Proper stabilisation is one important requirement for the measurement of harmonic emission of electrical appliances. A set of modern household appliances is used to study the change of their electrical and thermal parameters after connection to the power source and the time for their entire stabilisation in a laboratory setup. Based on a novel approach, which is more robust and less time-consuming compared to other approaches, the stabilisation process for different types of appliances is determined. The impact of different test conditions, like the mounting orientation or ambient temperature on the stabilisation time is studied. The results suggest that the stabilisation times should be individually determined for a tested device and the applied test conditions has to be carefully selected to adequately reflect reality.