Moreover, demand response (DR) program has been implemented in order to serve the power and heat demands of the consumer with minimum cost. In the proposed DR program, the total power and heat demand of consumer will be supplied without any curtailed load. The responsive load can vary in different time intervals. In addition, it is assumed that the consumer will pay (receive) for increased (reduced) consumption, which is proportional to the day-ahead market price. In this paper, the heat-power dual dependency characteristic in different types of combined heat and power (CHP) units is taken into account and all technical constraints of generation units are satisfied. In addition, a heat buffer tank with the ability of heat storage is incorporated in the proposed framework. The verification of the proposed method is demonstrated using the simulation of a case study.