Building codes establish the minimum legal requirements for buildings. There are typically two types—prescriptive and performance.
Prescriptive codes tell a designer what must be done (such as requiring R-20 insulation in the walls). Performance codes simply provide a metric that must be met (such as total energy use relative to a baseline), allowing the project to meet that benchmark in a variety of ways.
Code requirements differ from locale to locale, so here we cover news related to sustainability or energy use in building codes, and ways in which innovative green technologies are limited by code requirements.