For contemporary, new buildings in contexts like Sweden, life cycle assessments clearly display that embodied carbon often represent more than half of the emissions seen over the life cycle. While policies for many years have targeted operational emissions, limited focus has been on buildings´ embodied carbon. To abate sectoral greenhouse gas emissions, policies for mandatory climate declarations or even limit values for embodied carbon are being introduced. In the Swedish case, a regulation on mandatory climate declarations is in effect from 2022, and limit values are likely to be introduced in the coming years. The need for consistent knowledge on the embodied carbon of contemporary building construction as well as the potential of various mitigation strategies, is therefore critical to step up emissions reductions in the sector. This study aimed at developing robust reference values for embodied carbon, representative for the contemporary new construction in Sweden. Based on assessments of nearly 70 new Swedish building cases, reference values were developed for central building types. The results display a high variation within each building type, thus showcasing considerable emission reduction potentials with available technologies. The study embraces many analyses, among others on the potential effects of various properties of the sampled buildings, such as noise requirements, energy standards and analyses of improvement potentials through greener product supply. The study provides a profound basis for the further development of limit values in for example procurement processes and in regulation for the Swedish context. In an academic perspective the study is unique through the representative building sample, consistent assessment methodology applied for all cases as well as displaying insights into details of the variations of embodied carbon in contemporary construction.

Denna rapport beskriver resultatet av den uppdragsforskning som genomförts åt Boverket inomramen för Boverkets och Upphandlingsmyndighetens regeringsuppdrag ”Uppdrag att främja minskadklimatpåverkan vid offentlig upphandling av bygg-, anläggnings- och fastighetsentreprenader”, för attta fram referensvärden för klimatpåverkan för nya byggnader. Baserat på analyser av närmare 70byggnaders klimatpåverkan för byggskedet (modul A1-A5) har referensvärden för klimatpåverkantagits fram för flerbostadshus, kontor, förskolor, skolor och småhus. Resultaten visar generellt på enstor spridning inom byggnadstyperna, men ger en god grund för att kunna gå vidare med utveckling avolika typer av gränsvärden i till exempel upphandling eller utveckling av regelverket förklimatdeklarationer. 

Decision support tools for incentivizing environmentally sound decisions in building design,such as LCA (life cycle assessment), have been highlighted as an essential feature for enhancingthe realization of more sustainable buildings. Nevertheless, the use of LCA to support decisions inbuilding design is still limited in practice. A better understanding of the social dynamics and detailedcontexts of the decisions leading up to a final building design is therefore critical for better integrationof LCA-based information in the decision-making processes. This paper reports a qualitative, semistructuredinterview study of single-family home producers in Sweden and their decision-making inrelation to climate mitigation, with a particular focus on embodied carbon mitigation. By studying aspecific branch of the building and construction sector, a more in-depth record can be obtained of theparticularities of implementation contexts and decision-making situations in which LCA may, or maynot, have a role in driving climate mitigation. Four primary decision contexts in which LCA mayhave an influential role to drive embodied carbon reduction include: (1) the development of buildingsystems, (2) development and offering of house models, (3) the selection of construction products forthe building system as well as for the offer of add-on products to customers, and (4) the dialoguesin the individual house-buyer projects. Decision-making that affects sustainable outcomes in thispart of the sector is very much dependent on a supporting regulatory context. Over the years, usingbuilding LCA in early design stages, for optimization towards low-impact final buildings, has been arepeatedly promoted recommendation both in academia and practice. This study, however, revealsthat such a conclusion is too simplistic. The different overarching decision contexts identified for thisparticular branch display the variety of needs for life cycle-based information.