Heat exchangers consisting of finned tubes are commonly employed in air conditioning systems. which are used at low Reynolds number because of the needs of low noise, saving energy, etc. The effect of the construction of the heat exchanger on the heat transfer and friction characteristics was reported in the former reports. In the present work, the row by row performance of single-and multi-row tube and plate fin heat exchangers was evaluated. Their performance is dominated by three regions : a developing flow region for the first row, a transition region for the second row and a vortex region for the downstream row from the third row. For each region, dimensionless equations on the performance were obtained and a generalized correlation was obtained.