A furnace heat exchanger assembly includes first and second heat exchanger halves. The first heat exchanger half includes a first half of an exhaust channel and an inner joint flange half at an end thereof. The second heat exchanger half includes a second half of the exhaust channel and an outer joint flange half at an end thereof having first and second capturing tabs. The first and second heat exchanger halves are coupled together such that the first and second capturing tabs substantially overlap the inner joint flange half to form a joint flange.