Retrofitting is the process of evaluating and replacing or modifying existing building components when they are no longer efficient or operating correctly. More efficient building components and processes reduce energy consumption, and often improve occupant comfort and safety. Because well-designed buildings can last for decades, retrofitting is an effective measure for improving efficiency and achieving energy savings without incurring the high costs of new construction.

A standard retrofit takes a “measure-by-measure” approach to building upgrades. This type of retrofit typically involves evaluating which modifications or replacements are the most economical, and only undertaking a list of individual changes. This tends to favor retrofitting projects that are cost-effective, have short payback periods, and are a low risk to building owners.

A deep retrofit takes a more integrated approach, considering the whole building when determining the best retrofit opportunities for energy savings. This type of retrofit looks beyond the cost-effectiveness of individual component upgrades. Instead, a deep retrofit takes a systems-level approach, examining interactions between equipment and other dynamics of the building systems and processes, grouping many upgrades into a single project. Deep retrofits are more intensive and expensive than standard retrofits, but can achieve much higher levels of energy savings in the long run.

A first step in building retrofitting is conducting a building energy audit, in which an experienced professional determines the best energy saving opportunities. Building owners may also use an Energy Service Company (ESCO), which goes beyond auditing to offer a comprehensive retrofit plan that typically incorporates design, financing, installation, and operational elements. After the retrofit, ESCOs will monitor and verify that the installations and other updates are performing as expected.