The greenhouses have two layers of poly with inflation blowers. They work super well!
No, to add an insulating layer of air. Believe it or not the 24 13w cfls add enough heat to make a difference.
I should've gone with the anti-condensate film, which I have on my 30x60 clearspan. That clear poly is almost dripping in the morning. Roll up the sides and its out though..
I love the pallets, they are such an advantage for run-off purposes.