How to run your storage heaters efficiently using Economy 7

[Update: As nuclear and coal stations are wound down in the UK, this could mean the death of the Economy 7 tariff. This would mean storage heaters becoming more expensive to run, and as such we no longer recommend people install new storage heaters. Read our latest advice here under ‘The future of storage heaters’.]

Economy 7 and storage heaters

To make the most of a storage heater, you need to be on an Economy 7 tariff. Unfortunately, a lot of people don’t know how to best utilise this and end up charging their heaters at the wrong time.

The easiest way to understand storage heaters is to visualise them as a big rechargeable battery; they require charging prior to discharging the energy contained within them. With Economy 7 tariffs, the electricity is supplied to your home at two rates: expensive ‘peak-time’ electricity and cheap ‘off-peak’ electricity. The cheapest way to ‘recharge’ the storage heater would be to do so using the cheap ‘off-peak’ electricity, but it just so happens that this is only available during the middle of the night – usually from 12 until 7 in the morning.

If you charge the storage heater during the middle of the day then you will be charged the peak rate and this quickly becomes a very expensive way to heat the home.

Will storage heaters leak heat?

Unlike a battery that will retain a lot of its charge until required, the storage heater will begin to leak heat almost immediately. Obviously the longer the storage heater can retain the heat, the more useful it is, and therefore companies will make you pay more for these products.

As a rule of thumb though, a storage heater will lose the majority of its stored heat over a 12 hour period. This means that if you get in from work at 7pm, the majority of useful heat will already have dissipated into the home – so the storage heater will not provide you with the temperature uplift you would expect from a traditional heating system.

Obviously this can be mitigated to a certain extent by having a really well insulated house, since the heat can’t escape the property. However any solid brick or uninsulated cavity wall home is going to struggle.

How to set up your storage heater controls

Most storage heaters have 2 key controls:

  1. Power switches – this determines whether you are using off-peak on peak electricity to charge the storage heater (remember off-peak is considerably cheaper!)
  2. Input and output controls – the input control determines how much electricity the storage heater will use to charge (and therefore the amount of available heat once the storage heater is charged). The output control controls the rate at which the storage heater emits heat into the room.

In terms of running the storage heaters in the most effective (and cheapest) manner possible, the first thing to ensure is that you don’t use the peak electricity power switch unless absolutely necessary – obviously you don’t want to get cold, but try to avoid using this unless in the middle of the winter when you need a heating boost. The idea is to make sure the storage heater only charges during off-peak hours.

During the winter you will want to set the input control to the maximum – this will allow the most charging power to the storage heater. In the summer you may get away with turning the input control right down (or even off), since you won’t need much heat for the home.

Obviously turning the output control right up will mean that the storage heater does all its heating very early in the morning, so not ideal if you want to be warm in the evenings. If you do get a new storage heater it should retain the heat until mid/late afternoon – it is then that you should turn up the output, so the house warms for when you get home.

Make sure you turn the output to zero when you are not at home or when you go to bed – there is no point releasing the heat as the storage heater charges, since this means that it won’t have any ‘charge’ for when you need it – instead, it will function more as an electric radiator.

Solar PV and Storage Heaters

Some people ask if it is worth running their storage heaters from electricity generated by solar PV. The answer to this is actually not as straightforward as you would think.

Firstly, you generally use more heating during the winter, at a time when your panels are not producing as much electricity as in the summer. Storage heaters require a lot of electricity, and if you had them on all day during the winter, rather than at night, the additional peak rate grid electricity you would need to supplement the solar panels would be prohibitive, unless you had a really big 10kW+ system (40 panels).

Solar PV Optimisers and Storage Heaters

Having said that, there are ways you can make solar and storage heaters work for you. Technology like the Apollo Gem or the Optimmersion work by utilising all the leftover unused energy generated by your solar system that would otherwise go back to the grid.

Typically this is used to heat your water, but there is no reason why you cannot connect this up to your storage heaters. It won’t be enough to meet all your heating needs, and you will still need a charging cycle at night, but you could use it to top up your heating during the day, and ensure that you have some useful heat still left when you get home in the evening.

Installing storage heaters

Need new storage heaters? We have scoured the country for the best tradespeople, so that we can make sure we only recommend those we really trust.

If you would like us to find you a local installer for storage heaters, just fill in the form below and we will be in touch shortly!


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