Stretch Code

Photo by Ian Johnson

Standards for building energy systems and energy efficiency are set at the state level through Maine’s Uniform Building and Energy Code (MUBEC). In 2020,the Portland and South Portland Sustainability Offices joined with other clean energy advocates to successfully advocate for the legislature to allow municipalities to adopt a stricter “stretch” code that will create a pathway to net-zero energy buildings over the next decade. By ordinance, Portland and South Portland are required to adopt the “stretch” code, in lieu of the state’s base code, whenever the MUBEC updates its code and standards .

Maine’s energy code is based on the International Energy Conservation Code (IECC), which is amended every three years, and with each new version, more efficient materials, technologies, and techniques are specified in the code. The State law passed in 2025 updated Maine’s energy code from the IECC 2015 version to the IECC 2021. This code update went into effect for all Maine municipalities on April 7, 2025, and applies to all new residential and commercial construction, as well as many renovations of existing structures. With the new MUBEC, the stretch code will now require all buildings constructed or renovated in Portland and South Portland to exceed the 2021 IECC by 15%. 

As stated in our One Climate Future plan, building codes are the single most powerful tool that states and cities have to require higher levels of performance from new buildings. The adoption of the stretch code ensures that new and renovated buildings are built to a level of performance that will create an energy efficient building and lower potential greenhouse gas emissions. With existing buildings contributing 66% of both Portland and South Portland’s total greenhouse gas emissions, more efficient building codes, such as the stretch code, are a great way to reduce the amount of wasted energy, lower future energy bills, and reduce greenhouse gas emissions that contribute to climate change.