I have a 5' x 10' pantry that I'm trying to keep cool (approx 60 degrees) year around for storing canned food and wine. Two walls are exterior (mostly facing east so get lots of sun hitting walls in morning/afternoon), and house is on slab. I live in eastern Washington so room gets plenty cold in winter but also gets very warm in summer. House is a 1950's build with 2x4 framing.
My thoughts were to double the 2x4 framing on exterior walls to add another layer of insulation. My main questions are, should I add insulation to two interior walls to keep a consistent temp in room? How to get some air circulation? I was thinking of adding an exhaust fan on timer to keep air from getting stale and keep moisture level down if a problem. I'm trying to avoid adding a wall a/c unit if possible to keep temps down in summer.