To modify window properties with EMS, you need the following:

1. EnergyManagementSystem:Actuator for Surface, Construction State
2. EnergyManagementSystem:ConstructionIndexVariable objects to determine the index for each construction that will be used.
3. EnergyManagementSystem:Program to assign the desired construction state.
4. ShadowCalculation, TimestepFrequency;object.

Example file EMSThermochromicWindow.idf illustrates the use of the construction state actuator. If you add daylighting controls to this, there will be little impact, because the south zone has six or so windows and the EMS is only acting on one of them. Deleting the other windows shows that illuminance tracks the changes in window construction state, but they are lagged by one zone timestep. Reference issue #4266