The present paper addresses experiences with infiltration and ventilation in the Active House concept, based on the Active House Specification and realized Active Houses. The Active House Specification is based on a holistic view on buildings including Comfort, Energy and Environment. It uses functional requirements to indoor air quality and thermal comfort, and does not have component requirements to airtightness or specific ventilation solutions. Experiences from realised Active House projects show that better airtightness than nationally required has been achieved. Indoor air quality is generally good, independently of the type of ventilation system installed (mechanical, natural and hybrid have been used). Good thermal comfort can be achieved in houses with generous daylight conditions. To succeed, natural ventilation and dynamic solar shading (ventilative cooling) must be applied and controlled to avoid overheating, which is possible under European climate conditions, where humidity is not a main issue during summer. The identified issues for quality and compliance have been that the current methods in standards and legislation that are used to determine the performance of ventilative cooling need to be further strengthened. And that affordable, intuitive and simple control systems for residential hybrid ventilation and dynamic solar shading are needed.