Energy codes are one of the first regulatory hurdles you need to identify during programming. They govern how buildings use energy across the envelope, HVAC, lighting, and service water heating systems. Two codes dominate the field: the International Energy Conservation Code (IECC) and ASHRAE Standard 90.1.

The IECC covers both residential and commercial buildings. ASHRAE 90.1 applies specifically to commercial construction, though many jurisdictions reference it through the IECC rather than adopting it directly. Both codes update on a three-year cycle, and the version your project must follow depends entirely on what the local jurisdiction has adopted.

Each code offers multiple compliance paths. You can follow prescriptive requirements that spell out exact values for insulation, fenestration, and equipment efficiency. Or you can take a performance-based approach that uses energy modeling to demonstrate your design meets or beats a baseline building. There are also envelope tradeoff paths and whole-building performance methods in between.

Climate zones are the backbone of energy code requirements. The United States is divided into eight temperature zones with moisture regime subcategories (A, B, and C), and every prescriptive value in the code ties back to these zones. Getting the climate zone right during programming sets the stage for every energy-related design decision that follows.

For the ARE, you need to understand how to identify the applicable energy code, distinguish between compliance paths, and recognize how energy codes interact with green building rating systems and stretch codes.