Updated Boundary Condition Library

Last Updated: 
Wednesday, September 6, 2017

Software/Versions Affected:

A few changes have been made to the THERM 6 Boundary Condition Library:

  • The Interior Frame Boundary Conditions for 20 degree tilt models has been corrected
  • Boundary Conditions have been added for NFRC CMA Spacers ("CMA Spacer Indoor" and "CMA Spacer Outdoor")

The Interior Frame Boundary Conditions for 20 Degree Tilt cases were wrong in the THERM 5 program, and also initial releases of THERM 6. The current release of THERM 6 has the correct values in the BC.LIB file.

Here is a comparison of the old (wrong) and new (correct) values:

Boundary Condition Name


Convective Film Coefficient (hc) W/m2K


Convective Film Coefficient (hc) W/m2K

Interior (20 Tilt) Wood/Vinyl Frame (convection only) 3.38 3.09
Interior (20 Tilt) Thermally Broken Aluminum Frame (convection only) 4.38 4.09
Interior (20 Tilt) Thermally Improved Aluminum Frame (convection only) 4.60 4.32
Interior (20 Tilt) Aluminum Frame (convection only) 4.94 4.65

BC-T6-20TiltFix-CMA.zip contains the new corrected values for these Boundary Conditions in a file called BC-T6-20TiltFix-CMA.lib. You can keep that name, and use the "Load" feature in the Boundary Condition Library to get the new values, or you can rename it to BC.LIB and put it in the appropriate directory (depending on your operating system) and overwrite your old (wrong) BC.LIB. Which method you choose will depend on whether you have made custom boundary conditions in your existing BC.LIB that would get overwritten if you replaced that BC.LIB with the new one.