In January 2022, a new requirement will be introduced for declaration of building’s carbon footprint, which is a comprehensive requirement compared with previous regulations. This will hopefully lead the industry in the direction to achieve a net zero carbon footprint by 2050. This study explores the challenges and opportunities of this new requirement to serve as an approach to make more environmentally friendly choices. Many companies currently lack relevant knowledges to perform and evaluate building’s carbon footprint and thus may find this requirement challenging. The purpose of the study is to motivate construction companies and explore the benefits of this requirement in reducing CO2 emissions. This research work is focused on a building case which was built recently by a small construction company. The company runs by some craftsmen and it can therefore be a challenging task to understand and fulfil this requirement. In this study, a life cycle analysis is performed using the documents and materials obtained from the construction company. The declaration requirement concerns mainly the materials used in the building envelope as well as interior walls and load-bearing structures. The requirement is set on the CO2 emitted from production of building materials and components off-site along with on-site production of buildings (i.e. modules A1-A5 in a building's life cycle). The same scope is also applied in the study to analyze CO2 emissions. The analysis was performed in accordance with the recommendations of the Swedish National Board of Housing, Building and Planning, in the OneClickLCA (LCA tool) and by using specific data (ie environmental product declarations) and also more generic data that best represented the case. The results showed that modules A1-A5 were contributed to approximately 94.8 kgCO2e/m2 floor area. The materials with order of high to low CO2 emissions were respectively metal, insulation, wood and gypsum boards. Replacement of the insulation and gypsum boards to more environmentally friendly alternatives provided significant carbon footprint reductions. In addition, the CO2 emissions caused by the transport of wood materials could be reduced through replacement to more local alternatives. As a result, the new scenario which adopted all these alternative solutions could result in approximately 77.68 kgCO2e/m2 floor area which was almost 18% lower than the CO2 emitted from as-built design of the building case.   The conclusion of the study could be summed up that (1) there is an environmental benefit by using locally produced materials, (2) significant reductions in carbon footprint could be obtained by replacing materials to more environmentally friendly ones, which were also produced locally. All these indicated that the requirement on climate declaration can form the basis for making more conscious choices and reduce the carbon footprint of buildings from a life cycle perspective.

Energy efficiency of the building sector is a key strategy to achieve national climate goals in Sweden and other European countries. In this thesis, several renovation scenarios for a case study office building in Sweden are analysed and compared based on their energy performance, environmental impacts, and economic costs from a life cycle perspective. As a baseline, the case study building was simulated in IDA ICE and compared with the simulated renovation scenarios. For the Life Cycle Analysis (LCA) and the Life Cycle Costs (LCC), the commercially available software OneClickLCA was used. The renovation scenarios were carried out over three rounds: (i) material type scenarios where five insulation materials (glass wool, rock wool, hemp fiber, Expanded Polystyrene (EPS), and Extruded Polystyrene (XPS)) and two frame materials (wood and steel) are compared; (ii) insulation thickness optimization from economic and environmental performance perspectives (iii) comparison of combination with other typical renovation measures such as changing of windows, improving specific fan power, heat exchanger efficiencies, and lightings. The results show that glass wool gives the most economical and environmental performance, followed by rock wool and EPS. When considering other environmental indicators, hemp fiber presents the best environmental option. However, it is not competitive with traditional insulation materials from an economic perspective. The insulation thickness scenarios show different optimal economic and environmental performance points, giving total energy savings of 5 % and 9,5 %, respectively. When considering other typical energy efficiency measures, the highest impact on the energy performance was found when improving the specific fan power (SFP) and switching to LED lights with total electricity reductions (including user-based electricity consumption) of 4 % and 14 %, respectively. Conclusively, the case study showed how the electricity and heating demand of the studied office building could be reduced, and the environmental and economic consequences of the different energy-efficiency measures.