Integrated Heat and Moisture Calculation Tool for Building Envelopes

Design more energy-efficient building envelopes with the ability to design moisture control to improve energy efficiency of building envelopes.

Lawrence Berkeley National Laboratory


Berkeley, CA

Recipient Location


Senate District


Assembly District



Amount Spent



Project Status

Project Result

The existing THERM software already had a large, established user community of professionals, academics, and researchers using the tool for rating windows and buildings. The team continues to use web-based forums to disseminate information and request testing from users. The research team is currently testing and doing verification of THERM-M and made the software tool more user friendly and fixing bugs in the software based on user feedback. The draft final report is under review. The team continues to inform potential users at conferences and industry gatherings regarding the project results. The web page with the latest version of THERM-M, as well as documentation, including technical documentation is located on the LBNL Therm 8 / Window 8 web page. (

The Issue

To mitigate negative effects of accelerated global climate change, ZNE buildings are being built with highly insulated and very tight envelopes. This could cause moisture to build up inside buildings. By failing to account for the moisture characteristics in the thermal envelope, designers and builders can introduce moisture-related problems that endanger the health and safety of building occupants as well as the durability of the building itself. It is important to solve the problems of designing and constructing building envelopes that are correctly detailed for ensuring excellent thermal performance without introducing moisture problems.

Project Innovation

This project's purpose is to enhance the existing software tool widely used by building designers for thermal envelope modeling. The existing modeling software is used in Title 24 and Energy Plus development. It is an official tool by National Fenestration Rating Council, Passive House Institute, and Window Attachment Energy Rating Council. The new software tool, integrates both thermal and moisture modeling to improve envelope design and analysis for new construction and retrofit applications.

Project Benefits

The development of the user-friendly modeling software tool enables improved design to building envelopes. The integration of both thermal and moisture modeling is expected to improve envelope energy efficiency and prolong the life of buildings.
Building envelopes are responsible for approximately 0.37 quads (equivalent to approximately $4 billion annually) in California's residential and commercial buildings and nationally, envelopes are responsible for approximately 7.6 quads (approximately $80 billion annually). It is estimated that a 5% improvement in building envelope energy performance can be attributed to more confident building envelope design, resulting in 0.02 quads (approximately $200 million annually) in energy savings in California and 0.38 quads (approximately $4 billion annually) nationally.

Key Project Members

Project Member

D. Charlie Curcija


Contact the Team