A comprehensive experimental investigation of the performance enhancement of cooling-dehumidifying helical coils using strips fins was conducted. Finned and un-finned coils (base case) were tested at wide ranges of air flow rates, temperatures and humidity at vertical and horizontal orientations. The results showed that (i) for all coil orientations and operating conditions, the finned coil always has better performance (dehumidifying capacity, heat transfer rate, heat transfer coefficient and coil effectiveness) compared to the un-finned coils (ii) placing the coil (finned or un-finned coils) at vertical orientation enhances the coil cooling and humidification capacities, (iii) for the finned and un-finned coils at all orientations, the cooling and humidification capacities increases with increasing the air flow rate, humidity and temperature, (iv) the percentage of increase in the coil performance due to using fins or due to placing it at vertical orientations increases with increasing air flow rate and temperature and (v) the effect of using strip fins on the coil surface is more dominant in case of coil horizontal orientation. Finally the results concluded the recommendation of using finned helical coils at the vertical orientation to maximize cooling and dehumidification capacities and coil effectiveness.