Free Tool

Series Parallel R-Value Calculator

Calculate the average R-value of an assembly


Wouldn't it be nice if you could push a button and see how much of a hit the R-value of a building assembly takes when you change the amount of exterior insulation, move the studs closer together, or leave an attic hatch uninsulated?


That's what this spreadsheet does. Incorporating the physics of series and parallel heat flow, it allows you to play around with the parameters in floors, walls, and ceilings to see what happens to the average R-value of the assembly. It's great for anyone who makes decisions about how much insulation to use, where to put it, or how assemblies are designed and built.

About the Author

Allison bailes headshot square.jpg?ixlib=rb 1.1
Allison Bailes III, PhD
President, Energy Vanguard

Allison A. Bailes III, PhD, is founder and owner of Energy Vanguard in Decatur, Georgia. Like many in the field of building science and green building, he is multi-faceted: His academic credentials in physics (BS, MS, MST, and PhD all in that field) give him a solid foundation in the science that underlies buildings. Having taught physics at the high school and college...[more]

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This tool is used in HeatSpring's ASHRAE 62.2 Ventilation for Single-Family Dwellings course.

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