The FOB Kalundborg renovation project’s expected CO2 savings were doubled by an external financing of just 8 percent of the total renovation budget. The additional investment enabled the replacement and re-insulation of technical installations. Furthermore, intelligent management was installed, which helps to reduce energy consumption and to ensure a better indoor climate for the tenants. The additional investment also paved the way for new and energy-friendly windows, and for optimal insulation of facades, exterior walls, and gables. In total, the project has realised savings on heating, electricity and water, amounting to a reduction of approximately 600 tonnes of CO2 per year.