The U value is the measurement of the rate of heat loss through the glazing. The lower the U value, the less heat will be needlessly escaping. The Aru 78 type windows are designed to be energy efficient – the 78 mm frame profile allows using a thicker glazing with a lower U value.

By changing one of the glasses in the standard glazing, it is possible to make the glazing more sound-proof, safe and private. Laminated glass makes the window more sound-proof. When a toughened glass breaks, the created pieces are small and have round edges that do not injure people; therefore it is advised to use it in crowded places and in big window panes.

Privacy is added by using tinted, opaque or patterned glasses. It is a very common solution for sauna and bathroom windows.

The Aru 68 window frame allows installing additional seals and SWS (plastic) spacers in order to break the cold bridge at the edge of the glazing.