There is disclosed a heat exchanger extending along a longitudinal axis, including a first conduit configured for circulating a first fluid; a second conduit configured for circulating a second fluid; and a heat transferring layer disposed between the first conduit and the second conduit. The heat transferring layer is monolithic with the second conduit. An abutting side of the heat transferring layer is in contact with the first conduit to define a surface contact interface therebetween. The abutting side is shaped to correspond to a shape of a surface of the first conduit in contact with the heat transferring layer. A thermal resistance defined between the second conduit and the heat transferring layer being less than that across the surface contact interface. The first conduit is in heat exchange relationship with the second conduit via the heat transferring layer.