Water heating is typically the largest base load and the first or second largest energy end use in homes. Significant amounts of energy and water are wasted by inefficient hot water systems. This class focuses on hot water as a system in both new and existing residential applications. Topics include water heaters, piping, hot water outlets, drain water heat recover, and integration with solar thermal. Additionally the session includes time to discuss what mechanical options are available to improve hot and cold water systems efficiency.