The thermal break
A polyamide strut is mechanically crimped between two aluminum profiles. It carries the structural load between them while conducting a fraction of the heat, which lowers the whole-unit U-factor and keeps the interior frame face closer to room temperature — the practical benefit being no condensation line along the frame on a humid morning.
U-factor and SHGC in plain terms
U-factor measures how fast heat moves through the whole assembly. Lower is better, and it is the number that matters most in a heating climate. SHGC measures how much of the sun's energy the glass lets through. In Florida that is usually the more important of the two: a lower SHGC keeps solar load out of the building on a south or west elevation.
Fortwell whole-unit U-factors run from 0.28 to 0.54 depending on system and glazing, with SHGC from 0.20 to 0.58.
Choosing glass by elevation
North glazing can take a high-SHGC unit and gain free light. West glazing at the end of a Florida afternoon should not. Specifying two different glass packages on the same house is normal and does not change the frame, the finish or the sightline.
