Design of the first net-zero energy buildings in Estonia

In Estonia, comprehensive regulation establishes the methods for calculating the indoor climate and energy performance of buildings to prove their compliance with minimum requirements. The definition of a nearly zero-energy building and a net-zero energy building, and the methodology for the calculation of the energy performance of the buildings in Estonia are explained. The problems and results of the design process of the first zero-energy building in Estonia are described through a case study. The current study showed that it is possible to reach zero-energy building levels in Estonia by careful and detailed designs of the energy performance of a building. More thorough analyses are needed in the very first stage of the design to find suitable solutions and possible compromises between architecture and energy efficiency. In any case, well-insulated buildings, effective building service systems, and local electricity production on-site is needed for zero-energy building. Finally this article discusses the problems and limitations of the regulations influencing the motivation and actions needed to achieve zero-energy buildings. The study shows the influence of the different parts of the building on the balance of the energy consumption and utilization, and on the energy performance of the building to achieve zero-energy building status.