New plastic windows VEKA - frame widths

The VEKA profiles are solid, whether SL76 or another series. Differences lie more in insulation, appearance, and installation depth. With the frame width, appearance and light loss are especially decisive. With 81 mm outer frame + 84 mm sash, you visibly lose more glass area than with the narrower variant but usually get simpler glazing beads and a more stable construction. 71 mm outer frame + 74 mm sash come closer in appearance to your old wooden windows but require precise detail work on the interior glazing beads. The combination of 81 mm outer frame + 74 mm sash is technically no problem but depends on profile compatibility. The window manufacturer has to check that. In the end, it is a compromise between appearance (narrow profiles) and installation security or stability (wider profiles).