How Do Tankless Water Heaters Work?

Tankless water heaters provide heated water on demand, in other words, only as and when you need it. So how do they work? And how do they remain energy efficient?

Step 1: Turn on the Faucet

Turning on your hot water tap gets the whole process started.
 

Step 2: Water flows into the Unit

Water starts to flow into the Tankless Water Heater.

Step 3: Unit Detects Water Flow

Your Tankless Water Heater detects the water flowing through it and initiates water heating. With a gas tankless water heater, this involves starting gas flow to the burners. Electric tankless water heaters have a similar step.

Step 4: Cold Water is Heated

The cold water is now heated.

Step 5: Heated Water sent to Fixtures

The heated water now flows to your tap, faucet, or other fixtures.

 

Step 6: Water is Turned Off

When the faucet or tap is turned off, the tankless water heater goes into standby mode.

For a graphic view of this process for a gas tankless water heater, see here.