"A tankless, or on-demand, water heater only heats water when you need it, not only is it cost efficient, it's ecologically sound.These heaters can be installed in a closet, on an exterior wall or any convenient place inside your home. A tankless heater can heat your whole home or just a single point of use. With point of use, you can have a separate water heater designated for a specific shower, sink or appliance."
"These water heaters give you an endless source of hot water, all while saving money on energy costs by not heating and reheating the same tank of water. While the initial purchase and setup is more expensive, homeowners find that with the energy savings, the appliance will definitely pay for itself after a few years."