Drivers of Thermal Retrofit Decisions – A Survey of German Single- and Two-Family Houses

The German government is committed to reducing the primary energy demand of buildings by 80% by 2050. This requires increasing the rate of thermal retrofits from the current 0.8% to 2.0% per year. To explore how new and existing policies and programs could deliver the increased retrofit rate, this paper examines the thermal efficiency retrofit decision-making process among owners of single- and two-family homes. It is based on a survey of 2,000 households that have been divided into three categories based on where they were in the retrofit decision process: 1. Households that have neither implemented nor are planning a retrofit; 2. Households that are planning a retrofit within the next two years; and 3. Households that have implemented a retrofit within the last five years.