The moment steel sheeting gets cold it produces a problem where It truly is colder inside the constructing than out. To beat this you will need an insulation that doesn't drop its thermal defense (like fiberglass) when you have to have it most - Cold damp problems! Ready to get https://opensidecontainer40ft99156.ampedpages.com/everything-about-20-ft-reefer-container-cost-58080070