The way water heaters work is by heating the water from the bottom of the tank, where the heating elements are positioned. Due to cold water being denser, the hot water then rises to the top of the tank where it is then carried off to its destination. It is advised not to use all of the hot water too quickly, because if you are using more than the heating elements can keep up with you will run out in the middle of whatever you are using the water for, for instance a shower. Water heaters are fitted with an instrument known as a Thermostat, which acts to ensure the heat of the water in the tank never drops below a certain level (whatever it is set to). If it does, then the thermostat kicks in and powers the heating elements which then warm the water. The thermostat should be set to come on at specific times, when you are most likely to need hot water. By doing this, it lessens the chance that you will run out of hot water when you least want to.



All electric water heaters must be built with a TPR (Temperature Pressure Relief) valve, to prevent them from blowing up if the temperature or pressure reaches an unsafe level. This works to release the excess pressure (in the form of steam or water) through a safe outlet, often piped below the fitting and sometimes even leading outside. The valve should be tested manually on a regular basis, as the effects of the tank exploding can be very dangerous.

Another important feature of a water heater is the drain valve, which allows for any sediment build up to be released. Sediment is one of the main causes of water heaters failing, and it is recommended that the drain valve be flushed at least every six months, to prevent any blockages and damage to the tank.

The anode is another key aspect to a water heater, preventing electrolysis from eating away at the tank itself. Instead, the anode (often magnesium of aluminum based) will attract the corrosion. It is again necessary to check the anode regularly (most modern tanks will have an easily accessible ‘port' where the anode is held), because once it has worn away completely the corrosion will start to eat at the tank.

The inner tank that holds the actual water has to be insulated to prevent unnecessary heat loss, and often the surrounding pipes are also layered to ensure no heat is lost when the water is traveling to its destination.

There is a big emphasis on environmentally friendly water heaters and energy saving appliances, as up to 20% of your heated water is wasted through poor insulation or poor management of your heater. Not only does this have a negative effect on the environment but it also means your household bills will be more expensive.