The problemSurprisingly little seems to be known about the indoor air quality and temperature performance of Australian homes. There are any number of questions for which we seem to have little or no data, for example: Are we getting adequate air ventilation in our homes, and how is that affected by sealing up gaps? How often is the temperature inside our homes falling outside both (a) comfortable and (b) healthy limits?
Passive Houses need to be highly insulated. They then need to be airtight, partly to ensure there is no risk of condensation in the insulated building fabric. And then they need mechanical ventilation to ensure there is sufficient fresh indoor air for comfort and occupant health. There are several criteria within the Passive House Planning Package that stipulate the volume of fresh air the ventilation system needs to provide.