RSL is not listed on NFRC for entry doors because only whole systems can be certified. However, we have done all of the simulations and are ready to help our clients through the certification process.

How to calculate an IG unit’s R-Value (insulation unit of measure):
Divide the number 1 by the U-Value of the unit, e.g. a 22 x 36 ½” Clear unit has a U-Value of 0.29. 1/0.29= 3.45 (R-Value).