Demand hot-water system
Hot-water heaters designed to provide instantaneous hot water, rather than storing preheated hot water in a tank. Such devices can serve an entire home, or be point-of-use, serving an individual water use. Benefits include elimination of standby losses, or energy wasted keeping stored water warm. With point-of-use devices, there is reduction or elimination of water wasted while waiting for water to get warm, as well as conductive losses as water travels through pipes. Electric-demand systems tend to use a large amount of energy; gas-fired units with standing pilot lights lose much of their efficiency due to the ongoing pilot light.
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