Calculation of R and U insulation values Energy3D Forum › Forums › Energy3D Questions › Calculation of R and U insulation values This topic contains 1 reply, has 2 voices, and was last updated by Charles Xie 1 week ago. Viewing 2 posts - 1 through 2 (of 2 total) Author Posts November 28, 2019 at 11:21 am #149 GLDIIIParticipant Can you discuss what else is part of the conversion between R value and U value in Energy 3D. Thanks. November 28, 2019 at 3:59 pm #150 Charles XieKeymaster The R-value to U-value conversion is based on Wikipedia’s definition: U=1/R=k/L where k is the material’s coefficient of thermal conductivity and L is its thickness. Author Posts Viewing 2 posts - 1 through 2 (of 2 total) You must be logged in to reply to this topic.