A novel nozzle pulse pressurisation technique for determining the adventitious leakage of buildings at low pressure is investigated. The investigation is based on the ‘quasi-steady pulse’ concept and aims to explore a technique to generate the pulse by use of a compressor nozzle. The mass flow rate from the nozzle is obtained by measuring the transient pressure in the air receiver of the compressor. The technique minimizes the effects of wind and buoyancy force and has proven to be very repeatable. Comparison between the results of nozzle tests and those of piston tests indicates that the present technique is reliable for determining building leakage at low pressure. Also, the present technique is of great convenience in practical applications. It employs a very compact and portable test rig, needs only a few seconds for a test run, needs not to penetrate the building envelope and therefore can establish the leakage of a building very quickly and efficiently.