Consumption level and working effect of operating HVAC systems in existing hospitals is valuable to be figured out.The investigation on operation consumption in hospitals with different HVAC systems are implemented through data research.The subjective and objective evaluations are provided for the indoor air quality and hygrothermal environment through questionnaires,field visits and field tests.The influence of HVAC system types on the energy consumption in hospitals is concluded,meanwhile,the drawbacks about the operation of HVAC systems are listed in this paper.It is found that the indoor air quality in buildings and building energy efficiency can be guaranteed by means of manual intervention,such as the improvement on professional skills of administrators,increase in intelligent auxiliary ways and enhancement of supply for fresh air in buildings.These can provide references and optimization guidance for the design of new hospitals,operation,maintenance and reconstruction of old hospitals.