This document is the abstract of a paper that was submitted at 2010 AIVC Conference, in Seoul, South Korea. It analyses the energy impact of envelope and ductwork leakage estimated with the regulatory calculation method for different building and ventilation system types, in the context of the revision of the energy performance regulation scheduled to be gradually in force between 2011 and 2013 depending on building types. The objective is to generalize low-energy buildings whose market share is increasing rapidly with the current regulatory label named BBC-Effinergie. Given that envelope and ductwork airtightness are key in these types of buildings, significant efforts are made to better take into account these issues in the calculation methods as well as to define schemes to encourage better airtightness. These include the tuning of the default values and minimum requirements as well as quality management approaches or craftsmen and measurement technicians certification.