|Originally Posted by DMF|
Not necessarily true. A non-IC lumenaire can indeed be set in a ceiling with insulation, but it needs a minimum of 3" in all directions clear of insulation.
The electrician may have a good reason (besides cost) for specifying non-IC cans. As I understand it, non-IC cans can be inserted through the hole cut for them. IC cans can't since the housing is much bigger than the hole. If you are re-fitting an existing room, non-IC cans may be your only option.