So, I actually did this when expanding my greenhouse! I sold houseplants I had raised, and built the addition bit by bit. The first winter I had the foundation and frame (made of 2x4s) completed, and decided to encase the whole thing in the "big bubble" bubble wrap.
Here were the results -
#1 Bubble wrap IS NOT WATERTIGHT. Many of the bubbles filled up with water. I thought "cool", maybe the water inside will heat up and help with additional heat retention. Well, all the water did was turn green and moldy. Within a month I could not see out large portions of it.
#2 Bubblewrap is not very insulating because in between the bubbles are the flat spots. It did not help insulate the greenhouse much at all.
#3 Bubblewrap tears easily. The first big wind ripped most of it off.
So, I moved the bubblewrap to the inside, and stapled heavy, clear (sort of!) plastic sheeting on the outside.
#4 If you put it on the inside of the greenhouse, humidity/condensation and the weight of the moldy water in the bubbles will cause it to all pull off of the staples and fall down. All over your plants.
SO, I did manage to make it through the winter, but boy was it a LOT of work. Way more work than it was worth.
Sorry.
Carolyn