DEUMESS e.V. is an alliance of independent medium-sized and regionally operating companies that record energy data in residential and commercial properties and make them usable for owners and tenants. The energy data recorded can be used to sink and control energy consumption, optimise the building services, and integrate regenerative energy sources into the energy system. DEUMESS members are therefore directly involved in making the energy transition succeed in buildings. More than 3.5 million homes receive services from member companies of DEUMESS.