Living Stingy: Insulating Your Garage Door - For CheapWith about $120 of plastic-coated polystyrene (Styrofoam) we were able to insulate the door in about two hours.  The material was bought at Lowe's.  We bought 8 sheets for about $13 apiece.   We used seven.   The foam is coated with foil on one side, and a clear plastic on the other.  We used the clear plastic on the inside, as it provided an attractive, wipe-clean surface.
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