This European Standard sets out criteria to assess the performance of residential ventilation systems (for new, existing and refurbished buildings) which serve single family, multi family and apartment type dwellings throughout the year. This European Standard specifies ways to determine performance criteria to be used for design levels in regulations and/or standards. These criteria are meant to be applied to, in particular: - mechanically ventilated building (mechanical exhaust, mechanical supply or balanced system); - natural ventilation with stack effect for passive ducts; - hybrid system switching between mechanical and natural modes; - windows opening by manual operation for airing or summer comfort issues. This European Standard considers aspects of hygiene and indoor air quality. Health risk from exposure to tobacco smoke is excluded from this European Standard.