To mitigate environmental issues of the thermal power plants, their greenhouse gas emissions are factored into the unit commitment (UC) problem. Moreover, demand side management as an effective strategy can relieve the energy security and environmental issues. Thus, the residential customers as one of the major groups of the customers, should be incorporated in the UC and generation scheduling problems. In this study, implementation of demand response (DR) programs in the UC problem are modeled. Herein, the implemented DR programs are entitled nonlinear DR (NDR) programs because nonlinear behavioral models for the residential customers are considered. In addition, the value of cost correlated with the implementation of the NDR programs in the UC problem (UC-NDR) are modeled. It is demonstrated that cooperation of the residential customers in the UC-NDR problem can be beneficial in decreasing cost and greenhouse gas emissions of the thermal power plants. In addition, it is concluded that comprehensive studies are needed to realistically model the residential customers behavior, since the different behavioral models result in different solutions and outcomes for the UC-NDR problem. (C) 2016 Elsevier B.V. All rights reserved.