How Water Heaters Work

It is so amazing how cold water flowing through the pipe comes out hot to fit your need during the adverse weather conditions. That is why water heaters have become part of our everyday life and isn’t exactly a new word.

However, to ensure that the unit installed in your home functions efficiently and lasts as long as possible, it is then paramount to know how the water heater works. This will help you to troubleshoot some minor issues when they arise.

Apart from the fuel source which could be electric, gas, propane and solar, there are basically two types of water heaters:

  • The tank-based water heater
  • On-demand or tankless water heater

The Inside of a Water Heater

Let’s dive in a little bit to see the components that work together to give you that early morning fun shower.

Tank: the traditional water heaters are constructed with protective heavy metal that can hold as much as 40-60 gallons of hot water at 50-100 PSI ( pounds per square inch) at the normal pressure range for the residential water system.

The outside of the water heater tank is covered with an insulating material called the polyurethane foam.

Dip Tube: 

Coldwater passes through the dip tube into the water heater and further travels to the bottom of the tank where it gets heated.

Shut-off valve: This restricts water flow into the water heater. The shut-off valve can be found outside, and above the units ie it is a separate component from the heater.

Heat-out Pipe: Located at the top of the tanks interior, the heat out pipe allows for easy passage of hot water out of the water heater.


The thermostat is a temperature-control device. It is also referred to as a thermometer.

Heating Mechanism- the gas water heater use burner and chimney system while electric water heaters have heating components in the tank

Drain Valve

This is found near the bottom of the exterior housing. It helps empty the tank as well as remove the sediments.

Pressure Relief Valve

This is a safety device that helps regulate/maintain the pressure in a water heater.

Sacrificial Anode Rod

Produced using aluminum or magnesium steel core, this rod is placed in the water heater tank to help hinder corrosion.

The heating process

The thermostat in the water heater regulates the temperature of water in the tank. Though the temperature often used is between 49 to 82 degrees Celsius (120 to 180 degrees Fahrenheit). The range recommended by most producers/ manufacturers is 49 to 60 degrees Celsius (120 to 140 degrees Fahrenheit) which is much safer.

Coldwater passes through the dip tube from your homes water lines to the bottom of the tank where the heating process begins and continues until the required temperature is reached.

The higher the temperature of the water heater, the higher the energy being used up, and this implies that in reverse, the same rule applies. Hence, lower temperature means more significant savings on energy.

If you’re having issues with your water heater and need water heater repair or you want more clarification on how the water heater works, do well to contact experts at Just Water Heaters, to enjoy advanced services.