Introduction (and aim) – Carbon dioxide emissions have large consequences for nature and humans. If carbon dioxide emissions continue at this rate and the average temperature increases, the tipping point will be reached, and the damage will be too great to repair. Awareness of the climate began to emerge in the late 1980s. As the years went by, awareness increased and protocols for how to stop carbon dioxide emissions was created. In 1997 came the Coyote Protocol and in 2015 came the Paris Agreement. In 2017 Sweden adopted a climate policy framework that has the goal of having net zero emissions by 2045. The goal of this study was to identify what affects carbon dioxide emissions in the construction production phase, how these contribute to carbon dioxide emissions, and how building technology solutions affect carbon dioxide emissions in apartment building projects. Delimitations have been made from earthworks, internal installations and the study relates to the building production stage, A4 and A5. The outline of work is introduction, theoretical framework, method and implementation, results, discussion, conclusions, and suggestions for further research.

Method – The research method was a case study with a multiple case design. Data collection methods were a document study of the data provided to the group by Skanska Sverige AB as well as a literature study of doctoral dissertations, handbooks, articles in scientific journals, research reports and conference contributions. A intervju was conducted to complement the document study.

Results – Skeppsbron 2 emitted 306.9 kgCO2eq/m2 during A1-A5 construction phase, of which module A4 transportation accounted for 13.9 kgCO2eq/m2 and A5 production for 31.8 kgCO2eq/m2.Slåttertiden had a lower climate footprint and emitted 290.7 kgCO2eq/m2 during the construction phase, where A4 accounted for 16.3 kgCO2eq/m2 and A5 for 44.7 kgCO2eq/m2.

Analysis – The construction production phase contributes 9–21% of the carbon dioxide emissions during the construction phase. The construction phase accounts for 25–70% of carbon dioxide emissions during the entire life cycle. What differs the most regarding the building technology solution is the carbon dioxide emissions in module A5.1. Carbon dioxide emissions in module A4 are not affected by the building technology solution but depend on the transport distance.

Discussion – When comparing projects, the uncertainty is great, which means that the result can only give an indication of the carbon dioxide emissions.