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Home batteries: are they the next big thing?

home battery

They claim to save you hundreds of pounds on your electricity bill, help you towards electricity self-sufficiency, and even let you play a part in the National Grid. Are you tempted by a home battery?

Energy storage systems – also known as batteries – store electricity in your home so you can use it when you need it. Usually this is electricity generated by a renewable system, such as solar PV or a wind turbine, but you can also store electricity from the grid.

And it looks as though batteries are moving into the mainstream.

Eon launched its solar and storage offering last month and it claims that installing a battery can help you use 30% more of the electricity you generate than with solar panels alone. Combined, it says you could make £560 a year in savings and earnings.

This week, Nissan also announced it’ll be selling home batteries – customers can choose a battery previously used in an electric car, or the pricier option of buying brand new.

And Tesla, which is more famous for its cars, sells a home battery it claims can power the average two-bedroom house for a day.

It’s early days yet for home battery storage but, with over 900,000 solar PV installations in the UK, its potential to grow is huge.

Battery storage benefits

If you have solar PV, wind or hydro turbine, it may generate most electricity when you’re not at home to use it. Unused electricity is exported to the grid and you’ll probably import electricity in the evenings.

Batteries store excess renewable electricity so you can use more of what you generate and help cut your electricity bills. They range from around 1kWh to 8kWh, which the Energy Saving Trust says is enough energy to boil your kettle between 10 and 70 times.

There’s also the potential, with time-of-use tariffs, to charge your battery from the grid when electricity is cheaper, and use up your store at times of day when electricity is more expensive.

Consumer concerns

Solar PV has the Feed-in Tariff, and heat pumps, solar thermal and biomass boilers are supported by the Renewable Heat Incentive, but there are currently no government incentives for home batteries.

So how much money you could save depends on the system you have installed and how it’s used. Many technologies are too new for there to be independent data to estimate typical savings yet.

Battery storage isn’t regulated either, although the Renewable Energy Consumer Code (RECC) was recently extended to include battery storage systems. Installers signed up to the code agree to abide by high consumer protection standards. RECC said that it has seen ‘increased interest in these products’, but also ‘a rise in complaints citing mis-selling’.

We’ve heard from Which? members with battery systems who have very different views on them. One told us about reducing their energy bill to less than £20 per month, while others have complained about systems not working as expected and installation problems. Some found the cost off-putting.

So, do you have a home battery installed? How do you use it and what do you think of it? Is there anything you wish you’d known in advance?


Sadly not enough information to take a view on this . I hope Which? will be monitoring and reporting on this growth area. However without any prices quoted and payback it is hard to say much more.

This should help readers get an overall view :


A little more investigative reporting would not have gone amiss here instead of just copying info straight from the Energy Saving Trust website.

I have found 14kWh batteries in size and 2 of these claim to be sufficient to power a 3 bedroom home for a day.


We need, for example, cost and life of batteries, cost of installation and maintenance, capacity loss over time, conversion efficiency of electricity into battery storage and of battery energy into usable ac, then we can begin to assess whether they are an economic proposition, or when they might be.

Energy saving is more important than energy storage in my view – unless your house is already very efficient. It would be useful to review, factually and economically, all the energy saving measures sensible for householders – solar hot water, heat pumps, insulation, glazing, lighting. If you have solar power (wind and hydro – how many have those?) then rather than use all of it yourselves you can export more.

And if it is about saving money and oil, look to your choice of car.


An interesting concept though quite a technical one. Battery storage, a charging device and wiring into the house all need to be sorted, so the capital outlay would probably be a couple of years before it was paid for. Not all buildings are suitable for solar panels and windmills need planning permission. I would like to see research into fuel cells, so that renewable energy could be used to create things like water hydrolysis and this, in turn used to power the house. There are many schemes that use natural energy and heat re-capture. These are most useful when designed into a new building rather than added on, but there is also a danger of environmental problems when a house is turned into an insulated capsule. It’s a new and exciting science -something to be encouraged.


We’ve had solar panels for around 6 years and with a 4kwh array have found them well worth while – but only because of the FIT payments! The actual saving on our electricity use alone would take forever to repay the cost of installation. I have investigated battery back up several times but, as already stated, there is insufficient reliable and independent information available to warrant the cost of installing a battery, both from the technical side and the financial aspect. Sales people just cannot be trusted I have found.


The Introduction refers to a Which? member “reducing their energy bill to less than £20 per month“. . . . . Yes, quite.

Unless we know a lot more about the size of the household, type of property, location [Channel Islands?], lifestyle [TV, computers], whether gas or other fuels are involved, what fuel is used for cooking, heating and hot water, this is a completely meaningless statement that helps no one. Even a rough “before” cost would have been appreciated.


None of them is going to compete with the ultimate cost effective means used by our departed friend in NI — hydro power even has a downward flowing stream . Batteries are an ongoing development I get multiple emails from tech websites detailing the latest US “innovation ” in battery design followed by Japan , you even have “organic ” batteries of various descriptions all spurred on by the US / Japanese car industry . I remember when repairing UK fork lift trucks ( Lansing Bagnall etc ) the massive batteries that powered them and the massive amounts of electricity to charge them. so I will ask the relevant engineering question -has the “perpetual” generator been designed where the efficiency is –100 % ? if not until the “Power of the Universe ” has been harnessed as quoted many times as the type of energy used by “flying saucers ” ( yes it does exist –the power I mean) then there is always a cost for the use of energy in this world even if it is only in the maintenance aspect . Do solar panels “live forever ” nope , is there a pocket size nuke power station with NO radiation -nope, although the Russians are getting close. But , if you are American you must know full well self generation ( household ) is banned by US government legislation because of lobbying by US Big Utilities as well as water storage -YES rainfall banned as well even from your own roof. As you know what happens in the US happens here tomorrow , not something to look forward to –is it ? Now where is that ion drive I have been working on ?


Thought as much guess who is heavily promoting this ?? that US Giant Telsa — its all really commercialism –isnt it ? Well we might as well get some extra money back from our investment in battery run automobiles design , why not be honest ?


Early adopters of PV solar panels are benefiting from a favourable feed-in tariff. Each cut-back in the FIT has, understandably, reduced the appeal of solar electricity generation but it remains economically worth while because the capital cost of installation has fallen considerably. I would doubt that in ordinary situations with solar power the extra outlay for a battery installation would repay itself in a reasonable period. In a home without any renewable electricity intake I cannot see it ever being viable; we need to keep a close eye on the marketing to make sure people are not being swindled into paying for something that will do them no good.

I am sure that domestic solar power installations will continue to grow in number but the rate of expansion might now slow down. I am ever the optimist so I would expect the raw cost of electricity to start declining in real terms as the renewable content of our supplies continues to increase as the huge new off-shore wind-farms start to come on stream and the extensive commercial solar panel arrays start to ramp up their output. Indeed, there have been days lately when the UK was running on the sun and wind alone and actually receiving too much energy from renewables. This trend, if confirmed, could affect the economics of domestic installations so I think we should be cautious about battery storage systems.

I go along with Malcolm and feel that there is more mileage in energy conservation and reduction through practical measures that will help most households and improve the condition of our housing stock at the same time.


I agree with the cautious approach and doing what you can for the housing stock.

Fortunately I am about to start with a clean slate and needing to replace a 20 year old oil heater have been looking at all the options. This goes from wood-pellet to air and ground pumps by way of solar arrays. Or even another oil burner! or just electric.

The decision so far is to make one area heavily insulated and double glazed and leave the balance of the house for warmer weather days. So basically maximise one part for cold weather and being smaller than the whole is intrinsically cheaper to heat. Whether this approach works in the UK where houses are generally small is moot.

I would consider large batteries if the cost is right as I have room for PV panels aswell as panels for heating water.

However for the big problem I wish Which? would get onboard with energiesprong.uk and help drive that in the UK by publicising the considerable benefits and low costs.
” The deceptively simple idea behind the initiative has been to finance the roughly 300,000 mass-produced renovations from the estimated €6bn of savings from energy bills that they will make each year.
In the Netherlands, upfront capital comes from the WSW social bank, which has provided €6bn to underwrite government-backed 40-year loans to housing associations. These then charge tenants the same amount they had previously paid for rent and energy bills together, until the debt is repaid.
The prefabricated refurbishments come with a 40-year builders’ guarantee that covers the entire loan period, and a 5.25% return is guaranteed to participating housing associations.”
Guardian Today: the headlines, the analysis, the debate – sent direct to you

This report touches on one of the main problems for homeowners and that is getting honest and unbiased advice on what to do. The other problem is the consequent servicing.

This covers that dreaded question of how air-tight should one be. I am a fan of heat-exchanging ventilation that doe not seem to feature in this work:



In passing it knows that electric cars have substantial battery storage capacity. I recall that a year or two ago the auto industry was suggesting electric cars with the ability to provide energy back to a house if required. Sounds good doesn’t it.


It’s high time that all new buildings were built with a solar roof and oriented to make best use of the sun. Add-on solar panels are not exactly attractive. When I moved home last year I bought a house with the rear of the roof facing the right direction, so that panels would not be seen from the front. Unfortunately, not a single house nearby has solar panels. We are outside the local conservation area, but maybe there are local rules.

Since 1980 I have spent time living off-grid when on holiday, dependent on batteries overnight, and charged during the day. I first met solar panels in the early 90s when they were extremely expensive and less efficient than they are today. Solar panels are silent and once installed there is no running cost, unlike using a generator.

Knowing that you are dependent on limited battery capacity encourages conservation of electricity and this awareness has helped me become a low energy user when living in my home. If you are not using electricity for any heating other than brief use of a microwave oven and you have low energy lighting and no wasteful electrical products like plasma TVs, modest battery capacity is adequate to be independent of mains electricity for most of the year.

I’m interested in solar power and battery storage and will try to find out why none of my neighbours has solar panels.