In this study, monthly energy consumption in a sample hospital building was calculated and compared with the actual energy consumption values of a similar hospital. In the study, the DIN and Turkish standards, especially the ASHRAE standards on hospital installation systems, were given as a summary. A sample hospital building was designed to consist of a total area of 96.000 m², with a capacity of 351 beds and 12 operating rooms, 72.000 m² conditioned and 24.000 m² unconditioned spaces. The sample building, which was designed as a rectangular prism with 12 floors, each floor measuring 100x80 m, was modeled in three dimensions using the drawing program. Types of building elements were defined in accordance with the thermal insulation calculation, and openings such as windows and exterior doors were also dimensioned. The building was divided into 14 conditioned zones according to their functions; the occupancy schedule, the devices with their power, and the working schedules were identified in the system. For the capacity calculation, the heating and cooling loads of the sample hospital were calculated in kW; the monthly energy consumption of the building was calculated in kWh/month. As a result, the energy consumption values of the sample hospital for natural gas and electricity were determined monthly and annually and compared with a similar hospital.