While I do not consider myself as being a coffee addict, I need my fair share of caffeine on a daily basis. While some of the hotels I have been to during my travels provided a small kettle and single serving coffee bags, these hotels have been an exception rather than the norm. As a matter of fact, a few of the hotels I have been to in recent times did not even provide any kind of coffee facilities anywhere in the hotel. It is in situations like this that a portable immersion water heater becomes useful.

Most immersion heaters contain an element which is simply a bent piece of metal rod. Fixed to the element is a plastic handle, a wire and a power plug for connection to the electrical supply. Using it is simply a question of putting the element into a cup or mug that is filled with water and plugging the heater into the electrical supply. The metal rod will then get hot and the water will get warm in the process. While immersion heaters can be used to warm other liquids like milk and soups, it is important to rinse it well after use. Otherwise the liquid may stick to the element and it will be very difficult to scrub it off, rendering the heater pretty useless.

The majority of immersion heaters come very cheap. The top seller on Amazon.com is the 300W NoPro Instant Immersion Heater, only costing $8.25 at the time of writing. While most of the user reviews for this heater are positive, some user comments suggest that the NoPro is not a very durable product.

One of the best-selling immersion heaters on Amazon.co.uk is the Go Travel Cup Boiler. This boiler has a UK type 3 pin plug and is also rated at 300W. Unlike the NoPro this heater has a safety protective cover so that no metal piece is exposed. Being sold at £14.65, the Go Travel boiler is more heavy duty than the NoPro.

Having said this, the Cup Boiler from Go Travel does have a few disadvantages as well. One drawback is the fact that it fairly big and heavy at 200g (7 oz). In view of this it may easily topple any glass that is not a big ceramic mug. Alternatively the heater has to be wedged to another object so that the glass does not fall over with the weight of the heater. Being big also means that it will take a lot of space in a small cup; another good reason for using a big mug. One reviewer also complained that the water tastes of plastic the first few times of usage.

To conclude this article, below is a set of important points one should remember when using any kind of immersion heater:

1. The element should not be touched while the heater is in operation. In the same way one should not put his hand in the water while the heater is in use.
2. It is important to ensure that only the element is placed in the liquid. The wire should not touch the liquid at any time, especially when it is switched on.
3. An immersion heater should only be switched on when the element is in a cup that is filled with liquid. Switching the heater when the element is not in contact with any water or other type of liquid may damage it.
4. The heater should be switched off after the water has been warmed. It only takes about 3 minutes to heat the water and leaving the heater switched on for a much longer period may eventually damage it due to the excessive heat.
5. An immersion heater should not be placed in any luggage when it is still hot. Having said this, cooling the heater is simply a question of rinsing the element under running water.