Re: Insulating around a light where a ceiling fan once was
The best way to seal the leak is to go into the attic, dig out the fiberglass or loose fill material around it and spray foam around the box. Loose fill insulation does nothing to stop air leaks. Actually, because it allows air movement, the actual insulation value is often dramatically overstated.
Replacement is pretty simple. Honestly for resale value, I'd leave the fans and put in a fan with a light. I've noticed that appraisers and relators take notice of how many ceiling fans and such are in a home. It's easy to not use a fan.
1925 Two-Story Stucco Beaux Arts Neoclassical