An increasing number of countries (e.g. Czech Republic, Denmark, France, Germany, Ireland, Netherlands, Norway, Portugal, UK) include in their regulations either required or recommended minimum airtightness levels with or without mandatory testing. The number of tests performed on a voluntary basis is rapidly increasing either because of the energy penalty for untested buildings in the calculation method or due to the specific requirements of a given program. Furthermore, mandatory testing came gradually into force in the United Kingdom, Portugal, Denmark and France. In addition, the need for airtightness testing is also expected to grow strongly in other countries without specific airtightness requirements as the EP calculation methods typically has envelope airtightness as a parameter in the calculation procedure. Therefore, obtaining good airtightness results through testing can be an effective way to achieve the required EP levels. In this context, the development of competent tester schemes represents an opportunity for improving the reliability of the building airtightness tests including monitoring the application of policies in practice. 

The project has been running since its start in the context of the TightVent Airtightness Associations Committee (https://tightvent.eu/partners/taac), with a scope originally restricted to building airtightness but progressively broadened to ductwork airtightness issues as well.