Air leaks through windows. How to prove them

 Can air leaks through windows be claimed as construction defects or building defects?  How are they measured or proven  in court?  

      To begin with, it is not an acceptable argument on the part of  the developer that this is normal and that the windows were installed in accordance with the applicable regulations. Micro-ventilation (the minimal factory-built openings in the joinery that allow ventilation to work, as required by the CTE) must not be confused  with significant air leaks occurring while the windows are closed.

                In some developments,  air leaks through the windows in the bedrooms and living room are widespread, occurring in windy conditions because these are often tall  buildings with no other high-rise buildings around them, causing noise (whistling) as the air enters and seeps inside, as well as a loss of comfort and  the resulting cost of heating or cooling the home.

In such cases the air seeps in around the perimeter of the windows and through the gap for the roller-shutter strap, and some windows also have insulation problems. This can easily be verified using a lit lighter to see how the flame moves, and a sheet of paper that likewise moves near the window, showing the air coming in (and all of this should be recorded on video).

In addition, checks were carried out using thermal imaging (with a thermal imaging camera, like the ones we use in our expert inspections, which detects cold areas and heat loss)  and an exploratory opening was made below the bedroom window of one home, revealing that the thermal insulation only reached a horizontal metal profile, leaving an area of up to 12.5 cm without thermal insulation up to the window opening; the gap had been filled with mortar, a material that does not meet the thermal requirements of an insulating material.

Please note that all of this can perfectly well be claimed if you are within the time limit. Get advice.