Reducing the energy consumption of the air-conditioning system is of significant importance for building energy conversation. Removing indoor heat and moisture by terminal device is a basic component of the air-conditioning system. In the present study characteristics of this terminal handling process are investigated from the perspective of entransy dissipation. Characteristics of indoor heat sources are firstly clarified in terms of the temperature and heat flux. Depiction of entransy dissipation and objectives of this terminal handling process are then researched. Influences of mixing processes are quantified taking both Q and T into account. There are mainly two objectives for optimizing the heat collecting process: reducing the transferred heat Q from heat sources and increasing the required temperature of cooling source Tc. Case studies are carried out based on entransy dissipation analysis. Principles for improving the performance of terminal handling process are then proposed and discussed. It's indicated that adopting THIC system and avoiding mixing processes are two main approaches for an optimized indoor terminal process. The present analysis is beneficial to construct an energy efficient indoor terminal process and realize performance optimization of the entire air-conditioning system. (C) 2016 Elsevier B.V. All rights reserved.