Implementation of energy-efficient windows in Swedish single-family houses

► Energy cost reduction, age and condition of the windows guide replacement decision. ► Majority of homeowners' were unaware of windows with U-value <1.2 W/m2 K. ► Sellers/installers were the most influential actor in homeowners' window choice. ► Window sellers/installers do not usually recommend windows with U-value <1.2 W/m2 K.