The indoor environmental quality in an operating room (OR) affects not only the patient health but also the well-being of the surgical staff. The main requirement in the OR is to reduce the risk of surgical site infection. To reduce this risk, the indoor air quality must be controlled, which requires technical standards on heating, ventilation and air conditioning (HVAC). Although the technical standards state thermal comfort must be achieved, significant discrepancies between these standards and the thermal comfort standard exist. To evaluate the thermal comfort, we have analyzed these discrepancies and we have performed a survey in 4 major Belgian hospitals. This paper summarizes the technical standards and compares them to the thermal comfort standard and to data gathered on site. Significant discrepancies between the HVAC standards and thermal comfort standard are indicated. The survey shows a similarity between the comfort standard and the actual situation in an OR. The current technical standards cannot lead to acceptable thermal conditions for all members of the surgical team due to their different needs to achieve thermal comfort. The study of such discrepancies can serve as useful input to revise the current HVAC standards and the design of ventilation and luminaire systems.