Everyone has to take a greater responsibility in energy issues, both individuals and companies. There have been some major developments in the construction industry but there is still a lot to be done.   This diploma work thesis presents different methods of making existing construction shed establishments to use less energy. What is possible to do and how much energy is there to be saved? A shed establishment consisting of 8 shed units were studied in this project and the building simulation tool VIP-Energy was used to simulate different types of material in the sheds. An infrared camera was used to locate thermal bridges.   There are several factors that can be improved to make a construction shed establishment to use less energy. Replacement of old windows and doors, using more insulation, replacement of old less efficient insulation with new improved materials, using a different heating system, and more. One factor, which is more important than all the others, is to insulate between the 8 different shed units in the establishment. It is also important to make the construction wind proof.   The results show that if you replace the old wall and roof insulation with new better insulation, replace the old windows and doors and seal the gaps between the shed units the total energy reduction would be as high as 60%. All companies working with the handling or utilization of shed establishments at building sites should consider these improvements.