The annual worth for production of heat and power of an endoreversible Carnot engine is analyzed by using the methods of finite time thermodynamics. It was found that, in order to obtain the maximum annual worth of production of heat and power,in the design of such systems, the heat exchangers on the hot and cold sides of the Carnot engine must have equal products of their size and heat transfer coefficient. Also, for the maximum annual worth, the ratio of the lower and higher temperatures of the Carnot engine should have its optimal value.