This guide presents a process for increasing building energy efficiency by commissioning new and existing buildings, monitoring their performance, and taking actions to ensure persistence of savings. Commissioning existing buildings can provide an energy savings of 10% to 30%. Median energy savings from commissioning existing and new buildings are 16% and 13% whole — building savings respectively. Note that savings can be much greater than these median numbers — 25% of existing buildings saw whole-building energy savings of 30% or more . It can also reduce risk by helping to ensure your building performs as designed. While calculating “savings” for a new building is difficult, researchers estimate that a building that is not commissioned may consume 5% to 10% more energy than one that is commissioned. Commissioning services vary in scope and in cost; one study suggests that median costs for commissioning existing and new buildings are $.30/square foot and $1.16/square foot, respectively . Because commissioning is often not done due to a lack of understanding of the process and benefits, this guide intends to help you to understand both the process and the benefits.