Airtightness of commercial and institutional buildings: Blowing holes in the myth of tight buildings

It is often assumed that commercial and institutional buildings are fairly airtight and that envelope air leakage does not have a significant impact on energy consumption and indoor air quality in these buildings. Furthermore, it is also assumed that more recently constructed buildings are tighter than older buildings. The fact of the matter is that very few data are available on the airtightness of building envelopes in commercial and institutional buildings. The data that do exist show significant levels of air leakage in these buildings and do not support correlations of airtightness with building age, size, or construction. This paper presents the airtightness data that are available and the limited conclusions that can be drawn from these data.