Energy savings and CO2 emissions related to measures on an old apartment building

Abstract: There is a clear focus on the environmental question in today’s society. The awareness of energy consumption and emission of greenhouse gases is growing which causes the urge to increase energy efficiency and decrease the emissions. This is applied in all sectors, housing being one of them.Approximately a fifth of the entire energy consumption in Sweden accounts for hot water supply and heating of all housing and facilities. About half of all housing in Sweden consist of apartment building’s. A third of the global emission of greenhouse gases is related to the building sector. This motivates a focus on energy saving measures in the housing sector and especially apartment buildings.In this report the consequences, regarding energy savings, economic profitability and emission of CO2 equivalents, of implementing energy saving measures on an old apartment building have been investigated. The energy saving measures that have been considered are Additional insulation of attic, Additional insulation of external wall, New windows and balcony doors and FTX. The reference building that has been considered in this project is a light weight concrete apartment building with brick facade which was constructed in Stockholm 1948. It has 3 floors, a basement and a total of 12 apartments. This project has been preformed in cooperation with AB Familjebost¨ader.The results regarding energy savings have been brought through energy simulations in the software IDA ICE. The reference building was constructed in the software and simulations were done for each energy saving measure. Another simulation was done combining the measures Additional insulation of external wall and New windows and balcony doors and one simulation combining all measures. A reference simulation was also done to validate that the model building is representative to the reference building.The economic profitability and payback time was calculated, using the net present value method considering the discount rate of 4% and the lifetime of 40 years, for each measure and combined measures. The emissions of CO2 equivalents related to the material used for each energy saving measure were calculated. Additionally, the emissions related to consumption of electricity and district heating were calculated, considering three different district heating suppliers. With these numbers the total amount of avoided emissions due to a measure could be calculated.According to the simulation results Insulation of attic had the lowest energy saving with 3.34% and New windows and balcony doors had the largest energy saving with 27.49%. The total energy saving reached 68.51% when implementing all measures. According to the economic calculations only Insulation of attic is profitable with a payback time of 8.42 years. But the measures New windows and balcony doors and FTX might be profitable if the reference building’s increased value, due to implementation of the measure, is considered. The calculations of the emissions of CO2 equivalents suggests that all measures imply avoided emissions if the current district heating supplier is considered. The amount of avoided emissions varies depending on which district heating supplier is considered and in some cases the energy saving measure can causes more emissions compared to no measure.The recommendation form the author is to go through with the measure Insulation of attic since it decreases the energy consumption and is economically profitable Furthermore, it is recommended to investigate how the measures New windows and balcony doors and FTX would affect the financial worth of the reference building, since that may cause those measures to be profitable.