Immersion heaters

Using your immersion heater

Using hot water carefully and being energy smart means you will have hot water when you want it and sensible energy bills.

The hot water cylinder is usually situated in your airing cupboard, kitchen or bedroom. The immersion heater is a heating element which is situated inside the hot water cylinder and heats the hot water you and your family use every day, for showers or baths, hand washing, washing up and cleaning your home.

If you have storage heaters in your home, you will be using the cheaper, off-peak electricity tariff, Economy 7, which runs from 12.00 midnight until 7.00 am. The immersion heater will work during the night using the cheaper tariff to heat the water in the cylinder to a pre-set temperature.

In the morning you will have a full tank of hot water which normally will be enough for all your domestic usage during the day.

To use your immersion heater effectively and economically, there are a few important things to remember...

Choose carefully how you heat water. If you need very hot water – use a kettle to boil it. Fill the kettle with only as much water as you need
Be sensible about when you heat water. Check your water heater control to see that you are using the Economy 7 tariff and haven’t accidentally switched to the more expensive daytime tariffs
Use less hot water. If you wash up by hand, don’t rinse the dishes under running (hot) or cold water, use a separate bowl. If using a dishwasher, only run it on a full load
Turn off taps fully and make sure dripping taps are fixed. An unfixed dripping tap can waste enough water during a week which is equivalent to filling half a bath
If you’re not filling up your washing machine. Use the half load or economy programmes, using the machine’s 30°C wash if possible, saving you up to three-quarters the cost of the hottest cycle. Or, handwash small amounts in a bowl
Bath or shower? The traditional advice of taking a shower rather than a bath to save hot water may not apply if the shower lasts more than a few minutes, especially if it is a power shower. De-scale your showerhead regularly if you live in a hard water area, otherwise scale build up will affect the water flow.

Setting the controls

Some properties may only have an on and off switch, but most will have a heating controller. Your heating controller is probably similar to one of the two wall controls illustrated. Both water heater controls have been designed to work off the cheap night-rate electricity and to enable you to boost your hot water supply, if it is needed, during the day.

BX2000 water heater control

This water heater control has been designed to offer flexibility for those using off-peak electricity for water heating. It provides the facility to boost your supply of hot water at any time and to ensure you are automatically connected to the off peak supply whenever it is available.

If you require extra hot water during the day, switch the normal supply electricity to the on position and press either the one-hour or two-hour boost buttons to heat extra hot water. The light below whichever boost button has been selected will illuminate.

Economy 7 Quartz control

This controller has been designed to take advantage of cheap night-rate electricity, so that there is a tank of hot water available for the morning.

Both of the timers are connected to dials on the front of the water cylinder.

If you need to use extra hot water during the day, you will only need to boost the supply for a short period of time by setting the minute timer on the control.

The Economy 7 Quartz upper timer dial is used for regulating the Economy 7 off-peak electricity, whilst the lower dial regulates a timed boost for the water heater which is available any time during the day to heat extra hot water.

Be aware that the cost of using the booster on-peak electricity will be significantly more than the Economy 7 off-peak electricity.

If you are going away, make sure you switch the water heater off.

Immersion heaters without a controller

To make sure that Economy 7 off-peak electricity is being used for heating your water, follow the cable (if it is visible) from the bottom dial on the cylinder to the relevant wall on/off switch. This is the switch for using the Economy 7 off-peak electricity tariff. Check the wall switch is switched to the on position.

The other dial on the wall controller leading to the higher dial on the water cylinder should be switched to the off position as this is the switch for the 24 hour booster on-peak electricity, which is charged at a considerably higher rate. Turn it to the on position if you are boosting your hot water supply but remember to turn it off afterwards.

If you want to cancel the boost setting before the boost time is complete, press the cancel button but don’t forget to turn the electricity normal supply switch to the off position.

If you are going away, make sure you switch off both switches.