The building sector has a direct impact on the environment and to humans through the use of raw materials, the consumption of natural resources and the production of pollutants and household waste. The hotels are a special category of buildings, not only of the seasonality in their often function, but also because much of the energy consumption associated with functions that are not in standard use building but relating to the provision of additional services to their customers including a spa, restaurants, pools, etc. These functions are inextricably linked with the comfort and expectations of their customers and therefore important for the competitiveness and sustainability. Data from Spanish hotels show that energy consumption for additional services such as a spa can be up to 35% of total energy consumption.

Solution to the problem is the energy upgrade, which means reducing the energy needs of the building that offers multiple benefits for the environment but also for the owners following a number of simple and effective interventions.

This research work deals with the energy upgrade of the El Greco Hotel shell building in Heraklion, Crete. The study is divided into four parts by attempting through research presentation proposal for reduction of energy consumption of the building.

The first part presents the current situation regarding the problems of environmental pollution, the building stock of our country, the energy consumption of buildings, and describes the legislative framework for energy savings in the building sector.

The second part refers to the energy consumption of the hotel facilities, the action of the European Committee for Buildings nearly Zero Energy Consumption and shows some examples of hotels that apply some principles of bioclimatic design.

The third part presents the process of energy upgrading of buildings and analyze proposals for intervention in the shell and the equipment.

The fourth part consists of the energy study of El Greco Hotel in Heraklion, Crete, recording its characteristics and the results of the energy study and then the intervention proposals in insulation, windows and shading system.