Just like you wouldn’t leave the heating systems switched on in your home when you are away for a vacation, wouldn’t it be a whole lot wiser if you were using heating systems for water only when you were actually using the hot water? Conventional water heaters heat your water and then save it all up in a tank and wait for you to use it. This seems pretty convenient. After all, when you do need the water, it is all ready and available. However we rarely realize the amount of electricity that would be wasted in maintaining the hot water at its given temperature. also, there is only a limited supply of hot water at a go, when it finishes off, you must wait for another long while before more water becomes available. The solution to all of this? Tank-less water heater.
Tank-less water heaters can heat water without the need for any kind of a storage tank. They do so by being an intermediate step between the cold water line and the hot water tap. When you need hot water, you simply turn the tap on, as the water starts flowing through the pipe, sensors switch on the heater which then heats the water as it travels to the tap. Usually these units have a long coiled pipe inside of them which allows water to travel a greater distance inside the unit, hence allowing greater time to heat the water. The heating element can be electric or gas. In case of electric element, high resistance coils are wound along the length of the pipe, hence allowing the pipe to get heated up on demand, and hence heat the water as it flows through it. In the other case, gas is used in small burners which too in turn do the same thing by heating the pipe up.
Of course, there are limitations to using such devices. They do not allow fast flow of water which is possible with storage tank heaters, since they are just emptying the tank. The water flow may be slow, but it would be consistent and indefinite. Since there is no storage system, hot water would keep flowing as long as you need it. For a household, it would be wiser to get multiple units or booster units to ensure consistent supply of water because high requirements can take a toll on this system. The benefits of going through the trouble of installing these systems is immense, they can bring down the energy usage by 1/3rd for a house that uses 41 gallons of hot water in a day.
Which tank-less water heater you use would depend on your location and your requirement. Locations makes a difference because the incoming water temperature would play a major role in deciding which heater you need. Also if your necessary temperature rise is achievable by gas or electric heating element would decide the kind that you choose. But rest assured, whichever heating system you may use, using tank-less water heaters would help save energy.