Jakarta Green Building User Guide : Volume 1- Building Envelope

Building envelope is comprised of opaque components (e.g. walls) and fenestration systems (e.g. windows) that divide the interior of a building from the exterior environment. Building envelope provides protection from the elements of external environment such as heat, radiation, wind, rain, noise, pollution etc.). Building envelope has a key role in reducing cooling and lighting energy consumption. For a typical mid and high rise building, the walls have considerably larger area than the roof. Therefore, care must be taken to control heat gain through the vertical surfaces, especially the windows. For low rise building where the roof becomes the larger part of the building envelope, heat transmission from the roof might be the determining factor of the overall cooling load. Additionally, windows and skylights in the building envelope dictate the amount of light that penetrates inside. By optimizing the window design, most buildings can significantly reduce their electric lighting without adding too much heat gain.