An immersion heater is an electric heating element that is installed inside a hot water cylinder or tank to heat water. It works by passing a strong electric current through the element, which heats the water around it. Immersion heaters can be installed in different ways, including over-the-side, flanged, or threaded. They are available in many temperature ranges, and their heat output remains constant regardless of the environment or application since the heater’s resistance measurement is also constant.

Immersion heaters are powered by electricity and are connected to their own power supply via a cable. They can be used as the main hot water heater or as a backup water heater for a gas boiler. Immersion heaters can be controlled by a thermostat and timer, which can help to keep energy use under control.

While immersion heaters are a fast, economical, and efficient method for heating liquids in tanks, vats, or equipment, they can be more expensive to use than heating water with gas. However, fitting a thermostat and timer alongside the immersion can help to keep energy use under control. Immersion heaters can be a great option for flats, second homes, and those that live more remotely.