Serious Materialsseriousmaterials.com R-8, R-11, or R-14 insulating windows - R-values were tested across the glass, including the frame, and not just at center - Reported to triple the R-value of the frame compared to previous models - Insulated fiberglass frame
Serious Materialsseriousmaterials.com R-8, R-11, or R-14 insulating windows - R-values were tested across the glass, including the frame, and not just at center - Reported to triple the R-value of the frame compared to previous models - Insulated fiberglass frame