Because system families are predefined in Revit LT, you can only load system family types in projects or templates.
To load system family types, you can:
- copy and paste one or more selected types from one project or template to another
- transfer all system family types of a selected system family or families from one project to another
Copy and paste system family types when you only have a few system family types that you need to load between projects or templates.
Transfer system family types when you are creating a new template or project, or anytime that you need to transfer all the types of a system family or families.