Energy savings and material savings may be introduced by inte nal or external measures. Saving of energy has been promoted, e.g. by economic support, information, energy saving contracts and through energy saving companies (ESCOs). These companies offer expert consultancy including guaranteed reduction of both energy consumption and costs. The ESCOs plan and carry out investments and technical solutions in close cooperation with the customer company. The customer pays the costs of the project by savings generated by the project. This means that the customer does not need own resources to carry out an energy saving project.