A quantitative infrared thermography method for the assessment of windows thermal transmittance

The window is one of the weakest elements of buildings envelope and it is characterized by threedimensional heat exchange that makes its study, in terms of overall thermal performance, quite complex. The thermal field on window surface is defined by different parts such as transparent zone (glass) and frame (wood, aluminum or PVC) and their matching generates thermal bridges, downgrading the insulation properties of the entire window. The hot box test is a laboratory setup which allows the evaluation of the window thermal transmittance;the paper shows the comparison between the results obtained by hot box measurements and the thermal transmittance assessed by an original experimental methodology based on quantitative infrared thermography, conducted on a wooden window.