Thermal fluxes transferred during HVOF thermal spray have an important influence on the thermal history of the work-piece. Thus, there is an interest in quantifying these fluxes. Today, different studies based on the use of calorimeters were proposed in the literature and CFD calculations may also be used to confirm the measures. In the present study, a new method based on the measurement of the transient increase of the work-piece temperature was used in order to estimate the thermal exchanges between an HVOF jet impinging on different diameter cylinders. The results indicate that fluxes of several MW/m2 may be transferred depending on the standoff distance, spray parameters and gun.