How Does a Hot Water Heater Work?

Have you ever wondered how a hot water heater works? It’s amazing how something that we use everyday can operate without us having any idea.

Not many people think about their water heater until they’re stuck in a cold shower with shampoo still in their hair- yikes!

Hot Water Heater Basics

Most people in BC will have a standard hot water tank. Using electricity or natural gas, your hot water heater will heat the water inside your tank to a preset temperature. It will maintain this temperature whenever it is in operation.

Recently, tankless, “on-demand” water heaters have entered the market. While they still provide hot water, they don’t require a storage tank full of water to keep at temperature. Because of this, tankless hot water heaters are generally more energy and space efficient. Click here to learn more about tankless water heaters.

Gas vs Electric

The method of heating may be different for these types of water heaters, but there is one important item they have in common: an anode rod. This replaceable rod of zinc plays a crucial role in the health of your hot water tank: corrosion prevention. It’s purpose is to corrode so that your hot water tank does not, thereby extending the life of your tank.

Generally, your hot water tank heats water one of two ways:

  1. Gas burners – These heat water by means of a burner and pilot light underneath the tank. A thermostat detects the temperature of the water inside the tank and regulates the delivery of the natural gas or propane being supplied to the water heater to ensure the water temperature does not drop below the preset threshold.
  2. Electric elements – These heat water by means of an element inside the tank itself, much like the kettle you may have in your kitchen. Electricity is delivered to each element through a thermostat which acts as a switch. When the temperature drops the thermostat switch will allow current to flow and heat the water back to the preset temperature.


Instead of storing gallons of water until you need it in a large tank, a tankless water heater system will supply you with hot water- endlessly and on-demand!

Tankless water heaters work by using high-powered burners to quickly heat the water as it runs through the heat exchanger. The incoming cold water circles around the heat exchanger and exits the tankless heater at the pre-set temperature of your choice for as long as you need it, thereby eliminating the need to store water in a large tank.

By heating water only when you need it, tankless hot water heaters save on space and energy.