In a hotel building there are many processes which consume energy, such as lightning and drive fan motor in the ventilation system. These processes needs supplied with electricity. The building is a big consumer of heat. The heating system is supplied with heat pumps and oil. The consumption of electricity is about 1700 MWh and 350 MWh of oil. This thesis affects an energy saving investigation for a hotel and the purpose is to find measures to reduce the energy consumption for this building. The method for the investigation consisted of three steps. First step was to establish how much energy the building consumes today. Second step was to find measures which could be implemented and the third was to calculate the energy saving potential for each measure. If all investigated measures will be implemented the Hotel could save up to 40 % energy. If only the economical and easy measures would be implemented the hotel could save 30 % energy. The easiest measure was to change some parameters in the control system so the oil burners did not go at all times. With that change and a change in the control system for ventilation to reduce the hours the ventilation are on gave reduced energy consumption with 20 %. The economical investments were converting one of the oil burners to an extra heat pump and to change all old lighting to a new LED-Lighting.