IT Industry analysts estimate there are over 11 million servers in use in 2012, growing to almost 13 million by 2020. While many large data centers are addressing energy use, half of the energy consumption for U.S. data centers comes from small server rooms and closets. These server rooms are often overlooked, despite the significant opportunity to reduce energy through increased utilization, migrating computing needs to the cloud, and employing best practices for cooling and power supply. This presentation quantifies the energy use, and saving potential, for facilities ranging from small server rooms to multi-megawatt data centers. It also compares various sustainability metrics, discusses barriers that stem from lack of information and misaligned incentives, and covers the stats, metrics, and efficiency of moving to the cloud from on premise.