The performance of the triangular finned vertical helical coil heat exchanger experimentally and mathematically was investigated. Hot water flows inside the helical tube at 60 ᵒC while cold water enters the shell at 30 ᵒC counter currently. A triangle copper fin with 1 cm height, 2 cm base length, and 0.3 cm thickness at 4 cm pitch distance was welded at the external surface of the helical copper coil tube. Along the coiled tube123 fins were welded on the outside surface of the helical coil tube heat exchanger. The results showed a good enhancement ratio compared to the unfinned one. The heat enhancement was 12 % with effectiveness 11 %. The improvement in the Nusselt number was 16.5 %. These results confirm that the added fins to the helical coil heat exchanger modified and improve the helical heat exchanger which is suitable for the industrial design with better performance.