Renovering av 70-talsvilla med avseende på energibesparing och klimatpåverkan

Sammanfattning: The climate impact of the construction sector, due to energy and material usage, constitutes the largest global climate burden. In Sweden, the construction sector accounts for 40% of the total energy consumption and 18% of greenhouse gas emissions. The country aims for net-zero emissions by 2045. Despite efficient new buildings, total energy usage in the sector is increasing. Enhancing energy efficiency in existing buildings is vital to reduce its climate impact. Prioritizing renovation of existing structures, instead of building new construction, is an effective strategy. This study aims to evaluate energy savings and climate impact of diverse renovation measures on 70s villas. The goal is to identify the renovation measure with highest energy savings relative to their climate impact throughout various stages of its lifecycle, productstage, transportation and construction process stage. Calculations were done using VIP-Energy and Byggsektorns miljöberäkningsverktyg. The study's calculations are based on a 1970s detached house in Ängelholm, used as a case study with an assumed remaining lifespan of 50 years. When calculating energy savings, the total savings over 50 years were included. Regarding climate impact, the analysis period implies the number of times a measure needs to be carried out during that time. The frequency depends on the technical lifespan of the renovation measure. Renovation measures included extra insulation for walls, upper level floor, crawl spaces, window replacement and installation of an exhaust air heat pump. Three insulation materials researched were: mineral wool, wood fiber and cellulose. Results for all measures were presented in terms of saved kilowatt hours per kilogram of CO2 equivalent emissions. The results show that upper-level insulation provides the most energy savings per kilogram of CO2 emissions, regardless of choice of insulation material. This is due to its longer technical lifespan, reducing overall climate impact. Installation of an exhaust air heat pump showed significant energy savings thanks to its ability to use recycled exhaust air for water heating. The results for window measures show how the choice of window frame material is directly linked to the extent of climate impact during window replacement.