A model for full-size vehicle climate chamber was established based on Matlab/Simulink to study the transient thermal performance and to improve the heating/cooling rate. The model consists of the chilled water system model, chamber air model, building envelope model, and the control system model. Finite difference approach was employed. The model has been verified by experiments conducted in the full-size vehicle climate chamber. Thermal analyses were conducted for both heating and cooling tests, and several main factors that affect energy consumption were considered. It is concluded that the heat loss through building envelope accounted for only 4%, which is much less than the heat loss caused by air tightness and improper control strategy, which accounted for more than 10% and 60%. For zero air leakage case, the average heating and cooling rates improved by 15.1% and 7.7%, respectively compared to the case with air leakage. In the end, a new control strategy was developed for the heating test based on the analysis results and this new control strategy reduced the total heating time by 27%. (C) 2014 Elsevier B.V. All rights reserved.