Ductwork airtightness is an input parameter in the French energy performance calculation method for new buildings (RT 2012) which influences the energy performance rating. If the ductwork airtightness class used in the calculation is better than the default value (2.5*class A), the ductwork airtightness has to be justified in accordance with a third-party testing scheme operational since 2014. Furthermore, there is a minimum ductwork airtightness requirement set to leakage class A if the building applies for the Effinergie+ or BEPOS labels. Field data collected through the testing scheme suggest that awareness is slowly growing as the leakage class distribution has shifted towards tighter systems compared to previous data.
