of these codes that incorporate all of the changes, like NY has done. However, no such all-in-one NJ-specific codes exist, so it is left to professionals to pore through the various documents to understands the details.
The IECC and IRC provide various options for compliance. These include simple prescriptive tables listing insulation levels, as well as flexible pathways that allow builders to tradeoff improved performance in one area (e.g. ceiling insulation) for reduced performance in another area (e.g. wall insulation).
