Storage Heaters: How do they work?

By William Morris

Content editor

A storage heater is a type of electric heater. They are extolled by some as convenient, super-efficient heating systems that can help you achieve zero-emissions home energy consumption. On certain tariffs they could also save you money. But what exactly are they and how do they work? Find out in our complete guide.

How do storage heaters work?

Electric storage heaters work by allowing electricity to flow through some sort of heating element - usually ceramic or clay bricks, as these absorb heat particularly well. This energy is then held until it’s needed, when it can be released to heat your home or office.

Storage heaters are most commonly used to get the best out of time-of-use tariffs, also called Economy 7 tariffs, which allow you to charge your heater during off-peak periods at a discounted rate.

Economy 7 storage heaters

Economy 7 tariffs offer customers two different rates - one for the day and another, cheaper one for a seven-hour period during the night. This is where the 7 comes from in its name - Economy 10 tariffs also exist, but are less common and usually trade off a certain portion of the discount in exchange for the extra three hours.

Storage heaters pair well with these time-of-use tariffs because they can be set to absorb heat during the night when your rate is cheaper and release it during the day. Economy 7 storage heaters, then, could help you save a bundle if you find the right deal and plan your usage out methodically.

Be sure you do plan your usage accordingly, however, as daytime rates on Economy 7 and Economy 10 tariffs can be as expensive and storage heaters in particular use a lot of electricity. Ofgem recommends that customers who choose a time-of-use tariff use at least 40% of their energy during off-peak hours in order to get the most out of their tariff.

Does Economy 7 still exist?Yes, for now there are still both Economy 7 and Economy 10 tariffs available on the UK market. It is true, however, that they are said to be being phased out due to lack of popularity and profitability.

Pros & cons of storage heaters

Here are the benefits and drawbacks of electric storage heaters as we them:

Are storage heaters a good idea?

On balance, we think that storage heaters could benefit customers in several ways, particularly if they’re willing to switch to a new tariff with an off-peak rate for charging them and adapt their energy consumption accordingly. We’re big fans of the environmental benefits of switching from gas heating to electric, which is more easily sourced from renewable energy, and storage heaters are a great way of saving money as you do this.

We must stress again, however, that it’s only a good idea if you’re willing to adapt your usage. Heating your home with electricity can be expensive if you’re not able to charge during off-peak hours, and even more so if you’re on a time-of-use tariff and you charge during peak hours.

How to use storage heaters

Storage heaters are easily managed using an output controller, which allows you to decide how much heat is let out into the room and when. The basic tech behind storage heaters has stayed the same for years, but modern automatic models offer more sophisticated controls than older manual ones.

Among the more sophisticated controls that modern electric storage heaters have today are:

• A thermostat, allowing you to heat the room to the exact temperature you want.
• Intelligent charging, allowing you to store the right amount of heat, rather than the old manual controls to set heat storage.

Some newer models come with digital controllers that allow you to set the temperature of the room like a central heating system, while others can connect to your home’s WiFi and be controlled via your smartphone. Newer storage heaters also have other smart features, such as a sensor that automatically turns off the heat when a window is opened.

How to install a storage heater

With no need to install pipework or a gas boiler, storage heaters can be a lot simpler to fit than gas central heating, and this also makes them cheaper to install. Installation is usually arranged through the company you buy your storage heater from, and the cost of installation will vary depending on how many heaters you buy and how much you spend on each.

You will also need to consider whether your home needs to be rewired in order to facilitate separate peak and off-peak electricity rates. This might also bump up the cost of installation.

How to remove a storage heater

If you’ve moved into a home with storage heaters fitted or have just decided you no longer want to use them, your approach will depend on how the storage heaters have been wired into the property.

If the storage heater has been plugged into a standard plug socket, you can of course just unplug it and take it off the wall yourself. If the heater has been wired in directly, however, you will need to call a qualified electrician in order to remove it and make the wiring safe. When in doubt, we always recommend playing it safe and having an electrician come and take a look.

Storage heater repair

If you think that you need a repair done on your storage heater or heaters, first we recommend checking that you’ve correctly set up the controls on your heater and to make sure that it hasn’t just turned itself off because the window has been opened.

If you’ve done the above and your heater still isn’t working, there are two likelihoods:

1. If none of your heaters are working, it could be a problem with the heating consumer unit. Check for a tripped circuit breaker and, if this doesn’t seem to be the problem, call an electrician to get help.
2. If only one of your heaters isn’t working, it probably needs to be repaired. Check whether it’s under warranty or you have a service contract for it and call their customer service line to get help - if not, you can also call the manufacturer, who could possibly give you a list of electricians to call to get assistance.

We would also recommend always consulting your device’s instruction manual before getting on the phone to anyone, as you may find troubleshooting help specific to your model there.

Should storage heaters be left on all the time?

It’s important to have your storage heaters configured correctly (a job for a qualified electrician) and that their internal clock is set to charge only during your tariff’s off-peak hours. These can vary depending on your provider and where you live. If you don’t, you could end up spending a fortune on heating your home.

You’ll probably want to consider turning off your storage heaters when you go on holiday or during the summer months when you don’t need them. If you go away in winter, however, you might consider keeping them running on a low setting so that your house doesn’t get cold and damp while you’re gone.

Best storage heaters

Finding out which are the best storage heaters is important in terms of how easy your life without a standard boiler will be and how much money you can save. Firstly, we should say that there are three types of storage heaters out there:

1. Automatic: These are the new standard type, replacing the old manual heaters, and can detect the temperature of the room and set themselves.
2. Combination: These allow you to turn up the heat during peak hours if necessary, and so come with slightly more advanced controls to allow you more flexibility.
3. High heat retention: These offer the latest in storage heating technology, with highly-insulated cores and quiet fans to spread the heat around the room more effectively. 

You might want to decide on which of these suits you best before you decide who to buy from. If you’re new to this, you won’t be familiar with the main brands, but we’re here to bring you up to speed. Here’s a list of the best-known manufacturers:

• Dimplex
• Creda
• Elnur
• Fischer
• Heatstore
• Stiebel Eltron
• Vent Axia

What is the best storage heater on the market?

Dimplex is certainly the most popular brand, and its Quantum model has a reputation for being among the best storage heaters on the market. It’s frequently cited as being the most advanced and economical heater available, but that’s not to say it’s the only one worth looking at - to find the best storage heater for your home, we suggest shopping around all the above brands.

Storage heaters cost

In this final section, we’ll take you through how much storage heaters cost to run and answer the all-important question:

Are storage heaters expensive to run?

How much storage heaters cost to run depends mostly on the size of the unit or units you have fitted. According to EDF, a small unit may use about 1kW per hour when absorbing heat, whereas a larger storage heater can use up to 3kW per hour of energy as it charges up.

How much your storage heaters cost will depend on how much heat your room needs - which depends on everything from how big it is relative to the heater to how much you use it. Many heaters now will charge as much as they need and then stop charging automatically.

To give you an idea of what you would spend, however, here are a few pricing estimates for a 7-hour charge based on the cheapest off-peak rate (8p per kWh) and the cheapest peak rate (12p per kWh) for Economy 7 right now:

Those with a knack for quick maths will already have noticed that the monthly cost of heating your home with an electric storage heater can vary from around £16.80 at the cheapest end to £88 or more for off-peak charging with a larger unit - and bear in mind we’ve not even quoted the most expensive tariff.

This should drive home the importance of charging off-peak, as £88 per month before you even consider other appliances like your washing machine, dishwasher and cooking appliances is a hefty sum. If you can get a good off-peak rate and only charge it during these hours then it’s clear that savings can be made.

Looking for ways to save on home energy?Find several handy energy saving tips in our guide - you’ll be amazed at how easy it is to save.