This study presents the results of an energy audit which was carried out on a sample of 35 hotels in the Prefecture of Attica, Hellas focusing on their environmental and energy performance. During the energy audit, data was gathered with the collaboration of Athens Hotel Association and the Hellenic Chamber of Hotels. Energy normalization techniques are applied for the analysis of the data and the hotels are classified using a multivariate analysis. The energy classification of the hotels in Attica in 3 classes is based on clustering techniques using the collected data on the heating, cooling and electricity consumption of the hotels in the sample. A component/factor F1 is identified, which is an index of the hotels energy saving potential in absolute value. The study stresses the importance of this factor F1 as a means to promote sustainability and energy efficiency in the hotel sector and analyzes the best case scenario of each class in an effort to study best practices, set goals and define potentials for energy conservation. (C) 2015 Elsevier B.V. All rights reserved.