A building's envelope is an integral and necessary part of a building providing protection from the elements but also adding to its visual appeal. These panels are designed to be durable, weather-resistant and low maintenance, suitable for many climates and architectural styles. Exterior wall panels can be made from materials such as wood, metal or composite materials, and each type has different insulation qualities, strength and looks. The use of exterior wall panels can improve a building's energy efficiency by introducing extra insulation decreasing heat transfer and producing a stable indoor environment.