Abstract: A tube-to-tube heat exchanger for use in an air conditioning system of a motor vehicle has a unitary tube, which is internally longitudinally divided into a first passage and a second passage by a heat conductive primary web. One warm fluid line is directly connected to each end of the first passage, without the need for a separate connector. One cold fluid return line is directly connected to each end of the second passage, without the need for a separate connector. The fluid lines are connected to the heat exchanger by brazing. In one embodiment, the web is substantially planar and the cross-section of each of the first passage and the second passage is substantially D-shaped. The heat exchanger may further include a support web, extending perpendicularly from approximately mid-way along the primary web. In another embodiment, the cross-sections of the first and second passages may be substantially circular, with the primary web being shaped accordingly.