Abstract: Disclosed is a penetration fitting unit for seal-connection between a wall and a pipe passing through a wall opening. The unit has a cylindrical sleeve having inlet and outlet ends which internally define a tubular passage. Between the inlet and outlet ends there is at least one limit stop element protruding outwardly from the outer surface of the cylindrical sleeve having a locking ring that can be coupled with the cylindrical sleeve at the outlet end thereby forming a seat for the wall. A heat transfer means is interposed between the limit stop element and the sleeve outlet end. The heat transfer means is placed at a portion of the cylindrical sleeve's outer surface and has a first area at least partially overlapping with respect to the seat for the wall and a second area overlapping with a portion of internal surface of the locking ring.