Here is the short version: a 4kW solar system costs roughly £5,500 to £8,500 installed in 2026, generates around 3,400 kWh a year in most of England, and pays for itself in roughly 9 to 13 years depending on where you live, how much electricity you use during daylight hours, and which export tariff you sign up to.
That last factor matters far more than most people realise. Two identical systems on two identical roofs can differ by over £200 a year in income purely because of which supplier pays for the exported electricity. We will come back to that.
This guide gives you the actual numbers — installation costs by system size, a worked payback calculation you can adapt to your own bills, current export rates, which grants still exist and when they close, and the specific questions that separate a fair quote from an expensive one.
Key figures at a glance
- 4kW system: £5,500–£8,500 installed. Government MCS data put the average at about £1,785 per kW for 4–10kW systems as of June 2026, which works out at roughly £7,140 for 4kW.
- Adding a battery: a further £3,000–£8,000. Complete solar-plus-battery packages typically land between £9,000 and £14,000.
- VAT: 0% on residential solar and battery installations until 31 March 2027.
- Electricity price: 26.32p per kWh under Ofgem’s price cap for 1 October to 31 December 2026, with a standing charge of 54.83p a day.
- Export income (SEG): anywhere from about 3p to 25p per kWh depending on supplier and conditions.
- ECO4 grant scheme: closes 31 December 2026. No ECO5 is planned.
How much do solar panels actually cost in 2026?
Solar has become meaningfully cheaper. Panel and inverter prices have fallen, and the zero VAT rating removes a fifth of the bill that homeowners were paying before April 2022.
Here is what the market looks like right now for MCS-certified installations. These prices should include panels, inverter, mounting hardware, scaffolding, electrical work, DNO notification and commissioning.
| System size | Panels (approx.) | Roof space needed | Typical annual output | Installed cost |
|---|---|---|---|---|
| 3kW | 7–9 | 11–16 m² | ~2,550 kWh | £5,000–£6,500 |
| 4kW (most common) | 8–14 | 13–22 m² | ~3,400 kWh | £5,500–£8,500 |
| 6kW | 13–18 | 22–32 m² | ~5,100 kWh | £8,500–£11,000 |
| 4kW + 5kWh battery | 8–14 | 13–22 m² | ~3,400 kWh | £9,000–£12,000 |
| 8kW + battery | 18–24 | 30–42 m² | ~6,800 kWh | £13,500–£17,500 |
Why quotes for the same system vary by thousands
A 4kW system is not one product. The spread between a £5,500 quote and an £8,500 quote usually comes down to specific, checkable things:
- Panel tier. Established manufacturers such as Trina, JA Solar, Longi or REC typically carry 25-year linear performance warranties. Budget panels can save £300–£650 up front but often come with 10–15 year cover.
- Inverter type. A basic string inverter is cheapest. A hybrid inverter (battery-ready) costs more but saves you replacing it later. Micro-inverters or optimisers cost more again, and are genuinely worth it if any part of your roof is shaded.
- Roof complexity. A simple south-facing pitched roof is quick. Multiple orientations, slate, a three-storey terrace or awkward scaffolding access all add cost.
- Scaffolding. Usually £750–£1,800, and it should be itemised. If your quote does not mention it, ask whether it is included.
- Battery size and brand. The single biggest variable. A 5kWh unit and a 13.5kWh Tesla Powerwall are not comparable line items.
What will you actually save? A worked example
This is where most solar articles go vague. So let us do the arithmetic properly, using figures you can swap for your own.
Our assumptions: a 4kW system in the Midlands costing £7,000, generating 3,400 kWh a year. Electricity bought from the grid at 26.32p per kWh (Ofgem’s cap rate for the final quarter of 2026). Export paid at 12p per kWh, which is a realistic mainstream rate rather than a headline one.
The critical number is self-consumption — the share of what your panels generate that you actually use yourself, rather than exporting. Every kWh you use yourself is worth 26.32p to you. Every kWh you export is worth 12p. The gap is more than double.
| Solar only | Solar + 5kWh battery | |
|---|---|---|
| Installed cost | £7,000 | £11,000 |
| Annual generation | 3,400 kWh | 3,400 kWh |
| Self-consumption rate | 35% | 70% |
| Electricity you avoid buying | 1,190 kWh = £313 | 2,380 kWh = £626 |
| Electricity exported | 2,210 kWh = £265 | 1,020 kWh = £122 |
| Total annual benefit | £578 | £748 |
| Simple payback | ~12 years | ~15 years |
Look carefully at that last row, because it is the opposite of what most solar advertising implies.
The battery increases your annual saving but lengthens your payback. It adds £170 a year in this example, and costs £4,000. That is a 23-year return on the battery alone, against a typical 10-year manufacturer warranty.
This is not an argument against batteries. It is an argument against buying one without doing this specific calculation for your own household. A battery earns its keep when it is doing more than storing surplus solar — for instance charging overnight on a cheap off-peak tariff and discharging during the expensive evening peak, or exporting into a high time-of-use rate. On a standard flat tariff, storing solar alone, the numbers are much harder to justify.
How your roof changes everything
Orientation and shading affect output more than panel brand does. As a rough guide, relative to a perfect south-facing pitched roof:
| Orientation | Approx. output | Verdict |
|---|---|---|
| Due south | 100% | Ideal |
| South-east / south-west | ~95% | Barely any loss |
| East / west | ~80% | Still viable, and spreads generation across morning and evening |
| North-east / north-west | ~65% | Marginal |
| Due north | ~60% | Rarely worth it |
An east-west split is not the disaster it sounds. It produces less in total, but it produces earlier and later in the day, which can push your self-consumption rate higher than a south-facing array that peaks at noon when nobody is home.
Shading is the bigger threat. A single chimney, aerial or neighbouring tree shading part of one panel can drag down a whole string of panels on a basic string inverter. If you have any shading, ask specifically about power optimisers or micro-inverters.
Seasonality is worth bracing for too: roughly 70% of a UK system’s annual generation arrives between April and September. December output can be under a tenth of June’s. That is normal, not a fault.
The Smart Export Guarantee: the part most people get wrong
The Smart Export Guarantee (SEG) replaced the old Feed-in Tariff in January 2020. Under it, every licensed electricity supplier with 150,000 or more customers must offer at least one tariff paying you for electricity you export to the grid. Smaller suppliers can opt in voluntarily.
The crucial difference from the old Feed-in Tariff: there is no government-set rate. Suppliers decide their own, and the only rule is that it must be above zero. Which is why the spread is enormous.
What the rates look like
Rates as reported through mid-2026 fell into three broad bands:
| Band | Typical rate | The catch |
|---|---|---|
| Top tier | 17.5p–25p per kWh | Usually requires that the supplier installed your system, and that you buy your electricity from them. Often fixed for 12 months. |
| Bundled mainstream | 12p–16.5p per kWh | Requires you to take your import supply from the same company. |
| Standalone | 3p–6p per kWh | No switching required — and it shows in the rate. |
| Time-of-use | Up to 30p+ at peak | Needs a battery and a smart meter. You are paid the high rate only for exports during the evening peak window, typically 4–7pm. |
Reporting through 2026 pointed to Good Energy at the top of the fixed-rate market at around 25p for its own installations, with So Energy and OVO around 20p, EDF around 18p and E.ON Next around 16.5–17.5p. British Gas sat near 15p. Octopus cut its Outgoing tariff from 15p to 12p on 1 March 2026, which removed what had been many people’s default choice.
Do the arithmetic on that spread. Exporting 2,200 kWh a year at 15p earns £330. The same electricity at 4p earns £88. Same panels, same roof, same sunshine — a £242 annual difference from a form you fill in once.
1. Your export supplier does not have to be your electricity supplier. You can buy power from one company and be paid for exports by another — though, as the table shows, most of the better rates are conditional on bundling.
2. SEG payments are not automatic. Installing panels does not enrol you. You have to apply directly to a supplier. Electricity you export before you sign up earns you nothing.
What you need to qualify
- An eligible low-carbon system — solar PV, wind, hydro, anaerobic digestion or micro-CHP — within the capacity limits.
- MCS certification (or an accepted equivalent) for both the installation and the installer. Suppliers routinely ask to see the certificate.
- A meter capable of half-hourly export readings — in practice, a smart meter — plus an export MPAN. That is a different number from the import MPAN on your bill; your export supplier normally arranges it.
- The property must be in Great Britain. SEG is not available in Northern Ireland.
This is the practical reason MCS certification matters so much. It is not a badge. Without it, most suppliers will not put you on a SEG tariff at all, which quietly removes a chunk of your return for the next 25 years.
The scheme is not a niche curiosity, either. Ofgem reported 270,395 registered installations by the end of SEG Year 5, with around £57 million paid out for 443 GWh of exported electricity across that year.
Grants in 2026: what is real and what is not
“Free solar panels” advertising is relentless, and mostly misleading. Here is the honest position as of September 2026.
0% VAT — open to everyone
Solar panels, batteries and their installation are zero-rated for VAT on residential properties. This is the one incentive that applies regardless of income, benefits or EPC rating. It is worth roughly £1,000–£2,000 on a typical installation, and the current zero rating runs until 31 March 2027.
ECO4 — closing 31 December 2026
The Energy Company Obligation is the scheme that can genuinely fund solar in full, but it is not a cash grant. It is an obligation on large energy suppliers to fund efficiency upgrades for eligible households, delivered through approved installers.
Broad eligibility: your property has an EPC rating of D, E, F or G, and someone in the household receives a means-tested benefit such as Universal Credit, Pension Credit, Housing Benefit, income-based JSA or ESA, or Income Support. Some councils also refer households through “LA Flex”, which uses local fuel-poverty criteria rather than benefits — worth asking your council about if you are on a low income but not on benefits.
The important caveat: ECO4 is a whole-home retrofit scheme, not a solar scheme. It leads with insulation and heating, because in a cold, inefficient home those do more good. Solar can be included where the property assessment supports it, but standalone solar is rarely funded.
The government confirmed a nine-month extension in January 2026, moving the close from 31 March to 31 December 2026. There will be no ECO5. Applications take time to process and installer capacity tightens as any scheme approaches its deadline, so if you think you qualify, this is genuinely a case for acting rather than waiting.
The Great British Insulation Scheme — closed
GBIS ended on 31 March 2026 and has not been directly replaced.
The Warm Homes Plan — from January 2027
This is the successor, and it is a structural change rather than a rebrand. Instead of obliging energy suppliers to fund upgrades (a cost that ultimately sits on everyone’s bills), the Warm Homes Plan is funded by direct government spending, with a headline commitment in the £13–15 billion range across this parliament and a target of upgrading five million homes by 2030. Rooftop solar is explicitly in scope.
Two elements are relevant to solar buyers: fully funded packages for low-income households through the Warm Homes: Local Grant, delivered by local councils; and a low-interest or interest-free loan scheme intended to be open to all households. Detailed eligibility and loan terms were still being finalised through 2026.
How to read a solar quote properly
Get three quotes. Not one. The spread on identical specifications is routinely large enough to fund a battery.
When comparing them, the headline price tells you almost nothing on its own. These are the line items that matter:
1. Exact equipment, named
A quote that says “solar system” or “10 panels” is not a quote. You want the panel manufacturer and model, the wattage per panel, the inverter make and model, and if a battery is included, its brand and usable capacity in kWh. Usable capacity, not nominal — they are not always the same number.
2. Predicted annual generation in kWh
Not the number of panels. Ask for the estimated annual output in kilowatt-hours, and ask whether the figure accounts for your roof’s actual orientation and any shading. An MCS-certified installer produces this as standard.
3. What is included in the price
Scaffolding, electrical work, DNO notification, bird protection mesh, DC isolators, monitoring hardware, MCS certificate, and making good afterwards. Ask directly whether anything is excluded.
4. Two separate warranties
There is the product warranty from the manufacturer, and the workmanship warranty from the installer. The second is the one people forget. If a roof penetration leaks in year four, the panel manufacturer is not the one fixing your ceiling. Ask how long the workmanship cover runs and whether it is insurance-backed, meaning it survives the installer going out of business.
5. Grid connection paperwork
Systems with an inverter rated at 3.68kW or below fall under G98 and can be connected with notification to your Distribution Network Operator afterwards. Larger systems need G99 approval before installation, which takes time. Confirm which applies and who is handling it.
6. Certification you can verify
MCS certification is the one that determines your SEG eligibility. RECC and TrustMark provide consumer protection and dispute resolution. NAPIT or NICEIC covers electrical competence. Verify these on the certifying bodies’ own registers rather than trusting logos on a website. MCS, TrustMark and RECC all publish searchable databases.
7. Deposit protection
If you are asked for a deposit, ask how it is protected. Deposit and guarantee insurance exists precisely because installers occasionally fail between payment and installation.
Who solar genuinely suits — and who it does not
Strong case: you own your home and plan to stay 10+ years; you have an unshaded south, east or west-facing roof; someone is home during the day, or you can shift laundry, dishwashing and hot water to daylight hours; you have an EV or heat pump, or expect one; your electricity use is above average.
Weaker case: you may move within five years; your roof is heavily shaded or predominantly north-facing; your household is out all day and on a flat tariff with no battery; your roof covering needs replacing soon (do the roof first); you are in Northern Ireland, where SEG does not operate and the export picture is different.
None of these are absolute. A household that is out all day but adds a battery and a time-of-use tariff can do perfectly well. The point is that the answer is specific to your home and your habits, which is why a generic online calculator is a starting point rather than a conclusion.
Getting quotes
If you want a personalised assessment, Blue Ape Renewables is one MCS-certified installer offering free, no-obligation quotes for solar PV, battery storage, heat pumps and EV charging. They list MCS, NAPIT, RECC, TrustMark and Tesla Certified accreditations, and install Tesla Powerwall, GivEnergy and Fox ESS systems.
Get a free solar & battery quote →
This is an affiliate link — we may earn a commission if you buy. We would give you the same advice either way: get at least three quotes and compare them line by line using the checklist above. One quote is not a comparison, whoever it comes from.
Frequently asked questions
How long do solar panels last?
Panels typically carry 25-year performance warranties, with output degrading gradually — usually guaranteed to remain above roughly 80–85% of original capacity at year 25. They generally keep working beyond that, just less efficiently. Inverters are the shorter-lived component, often needing replacement at 10–15 years. Budget £800–£1,500 for that when assessing lifetime returns.
Do solar panels work on cloudy days?
Yes, but at reduced output. Panels respond to daylight rather than direct sunshine, so they generate on overcast days at a fraction of peak capacity. This is why UK annual output figures already account for the weather — 3,400 kWh from a 4kW system is a real-world British number, not a Mediterranean one.
Do I need planning permission?
For most homes, no. Roof-mounted solar on a domestic property usually falls under permitted development in England, Scotland and Wales. The main exceptions are listed buildings, homes in conservation areas or National Parks, and flat-roof or ground-mounted installations. Check with your local planning authority if any of those apply.
Will solar panels increase my home’s value?
Evidence points to a modest positive effect, mainly through the improved EPC rating and the appeal of lower running costs. But treat it as a secondary benefit rather than a reason to install. Buyers value an owned system considerably more than one under a lease or rent-a-roof arrangement, which can complicate a sale.
Should I get a battery at the same time or add one later?
Retrofitting is possible but usually costs more than doing it together, because you may need to replace or supplement the inverter. If a battery is a realistic possibility within a few years, ask for a hybrid (battery-ready) inverter at the outset. It costs a little more now and avoids a much larger bill later.
What happens to my panels during a power cut?
By default, nothing — the system shuts down for safety, so grid engineers are not working on live wires. Your panels will not power your home during an outage unless you have a battery with a dedicated backup function and the correct gateway hardware. If blackout resilience matters to you, say so explicitly at quotation stage, because it is not standard.
Do I pay tax on SEG income?
HMRC provides a £1,000 annual trading allowance, and typical household export earnings fall comfortably below it. If your circumstances are unusual, check with HMRC or an accountant — we are not tax advisers.
Can I get SEG payments if I already have Feed-in Tariff?
The Feed-in Tariff closed to new applicants in 2019, but existing participants continue under their original agreements, which are generally more generous than SEG. Switching schemes is rarely worthwhile. If you are on FiT, check your export terms before changing anything.
Are solar panels worth it in Scotland?
Yes, though payback is longer. Scottish output typically runs 10–15% below southern England, pushing typical payback towards 11–14 years rather than 7–9. Scotland also has its own support schemes separate from ECO4 and the Warm Homes Local Grant, so check devolved options.
The verdict
Solar panels are worth it for a large number of UK households in 2026 — but for reasons more specific than the advertising suggests.
The economics work best when three things line up: a decent roof, a household that can use a good share of what it generates during daylight hours, and a competitive export tariff. Get those right and a 4kW system returning £500–£600 a year against a £7,000 outlay is a solid, low-risk return on capital, especially with electricity at 26p a unit and the price cap forecast to rise again in early 2027.
Where people lose money is in the details: overpaying by £2,000 because they took the first quote; adding a £4,000 battery that saves £170 a year on the wrong tariff; or never signing up to SEG at all and giving away 2,000 kWh a year for free.
So the practical sequence is: work out your annual electricity consumption from your bills, get three itemised quotes from MCS-certified installers, compare them on predicted kWh and total specification rather than headline price, and choose your export tariff deliberately rather than accepting whatever your installer suggests.
Do that, and you will know whether solar is worth it for your house — which is the only version of the question that has a real answer.
Sources and dates
Installation costs: MCS installation data and market surveys, 2026. Electricity unit rate and price cap: Ofgem, price cap for 1 October to 31 December 2026 (announced 26 August 2026). SEG rules and eligibility: Ofgem and Energy Saving Trust. SEG rate bands: supplier tariff comparisons published between May and August 2026. ECO4 extension: government consultation response, 23 January 2026. Warm Homes Plan: GOV.UK, January 2026. VAT: zero rating on residential energy-saving materials to 31 March 2027.
This article is general information, not financial advice. Energy tariffs, grant schemes and prices change frequently — verify current figures with the relevant supplier or scheme before making a decision.
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