Cold-formed and hot-rolled steel buildings differ primarily in their production processes and the resulting structural characteristics. Cold-formed steel, used in metal structures like cold-formed building kits, is shaped at room temperature, resulting in increased strength and a lighter weight. This process involves rolling or pressing steel into sections without the application of heat. In contrast, hot-rolled steel is processed at a much higher temperature, which can reduce its strength slightly but makes it easier to shape into larger sizes. Cold-formed steel is typically used in lighter, more precise applications like residential and commercial buildings, whereas hot-rolled steel is favored for larger industrial projects due to its ability to accommodate larger loads.