The 20% Stretch Code, a new set of standards developed by New Buildings Institute (NBI), offers a tool for accelerating the use of more energy efficient designs in new buildings.
Most new buildings are constructed to meet only the minimum energy efficiency requirements in state or local building codes that are often based upon national model codes such as the International Energy Conservation Code and ASHRAE 90.1.The stretch code provides a way for localities to move ahead more quickly with greener standards than they would by simply adopting national building codes.
The adoption of national building codes by states can be a slow, erratic process. Some states are still using codes that are up to three development cycles behind the most recent codes, representing design and construction practices from 2009. Stretch codes can also be adopted as voluntary codes or policies that can be fostered by devising incentives for designers and builders to use them.
As of October 2017, 214 municipalities have adopted the stretch code.