Dr Kara Rosemeier
Passive House Academy New Zealand
Ventilation and air tightness: chicken and egg?
Rosemeier will spell out why airtightness should be viewed as a supporting factor in our quest for good indoor air quality, rather than a reason to worry. She will review research results that show air leaks as non-contributors to indoor air quality goals, and outline the reasons why, regardless of the blower door test results, purposeful ventilation persists as a design task.
Air-leaky buildings are not healthy places to dwell for reasons unrelated to fresh air needs: they are less comfortable, noisier and more prone to mould formation at surfaces and in cavities.
When we increase the airtightness of the building envelope, we are addressing the indoor environmental quality issues associated with air-leaky buildings while improving the chances of survival in case of a fire (because an uninterrupted airtightness layer also reduces the risk of fire and smoke propagation.) But nothing changes for our fresh air needs. Good indoor air quality is no coincidence – we need to design for it. Rosemeier will discuss how the most reliable strategy uses a balanced mechanical system with heat recovery to constantly provide enough fresh air without annoying the people inside the enclosure.
Rosemeier is a board member of New Zealand’s Passive House Institute, leading its Passive House Academy New Zealand and teaching building science in the South Pacific. Previously, she has been the director of an engineering consultancy; advised federal and state
governments in Germany on matters of building energy efficiency; supported private clients on Passive Houses design; and supervised hundreds of retrofit projects.