The Technical, Practical, Applied & Operational Principles of Building Science – GreenBuildingAdvisor

By RANDY WILLIAMS | January 5, 2026

Ask ten industry pros what building science means, and you’re likely to get ten different answers. Personally, I like the short answer, “the study of energy and moisture in buildings.” This can be expanded to the scientific study of buildings as interdisciplinary systems, focusing on heat, air, and moisture—the “HAM sandwich” as Josh Salinger likes to call it.

If we want to get technical, building science is the study of how buildings work—how heat, air, and moisture move through a structure, how materials interact, and how those interactions affect durability, comfort, indoor air quality, energy use and resilience.

I think it’s helpful to break building science into four distinct lanes because each one handles a different responsibility: understanding, designing and building, verifying, and ultimately operating the home. And as homes become tighter, more complex, and more dependent on mechanical systems, building science needs a clearer framework—one that shows who is responsible for what.