"KARO EKO” PASSIVE WINDOWS - Uw<0.8 (heat transfer coefficient for the whole window), subframe thickness 92 mm (4-layer laminate), at the price of OPTIMA68 windows (before discount) - Uw<1.3, subframe thickness 68 mm (3-layer laminate), when a set of windows for a single-family house (at least 12 single windows)... More at KARO.