Please click the link below for the Guidelines for domestic ventilation, including MVHR/ HRV systems in Scotland:
The design guidelines leave room for alternative guidelines, such as the Passivhaus Design Guidelines for MVHR systems. These are more refined and time proven, e.g. the ventilation requirement is not based on a volumetric approach only, but also based on supply demand and on a room by room usage analysis. The ventilation requirements for a small dwellings may exceed 0.5 air exchanges by far, e.g. for flats or social housing. On the other hand large dwellings with 0.5 air exchanges, especially when occupied by few people, will often be over-ventilated and lead to too dry air in winter, which is detrimental for the health of the occupants. We therefore do not advocate a volumetric only approach in determining the normal ventilation rate.