How many renters would even want to replace appliances, get new insulation installed, get all their lights replaced, etc.? I had a bunch of work done after a kitchen fire in my house and it did genuinely cut my electrical bill. It also cost a lot of money and is something I wouldn't have done by choice especially in a rental property.
It was noticeably reduced when I took the time to 3M wrap all my windows one winter, but I didn't want to do it again.