Commercial service hot water heating design requires care, to ensure delivery of hot water to the most remote fixture within a reasonable period, to reduce the waste of water. Commercial buildings will usually incorporate a recirculation water loop, to keep primary plumbing piping filled with heated water. Recirculation energy losses, due to pump energy, as well as heat transfer, can be substantial. An alternative is to use point-of-use heaters. Electric tankless units are compact and can be installed underneath each plumbing device that requires hot water. Temperature regulation is good. Designers should utilize care to understand a building's potable water quality and to coordinate electrical requirements early. Buildings which derive electrical energy from utility companies reliant on coal based plants should analyze the overall impact of point of use heaters on greenhouse gas emissions, versus natural gas systems.