Issue: Energy analysis using conceptual masses cannot be performed unless the energy analytical model is enabled.
Solution: Click Yes to proceed, or click No to cancel. If you select Yes, Revit enables the energy analytical model and runs the simulation.
For future simulations, you can enable conceptual mass energy analytical models at any time. Click Analyze tab
Energy Analysis panelEnable Energy Model. For more information, see Energy Analysis using Conceptual Masses - Enable the Energy Model.