If a tankless water heater doesn have a tank, how does it make hot water?
The tankless water heater doesn’t hold hot water; it heats water as it flows through the heater. Basically, when you open a faucet or turn on the shower, water begins to move inside the heater and flows through a sensor which turns on the blower fan and burner which heats the water as it passes through a device called a “heat exchanger”. Basically, this exchanger is a series of tubes with the moving water flowing inside. The rising heat from the fire chamber heats these tubes and that heat in turn transfers into the water inside the tubing. It is really that simple. The more complex part is the controlling of fan speed and fire levels to deliver a consistant temperature of water depending upon the GPM (gallons per minute) of hot water being required at any specific moment.
