Comprehensive investigation on energy retrofits in eleven multi-family buildings in Sweden

• The multifamily buildings in the Gävleborg region have high potential of reducing energy use.
• Heat Recovery Exchange (HRX) ventilation system is not profitable.
• Declining population and high unemployment are hinders in reducing energy use.
• Enforcing laws and spreading information will reduce energy use.

Rapidly growing energy use in the building sector is considered a serious problem by both the European Union (EU) and Sweden. Reducing energy demand in the building sector is important for Sweden in order to reach national energy goals for reduced energy use and CO2 emissions in the future. This project aims to find energy efficiency potential in multifamily buildings in the Gävleborg region, which is a cold climate region in Sweden. Measurements and simulations have been made on eleven multifamily buildings from the whole region. The results include different energy efficiency measure packages, profitability analysis of individual measures and packages, and primary energy use analysis. The paper also includes CO2 emissions reduction analysis based on different methods. The project shows that the multifamily buildings in the Gävleborg region have good potential to reduce their energy use by more than 50%, which in turn will contribute to 43% primary energy reduction and 48% CO2 emissions reduction.