In this session, the speaker will discuss the importance and value for facility managers and owners to undertake either a retro commissioning and/or an energy assessment, and why these are two different exercises. A building’s energy performance loses its effectiveness over time with most buildings becoming 25% less efficient after only a short 2–5-year time period from the original construction and initial commissioning. Operational efficiency can be significantly improved upon with a small amount of effort with changes that improve both energy performance while also improving operational performance, reduced energy, and improved carbon emissions.