For OTB GmbH, a medical supply company operating nationwide with its headquarters in Berlin, watts conducted an energy audit in accordance with DIN EN 16247–1 using a multi-site approach. The focus was on analyzing energy consumption for electricity, heat, and the vehicle fleet; conducting on-site assessments of representative locations; and identifying cost-effective efficiency measures. This resulted in a prioritized implementation plan with measures for heating and ventilation optimization, conversion to LED lighting, improvement of the metering structure, and the introduction of a standardized consumption monitoring system.