For the purpose of developing optimized control algorithm for room air-conditioners to ensure their energy efficiency, a short time interval (i.e., one minute) simulation of building thermal performance is necessary because the sampling time interval for room air-conditioner control is one minute in general. This paper studies the short-time interval room air temperature simulation method using the response factor method. Using the simulated room air temperature, an air-conditioner's running time can be known so that its energy consumption can be estimated accurately. In order to verify the simulation accuracy, an actual room equipped with a gas-engine heat pump (GHP) air-conditioning system is studied by both simulation and measurement. The cooling amount produced by the GHP is calculated using measured refrigerant pressure and temperature at condenser and evaporator respectively. The Root Mean Square Error (RMSE) between measured cooling amount and simulated cooling load is 18.9 percent of the average measured value. The profile of simulated room air temperature in both air-conditioned daytime and nighttime without air-conditioning can match the measured room air temperature. With respect to the estimated energy consumption, the profile of simulated energy consumption can match the measured data. The simulation accuracy of room air temperature and energy consumption during the air-conditioner start-up period is not good and needs to be improved in future research. But in general, the verification shows that this energy consumption simulation method is acceptable for evaluating the energy performance of a room air-conditioner, and can also be a useful tool for commissioning room air-conditioners
