At IREES, the Invert/EE-Lab model family for techno-economic building simulation is being expanded to include a thermal-dynamic building model with high temporal resolution. The existing library of reference buildings is assigned a library of typical heating and cooling demand profiles using the expanded model based on building physics parameters and local temperature and irradiation data. The reference buildings that match the local application can be selected from this library using input parameters. To systematically determine waste heat potential with energy quantities and temperature levels, a combination of top-down and bottom-up approaches is chosen. The top-down approach is the identification and characterization of larger waste heat locations, which result from the reporting data from the 11th Federal Immission Control Ordinance (BImSchV) or from European registers (e.g. EPRTR) through participation in the EU ETS. In the bottom-up approach, smaller waste heat sources are characterized using company registers and industry-specific waste heat factors. Similar to other studies, the investigation only focuses on waste heat sources with a temperature of 35°C or more.