For the past year’s climate change has been a hot topic for the world leaders and organizations, with discussions regarding how to reduce the environmental impact. The construction- and real estate sector are responsible for majority of the greenhouse emissions and other pollutants that affects the global climate. The energy consumption from operational phase has long been the main cause to the environmental impact but lately studies and research has brought increasedattention to the fact that the construction phase may have a greater significant to a building’sclimate impact.The purpose of this study is to investigate and identify the key factors and building parts that contributes the most to greenhouse emissions for the residential building during the construction phase. The results that are presented is based on life cycle analysis data (LCA) and calculated with a LCA tool called Byggsektorns miljöberäkningsverktyg (BM 1.0) from IVL.The conclusions this paper presents is that the product phase stands for most of the environmental impact during the construction phase with material as the key contributor. It shows that the choice of materials and products plays a crucial role for a buildings total impact. Transport and construction production have a minor impact compared with the product phase.