However, a recent survey performed in the framework of the Tightvent Airtightness Association Committee (TAAC) working group showed that awareness in Europe regarding ductwork airtightness is very low [10]. In addition, recent measurements performed in France in the context of the Effinergie + label [11] have shown that almost 50% of the ductwork systems in the tested houses have a ductwork airtightness of 2.5*class A or worse.

This stresses the need to change construction habits because ductwork, in most of the tested buildings, was designed to achieve at least class A (required by the Effinergie + label) but missed the target.