In the analysis “Update: Impact of the Building Energy Act on Residential Buildings”, the EWI examines the effects of the passed GEG of September 8, 2023, on the development of heating installations in residential buildings up to the year 2030. In doing so, the analysis updates the scenarios from the EWI study on the GEG draft of April 2023 and compares the possible effects of the adjustments. The scenarios differ according to the future use of heat pumps, heat grids and gas heating systems. The results show that the stock of heat pumps as an immediate compliance option of the GEG could increase up to 4.8 million in 2030, which is lower than in the scenarios based on the GEG draft. Due to the shortened time span between 2026 and 2030, which is associated with the coupling of the deadlines to municipal heating planning, there are comparatively small differences between the scenarios.