Unlike field agriculture, which bases production costs on hectares, greenhouse costs are calculated on a per square meter of growing area or on a per plant basis. The production costs represent around 78 % of the total chain costs in greenhouses, being energy consumption the main factor affecting those expenses. It is estimated that greenhouses cover an area of about 41000 ha in the European Union, setting Europe as the biggest supplier of greenhouse products in the world. At the same time, as Eastern European markets open up, the EU is also becoming the biggest consumer of greenhouse products in the world. However good the situation may seem the competitiveness of European growers is threatened by the increasingly higher costs of fuel and the competition of external growers producing at low costs. A reduction in the production costs of commodities, will help the European greenhouse producers to retain their position in the European market where internal transportation costs are significantly lower than those of external competitors. The most important aspect of the production that can be improved to reduce costs is energy consumption. Therefore, an optimisation of the energy consuming systems and operating procedures in existing greenhouses will reduce production costs enabling European greenhouse growers to remain competitive in the European market. On the other hand, reducing the energy consumption in their facilities will help farmers face the increasingly restrictive environmental regulations affecting the sector. In this project, it is intended to investigate the greenhouse energy requirements for different areas in Europe. A tool for auditing energy efficiency in greenhouses, a set of technical improvement measures and a guideline for the optimisation of energy consumption in European greenhouses will be developed and tested in several case studies taking into account current and upcoming European environmental legislation.