Energy efficiency measures in a typical Swedish single-family building from the 1960s

Sammanfattning: Many buildings built in the 1960s are inefficient when it comes to their energy use. A lot of them are also in need of renovating. Therefore, this project is aiming to investigate five different scenarios where the decrease in electricity demand is in focus.One scenario is energy-saving behavior which does not need any investment for a renovation but just decreases the electricity demand by changing the behavior of the people living there.Another option is the building envelope renovation where added insulation to the outer walls, the roof and the floor is added. The windows and entrance doors are also upgraded to more efficient options. A return air only ventilation system is installed as well. The third option is to renovate the reference house to achieve the status of passive house set by Boverket. This is done by adding a much thicker layer of insulation to the building components and adding a FTX ventilation system and at the same time changing the direct electric heating system to a bed rock geothermal heating system. The last two scenarios, net-zero energy building and off-grid building, also use a FTX ventilation system and bed rock geothermal heating system. They have the same thickness as the building envelope renovation. The biggest difference is that the net-zero energy building uses solar power to match the yearly electricity demand and therefore be able to call it net-zero energy. The off-grid house has an electricity storage as well as the solar panels. This is to be able to disconnect from the electric grid completely and only consume electricity produced by the building itself.The last three scenarios all achieve a primary energy below that of what Boverket demand fornew buildings of 90 kWh/m^2, year. The building with the lowest cumulative cost over 50 years is the off-grid building, though this result could vary depending on the price of electricity. The scenario with the lowest investment cost per kWh saved is the net-zero energy building.