Window performance

It is frequent to be interest in the glazing but much less in the closure as a whole.
But it is indispensible to be interested in the window (door, bay window ...) as a whole: frame, glazing and framework. In addition the quality of the framework assembly of the building structure is important.
 
The ability of glass preventing the loss of calories is indicated by the thermal transmittance U expressed in watts per m2Kelvin. The lower the coefficient is the more glass is insulating.
The coefficient Uw ( "w" for Windows) expresses the performance of the window as a whole.
It is also useful to look at the solar factor indicated by the letter "g" and expressed in percentage. It indicates the ability of the glazing to let in the sunlight and thus its energy contribution.
Finally it should be noted that the level of light transmission may also vary depending on the selected options.

Depending on the location, size and orientation of the openings, as well as on involved solar control solutions the choice of windows will vary. It may be appropriate to combine in one building windows with a different performance.

There exists today a wide variety of window styles and costs that we will not list. Note that the performance report is from 1 to 10 between a simple window glazing in a low quality framework (Uw = 6) and a certified Passive House window (Uw = 0.7).