In the following work, we have implemented a version of the hourly method in the ISO 52016-1:2017 standard, informed by the central input table in the SN/TS 3031:2021 specification, including a building energy supply system modelled according to the specification. A case study shows that the model compares well to measurements in unoccupied periods and that openly available gridded weather data can substitute data collected by the weather station on site. A more refined representation of boundary conditions and additional user inputs may be needed for other housing typologies than what can be recreated from the table, but we find that some of this information can be stipulated using open spatial datasets and tools. The results are presented in a web-service dashboard, maintaining continuity with operation phase data collection.