For use with the International Code Council’s 2012 International Energy Conservation Code (IECC) or International Residential Code (IRC), this app provides wood solutions for the Total UA alternative method. Opaque wall U-factors are calculated based on improved fenestration performance. Either an unknown opaque wall or fenestration U-factor can be determined. The app also gives insulation requirements needed in various wall assemblies to achieve the opaque wall U-factor. Wall assemblies include