A heat exchanger and method for defrosting a heat exchanger is disclosed and which includes a heat exchanger having a fluid receiving conduit, and at least one space which is defined, at least in part, by the fluid receiving conduit, an expandable and contractible heating element which is received within the space, and which is located in heat transmitting relation relative to the fluid receiving conduit, and a biasing member mounted on the heat exchanger and the heating element and which longitudinally, and resiliently restrains the movement of the heating element relative to the heat exchanger during the expansion and contraction of the heating element relative to the heat exchanger.