How a tankless water heater works

A tankless water heater works by heating water only when there is demand, rather than keeping a full tank hot at all times. Often described as an on demand system, hot water is produced as soon as you open the tap. While this sounds simple enough, it also raises a fair question. How does a tankless water heater work without a storage tank? If you’ve ever wondered what’s happening behind the scenes and how the water gets heated without a storage tank, here’s how a tankless water heater works.

How does a tankless water heater work

As we’ve mentioned, a tankless water heater works by heating water only when it is needed instead of storing it in a large tank. There’s no reserve of preheated water, which is why these type of water heater systems are typically more energy efficient and take up significantly less space than traditional water heaters. Here’s how a tankless water heater works:

1. The hot water tap is turned on

The moment you open the hot water tap, whether it’s in the shower, sink, or washing machine, the tankless water heater detects a demand for hot water.

2. Cold water flows into the unit

Cold water enters the heater through the inlet pipe and moves directly into the heating chamber. With no storage tank involved, the water moves directly into the heating system instead of sitting idle.

3. The heating mechanism activates

Inside the unit, an electric heating element or gas burner switches on as soon as water begins flowing. The unit heats the water in real time as it passes through, raising it to the set temperature within seconds.

4. Heated water is delivered to the tap

Once heated, the water flows straight to the open tap. As long as the tap remains on, the system keeps heating water continuously, providing a steady supply without the risk of running out.

5. The system shuts down when demand ends

Lastly, when the tap is turned off, the heater stops heating water immediately. Because it only operates when hot water is needed, energy is not wasted keeping unused water hot.

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And that does it for our guide about how a tankless water heater works!