Does a home battery without solar panels pay back

Octopus Energy will install a 10 kWh home battery with no solar panels attached from £5,336, on its April 2026 prices. Charge that battery on Intelligent Octopus Go’s 8p off-peak rate, displace 6 kWh of teatime electricity every evening for 300 days a year, and it returns about £308 a year against the capped 26.11p peak rate. That is a simple payback of roughly 17 years, against a battery warranty that usually runs for 10. Without an electric car you cannot get the 8p rate, and on real Agile prices the same 6 kWh evening returns about £187 a year, which is 28 years. That gap is the whole story of this guide.

Buying electricity cheap at night and using it at teatime is a sound idea. The problem is that in July 2026 the arithmetic for a household without an electric car is tighter than most installer quotes admit. This guide sets out what a standalone grid-charged battery costs, which tariffs you can actually get, how much energy the thing can realistically move in a year, and the four points where the case usually falls apart. Every figure below traces to a named source with the URL attached.

Can a battery pay for itself without solar panels?

Yes, in principle. A battery with no solar panels makes money in one way only: you buy a kWh when electricity is cheap, store it, and use it instead of buying a kWh when electricity is expensive. Your profit is the gap between those two prices, minus the energy lost in the round trip, multiplied by the number of kWh you genuinely shift. Nothing else is going on.

That means three variables decide everything, and none of them is the battery brand:

• The price spread. How much cheaper is your off-peak rate than your peak rate, and can you actually get on a tariff that offers a wide one.
• The volume shifted. How many kWh you would otherwise have bought at the expensive rate, on a typical day, in a typical week of the year.
• The capital cost. What you paid, divided by how many years the kit and the company behind it survive.

For context on the price you are arbitraging against, Ofgem’s cap for 1 July to 30 September 2026 sets the direct debit electricity unit rate at 26.11p per kWh with a 57.19p daily standing charge, averaged across England, Scotland and Wales and including 5% VAT. That standing charge costs £208.74 a year whatever you do, and a battery does not touch it. Gas sits at 7.33p per kWh and 29.04p a day, and a battery does not touch that either. Ofgem’s wording on the increase is precise and worth repeating properly: “energy prices will go up by 13% for a typical household who use electricity and gas and pay by Direct Debit”. That is a dual-fuel bill figure, not a statement that the electricity unit rate rose 13%.

Why the government’s £300 figure does not describe this house

You will see one number quoted in almost every battery sales conversation, and it is being used wrongly. The Department for Energy Security and Net Zero (DESNZ) says in its Warm Homes Plan that households who “switch to a time-of-use tariff and set up their battery to charge during off-peak hours could save up to an additional £300” a year.

The word doing the work is additional. Read the sentence before it on the same page. According to DESNZ, households that adopt a heat pump, solar photovoltaic (PV) panels and a battery could save up to £550 a year on their energy bill. The £300 is the extra on top of that. It belongs to a house that already has a heat pump, already has solar panels, and already has a battery. This guide is about a house with none of the first two.

The technical annex makes the mismatch explicit. DESNZ assumed savings “consistent with a 10% reduction in the unit rate for electricity, based on a review of evidence of time of use tariffs in relation to heat pumps and adjusting for the role of other demand shifting technologies in shifting electricity to lower price periods”. The evidence base is heat pumps. The modelled property carries “4 kW of PV panels” and a battery “equivalent to 4 kWh of storage”, on an assumed day of “8 hours of electricity at off-peak rate, 13 hours at standard rate and 3 hours at peak rate”.

Reverse the government figures and the problem is obvious. A house with a heat pump and solar panels draws far more electricity than a gas-heated house with neither, and it has far more of that draw sitting inside hours a battery can shift. Strip out the heat pump and the panels and you have removed most of the load the £300 was calculated against.

The annex is also blunt about what you may not do with its numbers: “Combining or aggregating estimates on bill savings would lead to misinterpretation and therefore all figures should be considered independently.” That rules out the obvious shortcut of taking DESNZ’s 10% unit-rate haircut and multiplying it by Ofgem’s typical consumption values, because those two figures come from different models built for different purposes. This guide does not do it.

So there is no published government figure for a grid-charged battery in a home with no solar panels and no heat pump. Everything below is built from stated inputs instead, and every input is on the table so you can swap in your own.

The tariff trap, and why the cheapest off-peak rates need an electric car

This is the point most articles skip, and it is the one that changes the answer for a large share of readers.

The headline cheap overnight rates people quote at each other are gated on EV ownership. Octopus Go lists “have an electric car that you charge at home” as a requirement, with an off-peak window of 00:30 to 05:30. You do not need a home charge point, but you do need the car. Intelligent Octopus Go, with its 8p per kWh off-peak rate across six whole-home hours between 23:30 and 05:30, requires a compatible EV or charger linked through the Octopus app plus a smart meter, and the rate varies by region.

If you have no electric car, those doors are shut. Octopus itself points battery-only customers at Agile Octopus instead. Agile needs no EV, but it works differently in a way that matters:

• Prices are updated between 4pm and 8pm every day for the following 24 hours, based on wholesale market rates. There is no fixed off-peak rate you can build a spreadsheet around.
• Peak pricing typically lands between 4pm and 7pm, which is precisely when your battery is discharging.
• Agile prices “can spike up to 100 p/kWh any time”, with a guarantee that you “never pay more than 100p / kWh”. That cap is nearly four times the Ofgem capped rate.
• You need a compatible SMETS2 smart meter, or certain first-generation SMETS1 meters, and around 14 days for the half-hourly connection.

The non-smart alternative is Economy 7. Ofgem’s consumer guide explains that the cheap period “usually runs from midnight to 7am, but it may vary depending on your location and your supplier”, and that you pay “one rate for electricity used during a specified off-peak period, and another, more expensive rate during peak hours”. Ofgem adds the warning that matters here: “If you don’t use much electricity at night, then you’re likely to be better off on a single rate tariff.”

How much more expensive is that day rate? Ofgem does not publish a figure. Its price cap unit rates page says only that “for multi-rate tariffs like Economy 7 you will pay one unit rate during peak hours and a different unit rate during off-peak hours. Together, they cannot be more than the price cap.” The split between the two is set by your supplier and your region, so you have to ring them and get both numbers before any of this arithmetic means anything. There is a break-even test further down that tells you what to do with the pair once you have it.

What a standalone battery actually costs in 2026

Octopus publishes battery-only prices, which is rare and useful. Which? gives the wider market range and lists prices from several named suppliers: “battery storage costs can range from less than £2,000 up to £10,000 depending on battery capacity, type, brand and lifespan.” Note the floor. It is below £2,000, not at it.

Every price in the table is a “from” price. None of them is a quote for your house.

Two things are worth pulling out. First, in the Octopus range the 5 kWh unit is the worst value at £789 per kWh against £534 at 10 kWh, because a large slice of the cost is the inverter, the labour and the paperwork rather than the cells. Second, Which? words the Scottish Power entry as batteries “from £2,910 (or £1,680 if you buy them with solar panels)”. Which? does not say those two prices are for the same battery, and it does not describe the £2,910 as a standalone-only rate, so do not read a measured premium into the difference. Read it as a prompt to ask any supplier for both prices in writing and to check the model number on each.

Octopus also asks for a £500 advance payment on signing, and states that battery installation is subject to approval from your Distribution Network Operator (DNO), the company that owns the cables in your street. More on that below.

Sizing to your evening block, not your annual consumption

Here is the arithmetic that kills most optimistic payback claims, and it takes 30 seconds.

Ofgem revised its Typical Domestic Consumption Values on 1 July 2026, and revised them down. In its May 2026 decision, medium single-rate household electricity fell from 2,700 to 2,500 kWh a year. Medium multi-rate electricity, which is the profile class Economy 7 and most time-of-use customers sit in, fell from 3,900 to 3,400 kWh a year. Medium gas fell from 11,500 to 9,500 kWh.

Now take a 10 kWh battery and cycle it once a day, fully, every day. That moves 3,650 kWh a year. A typical multi-rate household uses 3,400 kWh in total, including everything it draws overnight at the cheap rate anyway. The battery would have to shift more electricity than the house consumes. Any quote or online calculator built on 365 full cycles is arithmetically impossible for an average home, and you should treat the rest of that document with suspicion.

The number that matters is your evening block: the kWh you draw between roughly 4pm and 10pm, when the cooker, the kettle, the telly, the washing machine and the lights are all running and the tariff is at its most expensive. For most homes that is somewhere in the range of 4 to 8 kWh. Size to that, and accept that on many summer evenings you will not empty the battery at all.

A practical sizing method:

1. Log into your smart meter app or your supplier’s half-hourly data and pull a week of readings in January and a week in June.
2. Add up the kWh consumed between 16:00 and 22:00 for each day.
3. Take the median winter figure, not the peak. That is the capacity that will be used most nights.
4. Add roughly 12% on top for round-trip losses, covered next.
5. Ignore your annual total entirely. It tells you nothing about what a battery can displace.

Round-trip losses, and why 11% and 12% are the same number

Electricity does not survive a round trip through a battery intact. The Tesla Powerwall 3 datasheet states a “Solar to Battery to Home/Grid Efficiency” of 89%. Roughly one kWh in nine disappears as heat between the meter and the socket.

Those two percentages you keep seeing are one fact stated from opposite ends. Lose 11% of what you buy and you keep 89%. To end up with 6 kWh at the socket you therefore have to buy 6 ÷ 0.89, which is 6.74 kWh, and that is 12% more than 6. So 11% is the share of purchased energy lost, and 12% is the top-up you add to a delivery target. Same physics, two different starting points.

There is a bigger caveat on that 89%, and it is the one nobody quotes. Tesla footnotes the figure “typical solar shifting use case”, and the label on the row is “Solar to Battery to Home/Grid”. It describes energy arriving from solar panels as DC and going into a DC-coupled battery. A grid-charged battery is a different path: mains AC has to be converted to DC before it reaches the cells, a step the solar route skips. Tesla publishes no grid-to-battery-to-home figure at all. The nearest comparison on the same datasheet is “Solar to Home/Grid Efficiency” at 97.5%, which is the panels-straight-to-house path with no battery in it.

Treat 89% as a ceiling borrowed from the wrong charging mode, then. The datasheet’s own conditions narrow it further: values are “provided for 25°C (77°F), at beginning of life. 3.3 kW charge/discharge power.” Beginning of life, so it degrades. A 3.3 kW charge rate, while the same unit can be configured up to 5 kW charge and 11.04 kW discharge. And Tesla states performance “may be de-rated at operating temperatures above 40°C” within an operating range of −20°C to 50°C. Every payback figure below uses 89% anyway, which flatters the battery. Real grid round-trip efficiency will be lower, and Tesla has not told anyone by how much.

An illustrative payback calculation, with the assumptions on the table

The following is an illustrative calculation, not a customer case study. Every input is stated so you can substitute your own.

Assumptions: a 10 kWh battery installed for £5,336 at 0% VAT (Octopus, April 2026 prices). Avoided peak rate of 26.11p per kWh, the Ofgem capped direct debit rate for July to September 2026. Off-peak charging at 8p per kWh, the Intelligent Octopus Go rate, which requires an electric car. Round-trip efficiency of 89%. No solar panels. No degradation, no maintenance and no finance cost.

Look at the bottom row before you get excited by it. Displacing 8 kWh every single day for 365 days means moving 2,920 kWh a year at peak rates. A typical multi-rate household consumes 3,400 kWh in total, so 86% of everything the house uses in a year would have to fall inside the evening peak window. That does not happen in a real home. The realistic rows sit between 13 and 26 years, and every one of them needs an electric car on the drive before the 8p rate is available at all.

The same sums for a household with no electric car

This is the reader the whole guide is aimed at, so here are real numbers rather than a shrug.

Octopus publishes live Agile unit rates through its public tariff feed, so you can check this rather than take my word for it. In the data from that feed for 21 July 2026 in the London region, the ten half-hours between midnight and 05:00 ranged from 20.20p to 23.40p per kWh, averaging about 22p. The four half-hours from 16:00 to 18:00 ran 31.89p, 33.71p, 36.82p and 38.12p, averaging 35.1p. The day before, the 17:30 half-hour reached 41.86p.

So the working spread on that day was roughly 22p in and 35.1p out. After the 89% round trip, every kWh delivered to the house nets 35.1p minus 22p ÷ 0.89, which is 10.4p. Compare that with 17.1p on Intelligent Octopus Go. The Agile spread is 39% narrower, and it is narrower because you are no longer buying at a subsidised EV rate, you are buying at whatever the wholesale market did overnight.

Two honest caveats on that table. It uses a single summer day in a single Agile pricing region, and July wholesale prices are not January wholesale prices. Agile rates vary by region, so yours will differ. Winter widens the peak and usually widens the spread, so a winter sample would produce a better answer. Run the same sums on your own region’s feed across a January week before you commit to anything.

The second caveat cuts the other way, and it corrects something usually asserted without evidence. Time-of-use tariffs are supposed to punish you with a higher daytime rate. On 21 July, Agile’s mean across all 48 half-hours was 23.59p against the capped 26.11p, and only 7 of the 48 periods went above the cap at all, with the cheapest half-hour at 18.54p in the early afternoon. On that day, Agile beat the price cap outright before the battery did anything. The daytime penalty is real on some days and absent on others, which is exactly why a fixed spread cannot be assumed.

The break-even test to run on any tariff

You can settle this for your own quote and your own tariff pair in one line. To recover £5,336 inside the standard 10-year warranty, at 6 kWh displaced on 300 evenings a year, you need £533.60 a year from 1,800 kWh delivered. That is 29.6p of net gain per kWh delivered.

So the peak rate you avoid has to clear 29.6p plus your off-peak rate divided by 0.89:

• At an 8p off-peak rate, your peak rate must reach 38.6p, which is 48% above the current 26.11p cap.
• At a 22p off-peak rate, your peak rate must reach 54.4p, which is more than double the cap.
• Push utilisation to 8 kWh on all 365 days and the requirement falls to 18.3p of net gain per kWh, so an 8p off-peak rate needs only a 27.3p peak. That is the single realistic-looking combination, and it demands the peak window absorb 86% of your annual electricity.

Take the two rates your supplier quotes, put them into that line, and you will know in ten seconds whether a salesperson’s payback figure is possible.

What happens if peak prices keep rising

The strongest argument for a battery is that the gap it exploits gets wider over time, so the fair thing is to price that in. Ofgem’s cap rose 13% this quarter for a typical dual-fuel direct debit household. As an illustration only, apply that same 13% to the electricity unit rate and it goes from 26.11p to 29.50p. The 6 kWh, 300-day Intelligent Octopus Go row then improves from £308 to £369 a year, and payback falls from 17.3 years to 14.4.

Better, and still not inside the warranty. A single 13% step does not rescue the case. It would take something closer to a 48% rise in the peak rate, at a fixed 8p off-peak rate, to bring that row inside 10 years.

Degradation, replacement, and the number that closes the argument

Every payback row above assumes the battery holds its capacity forever. It does not. Tesla’s 13.5 kWh and 89% are both quoted “at beginning of life”, and Which? warns that “usable capacity is usually less than stated capacity”, because “batteries tend to lose some energy in charging and discharging, and most aren’t designed to be fully discharged on a regular basis”.

You do not need a degradation curve to see where this ends. Which? tells buyers that “solar PV panels can last 25 years or more, so you should factor in the cost of replacing the battery at least once into your total costs”, and that “battery systems often come with a 10-year warranty”. Line that up against the tables. Only one row in either table pays back inside 10 years, and it is the physically impossible one.

Follow it through on the 6 kWh Agile row at 28.5 years. Somewhere around year 12 you buy a second battery. Call it another £5,336 and the capital line has doubled while about £2,250 of gain has accumulated. On that path the payback never arrives, because you keep buying the asset faster than it repays you. A 28-year row against a 10-year warranty is not a slow win. It is a loss with a longer settling period.

VAT is 0% until 31 March 2027, and the mistake that costs you 20%

The tax position is better than most people think, and worse than most people think, in two different places.

HMRC’s VAT Notice 708/6 on gov.uk confirms that “the installation of a standalone battery for storing electricity from the grid (the mains electricity)” qualifies for the zero rate, in force from 1 February 2024. You do not need solar panels to get 0% VAT on a battery. That is the good news, and plenty of installers still get it wrong.

The relief runs to 31 March 2027. The bad news usually attached to that date is wrong. Section 1.1 of the notice states that “from 1 April 2027 onwards, supplies of installations of energy-saving materials will revert to the reduced rate of VAT of 5%.” It reverts to 5%, not 20%. On a £5,336 battery that is roughly £267 of extra tax, not £1,067. If an installer is pressing you to sign before March 2027 to dodge a £1,000 VAT bill, the premise of that sales pitch is false.

The genuinely expensive mistake is a different one. HMRC is explicit: “however, if you supply energy-saving materials without installing them your supply will be standard-rated.” Buy the battery online and get a local electrician to fit it and you pay 20% VAT on the hardware. On a £4,000 battery that is £800 of tax you did not need to pay, which will usually swallow whatever you saved on labour. The relief only exists where the person installing the battery also supplies it.

Warranties and the GivEnergy lesson

Most home batteries carry a 10-year warranty. Tesla attaches a condition worth reading: the Powerwall 3 “must be reliably connected to the internet to secure the full 10-year warranty”. A router change, a house move, a broadband outage that nobody notices for six months, and you may have a conversation on your hands.

The bigger issue is who is standing behind the promise. On 9 April 2026, GivEnergy Ltd entered administration, with Chris Brooksbank of CB Business Recovery appointed as administrator. The Energy Storage Association (UK) describes the scale of it plainly: “GivEnergy is the largest domestic battery manufacturer to stop trading to date.” It is equally plain about what that does to owners: “GivEnergy warranties can only be enforced against GivEnergy itself and their closure likely means you will be unable to claim against those warranties in the future.” The administrator was not appointed over every entity in the group, including GivEnergy Software Limited, and owners are directed to approach their installing company first. Anyone who paid by credit card may have rights under Section 75 of the Consumer Credit Act 1974.

A failure on that scale reflects how young this market still is. DESNZ counts MCS-accredited domestic battery installations and records that by March 2025 there were “more than 28 000 installations”, up “from less than 1000 installations in September 2023”. That is an industry two years into rapid growth, with the shakeout still ahead of it. Practical protections:

• Pay the deposit, or as much of the balance as you can, by credit card, so Section 75 applies to purchases over £100.
• Ask who honours the warranty if the manufacturer fails, and get the answer in writing on the quote.
• Prefer an installer who has traded for years locally over a national brand you found in a search ad. Your first claim goes to the installer.
• Treat a 10-year warranty against a 17-year payback as the real risk, because the numbers only work if the kit outlives the guarantee by a wide margin.

Why you cannot sell stored grid electricity back at peak

A popular idea online: charge at 8p overnight, export at the 4pm to 7pm peak, collect the difference. Ofgem has closed this off.

The Smart Export Guarantee (SEG) is the scheme that pays households for electricity exported to the grid. Its eligible technologies are solar PV, wind, micro combined heat and power, hydro and anaerobic digestion, up to 5MW total installed capacity, and the installation must be “located in Great Britain”. A battery is not on that list, because a battery generates nothing.

Ofgem’s SEG guidance for generators deals with the battery case directly. Paragraph 1.39 states that “where the export meter for an eligible installation also records electricity exported from a non-SEG eligible source, a SEG licensee is not obliged to make SEG payments, but they can if they wish.” Paragraph 1.40 names the exact scenario: “an export meter may record export from a non-SEG eligible technology, a standby generator or a battery that is charged from a source other than the SEG eligible technology.” Paragraph 1.41 allows the licensee to demand additional metering or to pro-rate the payment instead.

Some suppliers do run commercial export or flexibility schemes on their own terms outside SEG, and those can be worth having. The point is that nobody is obliged to pay you for exporting stored grid electricity, so do not put an export income line in your payback calculation and treat it as guaranteed.

Getting it signed off, and how the rules differ across the UK

A battery is a generator as far as the network is concerned, and it needs permission. The threshold is set by the inverter rating, not the battery capacity, which catches people out.

National Grid’s G98 procedure covers “micro-generating plant with an aggregate registered capacity of 16A (3.68kW) per phase or less”, and it is a notify-afterwards route: “once the generation is commissioned you must fill in and return a G98 Installation Document along with an Operation Diagram within 28 days.” Above that line you are into G99, which National Grid applies to “installations that are either rated above 16A (3.68kW) per phase or that do not meet the requirements of the current version the Energy Networks Association (ENA) Engineering Recommendation G98”. G99 runs as an application and connection offer process with a separate post-acceptance stage, so the paperwork sits ahead of the job rather than behind it. A 5 kW inverter on a 10 kWh battery is a G99 job. Octopus states that its installations are subject to DNO approval, so a refusal or a constrained approval on a weak network is a real possibility.

Fire safety has its own standard. BSI published PAS 63100:2024, “Electrical installations. Protection against fire of battery energy storage systems for use in dwellings. Specification”, on 20 March 2024. It covers battery and fault management and permitted installation locations, references BS 7671, and its provisions are “intended to reduce the risk of batteries in dwellings becoming a source of ignition, and to limit the impact of a battery fire if one occurs.” Ask any quoting installer whether they work to PAS 63100:2024 and where they intend to site the unit. If the answer is vague, get another quote.

Where the four nations diverge:

• England, Scotland and Wales. Ofgem’s price cap figures above are averages across these three nations, and the SEG applies across Great Britain.
• Northern Ireland. Ofgem’s cap does not apply, and the SEG does not extend there. The G98 and G99 framework quoted above is the Great Britain distribution route, so NI homeowners should confirm the connection process with their own network operator before ordering anything.
• Scotland and Wales. The 0% VAT relief is a UK-wide tax measure and applies identically, since VAT is not devolved.
• Funding. DESNZ’s Warm Homes Plan commits “up to £1.7 billion of the facility to new low- and zero-interest consumer loans” covering solar panels and batteries, to roll out “in phases, expanding over time”, with eligibility detail still to come. It is a loan scheme for most owner-occupiers, not a grant. Direct capital grant support for low-income households is put at over £4.4 billion by 2030. The £5 billion figure you may see quoted attaches to the Warm Homes Fund, which DESNZ describes as financial transactions available for deployment across various mechanisms, so treat it as a different thing from grant money. Devolved administrations run their own schemes, so check the position for your nation rather than assuming an England announcement applies to you.

Four claims worth pushing back on

1. “0% VAT ends in 2027 and jumps to 20%.” HMRC section 1.1 says 5%. About £267 on a £5,336 battery, not £1,067.
2. “Just get Intelligent Octopus Go at 8p.” Both Go and Intelligent Go require an electric car.
3. “The government says you’ll save £300 a year.” That figure is additional to a heat pump plus solar plus battery package, and its evidence base is heat pumps.
4. “There is no planning permission, so there is no paperwork.” A G98 notification within 28 days of commissioning or a G99 application before the job, plus PAS 63100:2024 fire safety, plus DNO sign-off.

Who a standalone battery genuinely suits, and who should wait

On the verified numbers, a grid-charged battery with no solar panels is a poor purchase for an average UK household in 2026 and a marginal one at best. It makes better sense in four situations:

• You already own an electric car. You can access an 8p off-peak rate, the spread is 39% wider than Agile’s, and the battery rides on tariff access you already have. This is the strongest case by a distance.
• Your evening consumption is genuinely high. An all-electric home, electric heating, or a household at home from 4pm every day pushes you toward the 8 kWh rows of both tables.
• You are adding solar within two years. Free daytime generation changes the input cost from 8p or 22p to nothing, and Which? shows Scottish Power quoting £1,680 for a battery bought with panels against £2,910 on its own.
• You value backup power for its own sake. If you are on a rural network with frequent cuts, or someone in the house depends on mains-powered medical equipment, resilience has a value no payback table captures. Confirm with the installer that the system actually provides backup, because many do not without extra hardware.

Wait, or spend the money elsewhere, if you have no EV, an average evening load, and a salesperson quoting a payback under 10 years. At Ofgem’s revised 9,500 kWh typical gas consumption and 7.33p per kWh, a typical household spends about £696 a year on gas plus £106 in standing charges. Insulation and heating controls attack that bill directly, and generally at a fraction of £5,336.

What to do, and by when

1. This week. Run the seven-day sizing exercise above on your own half-hourly data. If your median winter evening block is under about 6 kWh, you can stop here and save yourself the quotes.
2. Before you request quotes. Ring your supplier and get the two actual unit rates you would be charged, off-peak and peak, for your postcode. If you have no electric car, pull a January week from your region’s Agile feed rather than trusting a summer average or the 8p headline.
3. The moment you have those two rates. Run the break-even line: your peak rate must clear 29.6p plus your off-peak rate divided by 0.89 for a £5,336 battery to repay inside its warranty. Most tariff pairs will fail it.
4. At quote stage. Insist on a battery-only price, the inverter rating, whether it is a G98 or G99 job, confirmation the installer works to PAS 63100:2024, and a written answer on who honours the warranty if the manufacturer fails.
5. Before 31 March 2027. The 0% VAT window closes and the rate goes to 5%, worth about £267 on a £5,336 install. That is a reason to be organised, not a reason to rush.
6. Reject any quote whose savings assume daily full cycling, or an export income from selling stored grid electricity, or a saving that fails the break-even line above.

If you have an electric car and a heavy evening load, run these numbers on your own tariff and the case may well clear. If you do not, it has not arrived yet.