Night Storage heaters do save money by using cheaper night time electricity to store heat in bricks which then warm the room they are in during the day. They work in combination with the Economy 7 rate which all electricity suppliers offer. It turns on at 00:30 GMT and off at 07:30 GMT every night.
The night rate is typically half of the day rate which in my case is 8.1p per kilowatt hour at night and 16.6p during the day so a lot of money can be saved!
I only have one storage heater for my studio flat but typically people have one for each room of their flat or house.
.
Mine has is an input setting with a maximum of 5 for use during the coldest weather, lower settings down to 1 for less cold days and * for off. It also has an output setting with similar values which adjusts the booster which is supposed to allow more heat to escape later in the day if you need it (5 for maximum boost and * for no boost). It works by raising or lowering a damper flap which allows the air heated by the bricks to be convected into the room to enhance the heat radiated from the metal body of the storage heater. Most storage heaters have these controls which always serve the same purpose: to control the amount of electricity to be used during the night to heat up the bricks and to enhance the amount of heat radiated during the day with convected heat if required.
.
.
There are two problems:
- While the Economy 7 electricity is on during the night, a storage heater releases a substantial amount of heat which makes a bedroom too warm for comfortable sleeping and heats other rooms when they are not being used. This results in more electricity being used than necessary which is a waste of money.
- When you turn a storage heater down or off because the weather is warmer, if you suddenly have a cold day or spell you have to wait until the next day before enough heat can be restored to warm the room again.
I have solved both problems by folding a fire blanket into a narrow strip and laying it over the top of my storage heater so that it covers the grill through which heat is supposed to be convected only when the booster is on (damper flap open). However, in practice, heat is continually lost by convection of air heated by the flap itself when it is closed because it is made of thin metal which is not insulated!
The fire blanket reduces the amount of heat lost in this way and I’ve discovered that with the input set to 3 during the warmer months, when I would normally turn the storage heater off, it only uses 4 kilowatt hours of electricity overnight instead of 11. This means that if I suddenly get a cold day all I have to do is lift the blanket to allow more heat to escape. Then during the night more kilowatt hours of electricity will be used than usual to restore the extra amount of heat lost.
If I remove the blanket during the day, I put it back again before I go to bed to make sure that the minimum amount of heat is lost while the bricks in the storage heater warm up during the night.
This solution may well reduce the amount of electricity to keep my flat warm during the cold months as well. Normally when I use the maximum setting of 5 the storage heater uses 13 kilowatt hours of electricity but with the blanket in place it could go down to 11 because it won’t be wasting too much heat warming up the room while I’m sleeping. I won’t know if this is so until the Winter but it does seem quite likely. This means that although I am now keeping the storage heater running all the year round, instead of just during the colder months, I could end up with my electricity costing the same as before or even less.
I used a fire blanket because it is safe up to 900°C and the bricks inside a storage heater only heat up to 250°C. If I had used a towel which has a fire point of 205°C that would have been very dangerous!
.
BACKGROUND INFORMATION
A storage heater consists of a core of high density heat storage bricks surrounded by a carefully designed insulating case. During off-peak periods elements within the brick core heat up the bricks to a temperature level determined by the setting you select using the input control knob for the prevailing weather conditions.
During the following day the heat stored in the brick core is gradually transmitted through the insulation and out of the heater case by radiation.
In the morning, when the core is at its hottest, the amount of heat being transmitted through the insulation and emitted as radiant heat is at its greatest and the heater feels hot over most of its upper outer surfaces.
As the day progresses, heat is transmitted from the heater to the room and the outer surface of the heater becomes less hot and the amount of heat released in this way becomes less.
If the amount of emitted heat becomes insufficient the output of the heater and thus the room temperature may be increased by means of the Output Control (booster). This control operates a damper flap within the heater which, when the output control knob is at minimum, covers vertical airways which pass directly through the center of the core of the heater.
Even when the outer surfaces of the heater are noticeably less hot, the core of bricks can still be at a relatively high temperature. Opening the damper flap by moving the output control away from minimum allows the room air to circulate through this hot core and release more heat to the room by convection.