In the past 40 years, since the first oil crisis in the seventies, energy and climate goals have been shaping many countries´ policy and legislative agendas. The building sector plays a crucial role in achieving these goals, considering the energy use attributed to buildings and its huge potential for improved energy performance. Whereas in the past most of the focus was on reducing the energy consumption, it is not clear that better performing buildings must ensure an acceptable Indoor Environmental Quality (IEQ), by providing higher Indoor Air Quality (IAQ) and comfort levels for their occupants. Building ventilation entails both challenges and opportunities to achieve this goal. In 2019 the AIVC completes its 40th year of existence and the conference organisers thought that it would be good to pay a particular interest to the evolution during these 40 years.