Heat exchangers have its major application in automobile, air condition, refrigerator, power plants, and many others. Heat transfer characteristics and performance of Copper spiral heat exchanger are investigated and compared with pure water. Nanofluid can enhance thermos-physical properties. Experiment is carried out for water based SiO2 Nanofluid with 15 nm average sized nanoparticle at varying air velocity and mass flow rate of fluid to investigate its effect on heat transfer coefficient. From the experimental data, a closed form solution for Nusselt number has been calculated using ∈-NTU method. A new correlation has been proposed as a function of Reynolds number and Prandtl number. The heat transfer rate, effectiveness, has been significantly higher compared to pure water and with increasing volume fraction of nanoparticles.