The New Buildings Institute (NBI) recently released a model stretch building code that targets 20% better efficiency than current national building energy codes. The new 20% Stretch Code offers jurisdictions a set of energy-saving building strategies that cover design aspects such as envelope, mechanical, water heating, lighting and plug loads.

The 20% Stretch Code is one of a set of building codes being developed by NBI that provide increasing stringency. The set gives cities and states the basis for maximizing energy savings in both commercial and residential projects over the course of several code development cycles allowing the market to prepare and gain experience with new efficiency practices and technologies.

The stretch code is designed as an “overlay” code to integrate with existing national model energy codes for residential and commercial construction, such as the International Energy Conservation Code (IECC) and the American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) Standard 90.1. Cities and states can choose to adopt the entire stretch code or parts of it through their existing code review process. It generally takes legislative action, or state or local code council approval for new building codes to be adopted. State and local governments can also make stretch code adoption voluntary, and incentivize owners and builders to follow the code.

The model code was designed to exceed 90.1-2013 by 20%, but I’m not sure how it fares compared to 90.1-2016, which achieved energy savings, with a significant lighting contribution.