The airtightness or the permissible air permeability can currently only be determined as a total parameter for the entire building using a Blower-Door measurement or for the individual component, e.g. a window on the test stand. The aim of the project is to develop a measuring methodology and the prototype of a measuring probe, by means of which individual local leaks can be measured on the test stand, e.g. in the course of the product development of wall-ceiling connections, as well as for quality assurance with a mobile measuring probe on the construction site. These detailed measurements should form the basis for optimised component solutions and contribute to avoiding defects.