Abstract Decarbonising the heating sector is crucial for reducing CO2 emissions. This is in particular true for Central European cities such as Vienna, where 28% of the total CO2 emissions are caused by the energy supply for buildings. One promising option for environmental friendly heat supply is the use of shallow geothermal energy. To determine whether shallow geothermal systems are a feasible option to meet the urban heating demand, the Python tool GeoEnPy is developed and applied to a case study in Vienna. It allows the evaluation of the anthropogenic heat input into the subsurface, the theoretical sustainable potential, the technical geothermal potential, and the heat supply rate. The overall heat flow in Vienna is 17.6 PJ/a, which represents 38% of the current heating demand or indeed 99% once all buildings are thermally refurbished. The technical geothermal potential can satisfy the current heating demand for 63% (BHE system) or rather 8% (GWHP system) of the city area. GeoEnPy reveals that BHE systems are most feasible in the eastern and southern districts of Vienna. Our findings can guide integration of shallow geothermal use in spatial energy management focused on key locations to supply buildings with decentralised and sustainable heat from the subsurface.