The number of renewable power plants has recently been increasing; hence, it is essential to maintain a balance between the supply and demand of electric power. We employ the technique of demand response (DR) through the manipulation of air conditioners. In summer, the electric demand for air conditioning consumes the majority of the available total electric power; therefore, regulating this demand compliments the requirements of peak-cut and load leveling. However, the manipulation of air conditioning impacts the user comfort and the stability of the machine. Moreover, the energy consumption of air-conditioners is uncertain owing to the operation conditions. Consequently, it is difficult to estimate the performance of the DR method. In this study, we focus on the variable refrigerant flow system, which is a popular air-conditioning system in Japan. We evaluate the performance of the demand response method using a simulation analysis and ensure that the amount of DR to regulate the air-conditioner is controlled quantitatively.