The thermally induced deflection of bimaterial cantilevers was theoretically examined, and an optimal excitation configuration was determined. The optimal heat spot position, resulting in the maximal deflection, was observed at a central location at a 0.5-0.6 length for short cantilevers and it shifted backwards to the clamped position at 0.4 length for long cantilevers. The calculated values and recent experimental results are in good agreement. The study also indirectly confirms the high value of the convection coefficient for liquid on vibrating surfaces in another experiment. These results can help to determine an optimal detection configuration for chemical and biosensing applications.