I remember when I lost all those pounds years ago, I felt much colder. These days, I'm an air conditioning fiend. I keep my house air conditioned all year around at 68 degrees during the winter and 67 during the summers.
If my wife didn't mind, I'd have it down to 65, though. It's definitely the fat insulating your body. Now that insulation is gone.. I do remember my tolerance increasing a little bit after being skinny for a while, but not that much.
It may be safe to assume that you'll be able to tolerate 2 degrees colder than you currently do, but no more than that, probably. When I was skinny, 70-72 degrees was my "comfort level".