When using ElumTools, you may notice that it adds to the Revit file size. The primary reason for this is data stored by ElumTools to recall the renderings for previously calculated environments. Typically each rendering will be on the order of 500 KB but can range up to several MB for complex environments.
ElumTools stores the rendering data in a manner that should not degrade Revit performance. However, if you prefer to reduce the file size, you can delete the renderings as shown below.
You can also elect to never save renderings in the ElumTools settings.