How to Use an Immersion Heater

Immersion heaters are convenient small appliances that can boil water on the go for tea, coffee and instant soup. Immersion heaters can also be larger for specific uses such as in an aquarium or water tank. Travel immersion heaters are compact tools that are versatile for traveling and use in an RV. Basic immersion heaters can hang on the side of a mug or pot to boil water; other immersion heaters have thermostats to control the temperature or to shut off when a target temperature is reached. Immersion heaters generate heat through electrical coils or oil-filled tubes, so care should be taken to appropriately cool the appliance to prevent cracks in the heating element.

Step 1

Place the immersion heater in your container by hanging it over the lip (side) on the inside of the mug or pot.

Step 2

Fill the container to the designated level on your immersion heater (do not submerge the heater and make sure the coils are not exposed to air). Fill the second container with water and set aside (this is your holding container).

Step 3

Plug your immersion heater into the power outlet. Monitor the contents of the container for boiling over the sides and for overheating (i.e., boiling dry). When the liquid is hot, unplug the immersion heater from the outlet and wait a few minutes before transferring the immersion heater to the holding container to cool off.

Step 4

Pour your hot water into your instant soup cup or add tea, coffee or hot chocolate as desired.


  • Do not use a plastic, paper or Styrofoam container that can melt or burn when in contact with the immersion heater or hot liquids.
  • Be sure to immerse your heater to the level indicated in your manufacturer's instructions.
  • Do not completely submerge your immersion heater in liquid (unless it specified by the manufacturer).
  • Do not let your immersion heater boil the liquid dry.
  • Never leave your immersion heater unattended to avoid a fire hazard.
  • Do not touch a hot immersion heater or lay it down on a surface before it has cooled.