The Building Envelope refers to the exterior facade, and is comprised of walls, windows , roof, skylights, doors and other openings. The envelope protects the building’s interior and occupants from the weather conditions and other external elements. The design features of the envelope strongly affect the visual and thermal comfort of the occupants, as well as energy consumption in the buildings.
A well-designed building envelope not only helps in complying with the Energy Conservation Building Code (ECBC) but can also result in first cost savings by taking advantage of day lighting and correct HVAC system sizing. This document acts as a primer on better envelope design practices and steps needed to comply with ECBC.
Building Envelope : Exterior and the semi-exterior portions of a building. For the purposes of determining envelope requirements for the ECBC, these are:
- Elements that separate the conditioned spaces from the weather conditions, or
- Elements of a building that separate the conditioned spaces of the building from the unconditioned spaces, i.e. office space from unconditioned storage.
An integrated building design considers the Envelope, the Heating , ventilation and Cooling(HVAC) system and the lighting system a whole, rather than dealing with these independently. Changing the specification of one system can effect the performance of the other two significantly.
It may also be a significant task to determine the energy efficiency properties of products that are used for typical construction and building assemblies used locally.
One of the goals of the envelope design should be to introduce day lighting into the interior space of the building through windows and skylights, thereby reducing the need for electric lighting. Thus, giving proper orientation to the building and due consideration to the size and placement of windows at the design stage can provide the advantage of day lighting.