Nanofluid is colloidal suspension of nanosized solid particles in a liquid. Generally nanoparticles are made of metals, oxides, carbides, while base liquids may be water, ethylene glycol or oil. Having suspended tiny particles in the base liquid improves the thermal conductivity and thus the increase in heat transfer performance is expected. A test study has been completed to examine the0heat0transfer0performance of water and CuO nanoparticles. This current experiment demonstrates the increases in convective heat transfer in nanofluid. The nanofluid developed by adding CuO nano sized particles of 10-20 nm in base liquid. Demineralized water is used as base liquid. Nanofluid with different volume fraction of CuO nano sized matter between 0.025-0.5 percent used in this current work. The test setup consists of a test section that includes copper pipe of 1000 mm length, inner diameter 10mm and a heater. To minimize the heat loss in test section, insulation layer is covered. Thermocouples are utilized in test section to measure the temperatures. The effect of solid volume fraction, nanofluid flow rate and the inlet temperature on heat transfer performance of the nanofluid is examined in this current work. The results show an increment in heat transfer with raising volume0fraction of CuO nanoparticles and increase in temperature.