Abstract: A bimetallic disc-actuated thermostatic switch comprising a switching assembly including a housing containing fixed and movable contacts and a cap and disc assembly on the switching assembly for moving the contacts between engaged and disengaged positions. The cap and disc assembly includes a bimetallic disc, a support disc for supporting the bimetallic disc on the housing, and a retainer cap for retaining the bimetallic disc on the support disc. The cap has at least one air circulation opening therethrough, and the support disc is formed so that air from the exterior of the cap can pass through the air circulation opening and across the underside of the bimetallic disc to provide increased responsiveness to ambient conditions.