The impact of wind gusts on air infiltration in buildings

Air infiltration holds a central role in building energy consumption and is associated to several building physics phenomena. Air infiltration in buildings due to wind-induced pressure is a complex process, strongly influenced by the turbulent nature of wind. This extended summary highlights the findings of a series of studies with focus on unsteady wind and its impact on air exchangesin buildings. The focus is on wind gustiness and its relation to air infiltration under natural conditions. Wind spectrum analysis shows that high-frequency wind gusts provide important information, while only considering mean wind speed and direction are not adequate to predict air exchanges in buildings. The impact of gustiness becomes greater for evenly distributed leakages between windward (upstream) and leeward (downstream) façade. Infiltration measurements under unsteady wind can vary significantly from results estimated based on pressurization measurements. In addition, wind gustiness is responsible for large pressure differences across leakages, thus it can affect the results of leakage numbers and the uncertainty of such measurements especially when the measurement point is low.