Energy Efficiency of hotel buildings includes changes in lighting, which includes the installation of LED lamps for the decrease of the power consumption, installation of central heat pumps for heating and air conditioning in order to decrease thermal losses. Also changing of door and windows frames along with hot water system, may take place in order for the hotel to be Energy Efficient and get an Energy Class upgrade. Diagnosis Multisystems has issued and developed Energy Efficiency studies for hotels of the order of 25,000 m2.