A hermetic compressor with internal thermal insulation, comprising: a compression cylinder (3) having one end closed by a valve plate (7) provided with a discharge orifice (7a) and having a front face (7c) against which is mounted a cylinder cover (5, 10) internally defining a discharge chamber (5a, 11); and a spacing duct (20) having one inlet end (21) hermetically mounted to the front face (7c) of the valve plate (7) and open to the discharge orifice (7a) and an outlet end (22) hermetically mounted to the cylinder cover (10) and open to the interior of the discharge chamber (11), said spacing duct (20) defining a hermetic fluid communication between the interior of the compression cylinder (3) and the discharge chamber (11) maintaining the cylinder cover (10) spaced from the valve plate (7) and defining, with the latter, an annular plenum around said spacing duct (20).