The building sector is a key focus area of the Energy Concept of the German Federal Government, among other reasons because it has the potential to avoid a large share of CO2 emissions while also saving costs. Thus far, however, only a small percentage of residential building owners have undertaken comprehensive thermal retrofits, and the target retrofit rate of 2% remains a distant goal. In order to address this low retrofit rate, the Conciliation Committee of the Parliament is currently discussing whether to offer residential building owners a tax incentive for undertaking retrofits that are in line with KfW 85 (roughly 15% better than the new build standard). The main point of contention in the current discussions is the distribution of costs for these tax incentives between the federal and state government levels. In addition, some critics have raised questions about the cost and effectiveness of the current proposal, including whether single or comprehensive retrofits shall be supported, what retrofit depth shall be supported, how much flexibility for the completion of projects shall be granted, and what additional support for stepwise retrofits needs to be given. Because retrofit practitioners have experience with these questions, we have undertaken a survey of 78 thermal retrofitting practitioners (architects, engineers, craftsmen, energy consultants, etc.).