When creating the SL 38 window system, attention was paid to the comfort of the home. Thermal performance and air tightness are key points for a balanced indoor climate.

The new SL 38 offers a three-level thermal seal, providing a living space where airflows do not penetrate. The increased depth of the system easily leads to UW values of 1.4 W / m²K, similar to high-quality window systems, such as the CS 86-HI.