Since my husband decided he didn't want to tour the country in an RV, we have bought a small house in town. We bought one of those buildings you see on the side of road everywhere for my new wood shop. The building is 12 x 26 ft. It has the standard 2x4 studs, wood sides and a metal roof. The inside walls and the ceiling have that thin foam board insulation. I'm thinking of adding insulation to the walls of the building but don't know if it will help. One of the narrow ends of the building consists of a canned, roll-up door, which wouldn't be insulated. Since one wall will be basically made of un-insulated metal, will it be worthwhile to add insulation to the other 3 walls? I will be using French cleats to hang everything and eventually installing a mini-split or a combined a/c-heating window unit.