Difference between Water Heater and Geyser

Key Difference: Water heater refers to any type of system which is used to heat water. These water heaters can be either electric or fuel fired. In U.K. and some commonwealth countries, geyser is used to denote a type of water heater which is used for domestic purpose.

Water heater refers to any type of system which is used to heat water. Water heaters are often used during the winters, specifically in the households. Water is such an important compound in our life, that we cannot imagine this world without it. However, during winters, the temperature of the water also falls down, and it is quiet cold even to touch. During the winters, one needs to use warm or hot water. For heating the water numerous appliances can be used like a water heating rod, kettle, solar water heating system, etc. All these appliances fall into the category of a water heater as they use an energy source to heat the water.

Most of the houses are equipped with a tank type water heater. These water heaters can be either electric or fuel fired. One can also heat water in kettles, pots, etc, if not much water is desired. Water heaters must be properly handled as there is a possibility of an explosion. In big water heater devices a safety valve is present as a precautionary step.

The term geyser is used in many contexts. Originally, geyser refers to a natural fountain or spring that intermittently throws a tall column of water and steam into the air. Based on this definition, informally sometimes it is also used interchangeably for a water heater. Geyser can be defined as a type of water heater, which provides continual supply of hot water. The word may be used for different types of water heating systems. For example- In British English, it refers to a water heater through which water flows as it is rapidly heated (specifically gas fired), whereas in South Africa, the term is used to define a hot water storage tank consisting an electric heating element.

Comparison between Water Heater and Geyser:

	Water Heater	Geyser
Definition	Water heater refers to any type of system which is used to heat water. Water heaters are often used during the winters, specifically in the households.	Generally, it can be used to define a water heater, which is used for domestic purpose. It is generally associated with continual supply of water. In British English, it refers to a gas-fired water heater through which water flows as it is rapidly heated. In South Africa, the term is used to define a hot water storage tank with an electric heating element.
Origin	Water + heater	From Icelandic Geysir, the name of a particular spring in Iceland; related to geysa 'to gush'
Type	Can be any type – an immersion rod, kettle, tank based, etc.	Gas or electric based
Other meanings	No	Geysers refer to natural fountains or springs that intermittently throw a tall column of water and steam into the air.