The overall condensing power at condensers is affected by many factors. A condensate film on the pipe wall plays a crucial role in heat transfer. The velocity of the gas phase inside the tubes has a fundamental influence on the movement of the liquid film and the specific course of the velocity profile in the condensate film. The magnitude of the shear stress at the steam-condensate interface affects the film thickness and its integrity. This paper presents a study to evaluate the effect of the flow velocity inside a vertical pipe on the heat transfer coefficient during water vapour condensation. Specifically, steam flow on heat transfer for two different pipes is evaluated, namely with inner diameters 16 and 26 mm.