Lessons Learned: THERM and an Evolution of Wall Assemblies

By Mike Meade, AIA

Mike is a senior project architect with 18 years of experience and is a member of our in-house building enclosure committee, which provides envelope resources and technical support to our project teams. He sits on the board of the Portland Building Enclosure Council and is currently working on the PDX Terminal Balancing and Concourse E Extension project, discussed at the end of this post.

I attended a training from Passive House Canada on THERM software, which was developed at the Lawrence Berkeley National Lab for evaluating heat transfer through building components. Using THERM, you can model 2-D heat-transfer effects in components at building interfaces like windows, walls, foundations, roofs, and doors. Heat-transfer analysis allows you to evaluate a product’s energy efficiency and local temperature patterns, which may relate directly to problems with condensation, moisture damage, and structural integrity.

After the training, I was hungry to share the software and give our project teams a better way to evaluate details for thermal performance. I also thought about buildings I have built over my career. I’ve worked on buildings with many types of walls — some just to meet code, some just to meet the budget, and some to create the highest possible performance. I used THERM to evaluate these assemblies to see how we fared.

R-value measures the ability to prevent heat transfer. The higher the number, the better.

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