The R7 sash contains 4 acrylic panes providing 3 insulating airspaces in 2.5" sash depthwith a calculated Visible Light Transmission of 72%.
The sash can be installed as fixed units, or with proper detailing and installation, as operable lift-out units. Emergency egress requirements may be met for operable windows providing a minimum 22” clear width opening and 5.7 sf minimum area. WonderWindows are designed to fit 24" o.c. framing can meet this criteria with opening heights of 40" and above.