Claytex/TECHNIA has been working with the Energy Systems Catapult to improve the Catapult’s cutting-edge dwelling simulation tool, HED (Home Energy Dynamics). Aimed at reducing carbon emissions from dwelling heat usage, HED’s modular approach to constructing simulation models leverages benefits of Dymola/Modelica to make simulation usage accessible to more people within organizations. Excel macro generated GUIs empower the user to construct detailed Dymola models without needing specialist simulation knowledge. Deployment of Claytex/TECHNIA’s MultiRun batch simulation tool has empowered the Catapult to conduct batches of dwelling permutations (heating strategies, evaluation of energy recovery systems etc) by drastically reducing the simulation time of each batch. Such an approach enables the Catapult to conduct dwelling simulation studies lasting a year or more each, in a timely and manageable manner.