Window with 5- or 6-chamber system profile?

Thank you! What are the advantages of 5 versus 6 chambers? The U-value is 0.6. I really have no idea about that :( A friend also said that windows with 6 chambers become thicker and heavier and therefore the windows and fittings wear out faster?! Thanks for your help...

The U-value of the frames decreases from ~1.3 W/m²K to ~1.1 W/m²K (these values may also be somewhat different). This reduces the transmission heat loss of the component "window frame". Paired with the glass, the U-value of the entire window is obtained. By the way, I would assume that the glass makes up the lion's share of the window weight. Also, a window does not really warp, unless it has a strange geometry (e.g., 1.5 m wide in one sash).

Your 0.6 W/m²K sounds more like the Ug - the U-value of the glass.

Hello, we have just ordered our windows as well, we have an 82-profile with 6 chambers. We are building a kfw-70 house. It might be related to that. However, we place great emphasis on security, which is why we are getting safety glass everywhere and RC2 or RC3 fittings.