Storage Heaters – How They Work

08 May. 2019

Written by Neil Marsh MCIPHE RP RHP EngTech


Below we have provided information about storage heaters and how they work. We do not rate storage heaters for performance, and in many instances efficiency, as we believe using such devices are not an effective way of heating parts of a property…

Storage heaters are usually installed in properties with Economy-7 electricity meters. These are generally used in properties where there is no gas supply present which are smaller in size, such as that of flats or smaller properties that are not connected to mains gas, like those in the countryside. The idea is that the occupiers of the properties are provided with an affordable way to heat their homes and hot water.

So What Is Economy-7?

Economy-7 is a tariff provided by energy suppliers which have two-tiered pricing. There are daytime power rates and an off-peak rate which is greatly reduced, of which storage heaters and some forms of hot water heating can utilise to use energy when it is cheaper. 

The main reason why electricity is cheaper as a whole is that in the evenings/early hours there is far less demand for energy, which means power plants that run on more expensive fuels in the day (peak plants) are throttled right down, and the “base” power plants that run on cheaper fuel have enough capacity to supply the demands of the off-peak electricity usage. Storage heaters are usually installed on Economy 7 metering systems. 

The off-peak tariff is usually about half price of the standard tariff. However, energy suppliers often charge more for energy used in the day compared to their standard tariff. 

With Economy-7 you have either one electricity meter with two outlets or two meters. The first meter/part of the meter provides electricity continually, and powers everything other than the storage heaters and usually the hot water immersion. The second meter/part of the meter only allows electricity off-peak, which is usually in the late evening and the early hours of the morning. This allows power to the off-peak appliances through a separate wiring circuit.

How Storage Heaters And Off-Peak Hot Water Works:

Hot water and storage heaters are heated through the off-peak hours and “charge” to store heat. Hot water cylinders typically have a boost function you can use should you need more hot water through the day. This is generally provided by a second immersion on the hot water cylinder.

Storage heaters work by using elements to heat up a series of special bricks which absorb the heat. This heat is then stored in the bricks as it charges them thermally. Heat is released slowly from these bricks as it charges, but the heater will heat the bricks hotter until they are at the required temperature and the Economy-7 circuit has turned off. At the end of this cycle, the storage heaters will release the heat based on your settings, which is often controlled by how much a vent is open on each heater.

Economy-7 – Works Well With Hot Water:

For hot water production, Economy-7 works great! A whole cylinder can be heated up off-peak, when more often than not it is not being used, giving you much cheaper hot water. So long as the hot water cylinder is well insulated, and adequately sized so it does not need to be boosted by heat through the day, you can produce heating for hot water at competitive rates when compared to other off-grid heating solutions. Other off-grid solutions, such as LPG, Oil and some renewable technologies, have hidden costs with maintenance. Immersion heaters can work for many years with no fault, and they are cheap to replace in most instances. 

Storage Heaters Are Rubbish For Heating:

Storage heaters are terrible. Their biggest problem is the need to guess how much heat is needed for the next day and guess the weather. 

A storage heater usually has two adjustable settings, one is the thermostat which controls how much heat is stored in the bricks (how hot they will reach), and the other is the how quickly it releases the heat which is stored. A simple adjustable vent often controls this, and when opened more, it allows for a faster transfer of heat into the room. 

When a storage heater is set to come on next day, and it is too warm for heating, which can happen in spring and autumn especially, most people open windows to cool the room/property and waste the heat they have produced. 

When a storage heater is set too low, and it is cold in the morning, either the home will not get warm enough or will run out of heat prematurely. This often results in the need to use additional heaters 

Another problem with storage heaters is it is common that when they are set to maximum charge temperature and put at the slowest release, rarely they provide heat long enough to warm the property beyond mid-afternoon unless the property is very well insulated. In most cases, people are cold by the evening and need to use another heat source.

Where people work through the day, and no one is at home, storage heaters will be pretty useless to most people unless, as mentioned above, the property is very well insulated.

First-Hand Experience – Use Panel Heaters Instead!

I used to own a property which had storage heaters. The storage heaters were converted to panel heaters which could be used on a 24-hour basis, plus we installed electrically heated towel rails in the bathrooms. The apartment at the time was around 12 years old and had three people living inside, of which two (woman and young child) were at the property most of the time. Everything else, including hot water, ran off electricity. The property only used £770.00 of fuel in the first year (2011), and never had any maintenance costs over the 5-years which the property was owned. The heating was on permanently for most days through winter. 

Panel heaters are very effective. They do not need to be put on a timer as they heat up the space they are in very quickly so long as they are correctly sized for the room. In our option, they are the best overall solution for small homes, such as flats, who do not have mains gas. 

FORTHRIGHT can help you with alternative heating solutions to storage heaters, we offer our services in Cheltenham, Gloucester, Stroud, Tewkesbury and the surrounding areas.