You are so right with the first bit. I love Supernatural but this whole episode was logic fail.
Like in this episode whenever Bobby was around and about with the boys on the outside, you could see the living's breath. (At the museum, you can really see this.) Because Bobby is a ghost. And on Supernatural, ghosts suck out the warmth in any room making it like an ice box. Why didn't the boys notice their breath before? Why didn't they notice that, no matter what place they were in, the temperature dropped the moment they walked inside of it? In fact, they are hunters. This is Ghost Hunting 101. They should have known better.