The shop is pretty well insulated. R30 in the attic, walls wrapped with a radiant barrier like thisand then R19 insulation. The weak point was the garage door.
To insulate the roll-up garage door we decide to make curtains out of inexpensive Harbor Freight shipping blankets.
We started bending and cutting 2 pieces of 1/2 inch EMT we had left over. We hung it up with a few eye-screws.
We sewed 2 together to provide the length we need.There are 3 sets that we can easly slide out of the way when we need to use the door.
We can pull it back a little better and tie it to the wall, but you get the idea.