Building & Energy Codes

Building codes provide standards for building construction and maintenance throughout the state that promote safety, public health, efficiency, and more. In particular, energy codes establish standards for energy efficiency, embodied carbon, beneficial electrification, weatherization, and more.  

MUBEC 

The Maine Uniform Building and Energy Code (MUBEC) is the statewide building and energy code that is comprised of codes from the International Code Council (ICC), the American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE), and the American Society for Testing and Materials (ASTM). The MUBEC applies to all buildings constructed or renovated in Maine. The MUBEC must be enforced in any municipality with a population of 4,000 residents or greater. If the population is under 4,000, the municipality may choose whether or not to enforce the MUBEC.

In addition to the base MUBEC, Maine is also required to adopt a stretch code. A stretch code is an alternative building energy code adopted and maintained by the board as an appendix to the MUBEC. Stretch codes are more stringent than base codes in terms of energy efficiency, carbon reductions, and resilience.  While no municipality can enforce a building code other than the MUBEC, municipalities may opt to adopt the MUBEC stretch code as their base code. Some communities in Maine that have done so include Portland, South Portland, and Freeport.  

Current Codes 

Pursuant to 10 MRSA §9722 6.B, MUBEC is required to ensure that both the ICC and ASHRAE codes are either the most recent edition or the edition previous to the most recent edition. ICC currently releases code revisions every three years with the most recent edition being 2021 ICC. The updated MUBEC codes can be found under the MUBEC Rules and Laws. The following codes and standards are in effect in Maine as of April 7, 2025:

  • ICC 
    • 2021 International Residential Code (IRC) 
    • 2021 International Building Code (IBC) 
    • 2021 International Existing Building Code (IEBC) 
    • 2021 International Energy Conservation Code (IECC) 
    • 2021 International Mechanical Code (IMC) 
    • Stretch Code 
      • The 2021 Stretch Code is created to lower energy consumption in both commercial and residential projects compared to the 2021 IECC. 
    • Commercial Projects: The Total Building UA for the project, calculated as outlined in C402.1.5, shall exceed the UA requirements by at least 15% over a code compliant project.  This means that the Envelope PASSES design by 15% better (or more) than code per the COMCheck compliance calculation. 
    • Residential Projects: The Total Building UA for the project, calculated as outlined in R402.1.5, shall exceed the UA requirements by at least 15% over a code compliant project.  This means that the Envelope PASSES design by 15% better (or more) than code per the RESCheck compliance calculation.  For residential projects that do not include fossil fuels for any use (heating, cooling, hot water, backup heat, cooking, etc) the Total Building UA shall exceed the UA requirements by at least 10% over a code compliant project. This electrification incentive allows the use of fossil fuels for backup power generation. 
  • ASHRAE 
    • 62.1 - 2019 (Ventilation for Acceptable Indoor Air Quality) 
    • 62.2 - 2019 (Ventilation and Acceptable Indoor Air Quality in Low-Rise Residential Buildings) 
    • 90.1 - 2019 (Energy Standard for Buildings except Low-Rise Residential Buildings) editions without addenda 
  • ASTM 
    • E-1465-2008, Standard Practice for Radon Control Options for the Design and Construction of New Low-Rise Residential Buildings 

Support

Energy Code Trainings 

In 2025 through the Clean Energy Partnership, GEO is funding passivhausMAINE's efforts to deliver energy code training sessions for Maine people. These trainings will teach new and experienced builders and code enforcement officers how to meet the new MUBEC building and health codes as well as understand and implement the most effective and modern practices for building long-lasting, low-carbon structures. Upcoming trainings will be held in: 

Visit this page for a full list of upcoming training dates and locations. Check this page again soon as more trainings opportunities will be listed here.