There is provided a thermostatic working element comprising: a housing for receiving an expansion medium; an electric heating element arranged in the housing and provided with connecting lines, wherein a base of a bottom side of the housing comprises an opening for passage therethrough of the connecting lines; and a gasket disposed between the electric heating element and the base of the bottom side of the housing, essentially surrounding the opening, wherein the housing further comprises a recess located in proximity to the electric heating element, configured to press the electric heating element and the gasket against the base of the bottom side of the housing and thereby sealing of the housing is facilitated.