Blue board is cheap and a small AC from wally world is about 60 bucks, So it is possible to do for about what he says. I would love to see the framework and how he framed it out and how thick the insulation actually is. I was originally going to build a blue board room 8X8X8 using furring strips and blue board with Duct seal tape (Silver Foil backed, super sticky) Then set the small AC on a cinder block high platform and blow it directly into the "room" . Most of those tiny little AC's even have a remote so you could adjust it from across the room. Hmmmmm, got me thinkin now....but I got too many projects going already.