Air infiltration contributes to a heat loss typically representing up to one third of the heating demand of a building. The building airtightness, also quantified as air leakage, is the fundamental building property that impacts infiltration. The steady (de)pressurization method (blower door) is the widely accepted standard process for measuring building air leakage. However, this method requires the enclosure to be pressurised to a typical range of 10-60 Pa, which is not physically representative of the pressures experienced by buildings under natural conditions. The Pulse technique is a novel alternative method, which measures air leakage at low pressures; quoting it at a reference pressure of 4 Pa. An experiment was designed to test the leakage characteristics of a detached house in the UK and compare them with the infiltration rate; which were measured by tracer gas techniques, utilising the decay method. The blower door and Pulse tests were both performed multiple times during a six week period to cover a range of different environmental conditions. Initial results have shown that there might be correlation between the infiltration rate and air leakage at 4 Pa and 50 Pa. It was concluded that Pulse technique’s results induce less uncertainty when predicting air infiltration. Further experimental testing is required to be carried out in a range of properties to investigate how this conclusion stands and how the results given by existing infiltration models compare with the experimentally obtained infiltration rate.