The decarbonisation of the German heating sector is challenging but necessary when aiming to limit global warming to 1.5 °C. Therefore, a fast reduction of the energy demand side and an increase of renewable energy on the supply side is required. However, related efficiency (energetic modernisation) and consistency (renewable energy) measures are limited through their potential, expansion speed, resources and acceptance. Sufficiency as an underrepresented measure has a high potential for heat demand reductions and can thus also relax pressure on the supply side. Nevertheless, sufficiency measures in the heating sector have not been investigated thoroughly. In this study we present scenarios for the German heating sector including efficiency, consistency and sufficiency measures and analyse their compliance with limiting global warming to 1.5 °C. The results of the model-based analysis show that efficiency measures and renewable energy in combination with heat pump expansion are not sufficient. Sufficiency measures, such as a reduced living space, have a high CO2-emission reduction potential and must be considered as one important pillar for a successful heat sector transformation.