IES Guidelines for Upgrading Lighting Systems in Commercial and Institutional Spaces
Increasing lighting efficiency is often the most cost effective energy efficiency improvement that can be made to an existing building. There are two basic approaches for improving the energy efficiency of an existing lighting system: retrofit or redesign. Retrofitting the existing luminaries will be the more common approach. However, on projects where the existing illumination or lighting equipment no longer suits the space or application, redesign is the better choice. A thorough assessment is necessary to determine if one (or both) of these methods is advantageous over the other.