The total losses through the windows amount to 50% of the heat losses of the building, they are usually ten times higher than those through the walls, so it is clear how important the energy efficiency of the opening is in the total energy requirements of the building.
Special attention needs to be addressed to the following:
- Multilayered glazing,
- Instead of air as an insulator, the space between the panes can be filled with inert argon gas, which increases the efficiency of the window,
- Low-e coating which prevents loss of heat,
- Heat losses occur both through the glass and through the window frame,
- Total heat transfer coefficient Uw <1.4 W / m2K.