How much passive ventilation is required?
Following extensive research in the UK a minimum requirement for background passive ventilation (also known as trickle ventilation) has been adopted. This minimum requirement is for 4000mm2 minimum air opening per average sized room that is used for normal living activities. This does not include bathrooms, laundries or kitchens. These may require more ventilation in the absence of other methods of moisture extraction. This can be achieved by a minimum vent length of 600 mm. The above recommendation is the same as that recommended by BRANZ.
