Windows for best energy efficiency
Aluminium windows are as energy efficient as windows using other materials.
When choosing a window, most people only care about thermal insulation. This is indicated by U-value, or Uw. It is the requirement to be fulfilled, given by local regulations, and thanks to the addition of polyamide thermal break inside the frame, aluminium windows have similar performance to plastic or wooden windows.
But keep in mind that a window is a source of solar gain and light. You should therefore also pay attention to two other characteristics of the window: Sw (solar factor) and Tlw (light transmittance).
These values range between 0 and 1, and the higher they are, the more heating and lighting savings you will get. These values are usually very good for aluminium windows since frame profiles are very slim.
Optimize the effects of window placement
You should also think about window placement. Choosing where to place your window in the wall should not be based only on emotional reasons.
Taking into consideration the following points will bring you the best benefit:
- It is crucial to avoid thermal bridging at the junction between window and wall, or conductive pass-throughs between outside and inside
- The window has to be fitted securely and efficiently to prevent any displacement or subsidence overtime and a possible disorder
- The window needs to be properly manufactured and the opening frames correctly adjusted – the window must operate smoothly and no air leakage should be noticeable when the window is closed
- Create a weathertight seal between the frame and the wall
A professional metal builder will check that the detail construction of the wall can ensure good ventilation and drainage around the windows.
And don’t forget that, for health reasons, air renewal of inhabited spaces is mandatory. For convenience, ventilation systems are often integrated into windows and the choice of an appropriate device makes it possible to avoid any discomfort with the use.