Glazing performance
The glazing package is a specification, not a default
Two windows on the same frame platform can be a long way apart on energy performance. NEXWD publishes certified U-factor and SHGC per line and per glazing package rather than quoting one number for a whole catalogue.
Double to triple, without changing the frame
On the Wood-Clad Tilt & Turn, moving from double to triple glazing takes the certified U-factor from 0.25 to 0.18. No frame change, and no surcharge beyond the glass itself. Not every line carries the option — ask which ones do for your climate zone.
West-facing exposure is a different problem
Afternoon sun through an ordinary low-E unit still drives cooling load and fades interiors. The frame and the glazing package both have to be specified for the exposure, not only for the view.
Laminated glazing on impact-rated systems
Impact units are two tempered lites bonded to a PVB or SGP laminated interlayer. The glass is expected to crack under a large-missile strike. What it is not allowed to do is leave the frame — structural adhesive ties the interlayer into a reinforced frame, and that bond is the detail an inspector looks for.
Getting a number you can put in a submittal
Send the opening, the orientation and the code you are meeting. We confirm the certified configuration in writing with the quotation, and the ratings can be looked up independently in the NFRC directory.