This important certification takes into consideration three areas for evaluation. The category Nature’ considers performance in terms of the energy efficiency of the building envelope and building services, as well as the use of resources linked to the design and management of the hotel structure. The category ‘Life’ assesses the way the hotel considers the wellbeing of the guests. A further criteria, ‘Authenticity’ evaluates the respect of the construction to traditions and use of materials. Finally the category ‘Transparency’ analyses the costs of construction and management, quality of service offer and capacity of communication of the values of eco-sustainability.