Official figures · every line of the quote · VAT, grants and loans
Solar Panel Installation Cost in 2026: the real figures, line by line
The Energy Saving Trust’s £7,600, DESNZ’s cost-per-kW medians with the multiplication shown, PVGIS yields for Guildford and Woking, the 0% VAT position, the income-linked grant routes and what each line of a quote pays for. We do not publish a price list: the number for your roof comes from a survey.
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Solar panel installation cost is the question every page on the subject answers with a range and no source. This page does it the other way round. The figures below are the Energy Saving Trust’s and DESNZ’s, dated, with the multiplication shown, so you can see how a national average is built and why your house will land somewhere else. Energy Saving Trust puts a typical system at around 4.5 kWp, around 12 panels, costing around £7,600 installed. DESNZ’s May 2026 cost data, drawn from 264,742 installations, gives medians of £1,595 and £1,546 per kW. Neither is our price, and that is the point.
We do not print an HCE figure anywhere on this site. A real number depends on your roof, your usage and your electricity supply, and the only honest way to produce it is a survey. What we can do is show where the official answer to what solar panels cost comes from, what every line of a quote pays for, which seven things move the price, and how VAT, grants and loans work in 2026 — so that when two quotes arrive for a home in and around Guildford, or anywhere across Surrey, you can read them properly.
Quick answer
Solar panel installation cost, in short:
- Energy Saving Trust (27 August 2026): a typical 4.5 kWp system, around 12 panels, costs around £7,600 installed
- DESNZ Solar PV cost data (May 2026): median £1,595 per kW for 0 to 4 kW systems and £1,546 per kW for 4 to 10 kW, batteries excluded — so 4 kWp × £1,546 = £6,184 and 4.5 kWp × £1,546 = £6,957
- A 4 kWp south-facing roof in Guildford generates about 3,974 kWh a year (PVGIS 5.3), against Ofgem’s typical household use of 2,500 kWh
- VAT is 0% on residential solar panels and batteries until 31 March 2027, then 5% (HMRC VAT Notice 708/6)
- There is no general solar grant in England; ECO4 (to 31 December 2026) and the Warm Homes: Local Grant are income-linked, and the Warm Homes Loan Scheme caps at £15,000 for solar PV
- Export rates under the Smart Export Guarantee are set by each supplier and must be above zero — they change on short notice, so we never print one
- We do not publish an HCE price: the number for your roof comes from a free survey
Sources: Energy Saving Trust (updated 27 August 2026), DESNZ Solar PV cost data (May 2026), PVGIS 5.3, HMRC VAT Notice 708/6 and Ofgem — read 12 October 2026.
What the official figures say
Energy Saving Trust’s page Solar panels: costs, savings and benefits explained, updated 27 August 2026, describes the typical domestic system as around 4.5 kWp — around 12 panels over 20 to 30m² of roof — costing around £7,600 installed. It is the number most other results on this subject are quoting, with or without saying so.
The more useful figure is DESNZ’s Solar PV cost data, published May 2026, which analysed 264,742 installations from the 2025/26 financial year (batteries excluded, Northern Ireland excluded). The median cost per kW installed was £1,595 for systems of 0 to 4 kW, £1,546 for 4 to 10 kW and £1,204 for 10 to 50 kW. For domestic retrofits — nearly 90% of domestic installs — the mean was £2,109 per kW at 0 to 4 kW and £1,651 per kW at 4 to 10 kW; new-build installs came in at £1,518 and £1,440.
Multiplied out for the two sizes people actually ask about:
- 4 kWp at the 4 to 10 kW median: 4 × £1,546 = £6,184
- 4 kWp at the 0 to 4 kW median: 4 × £1,595 = £6,380 — a 4 kW system sits on the boundary of the two bands, so both apply
- 4 kWp at the domestic retrofit mean: 4 × £1,651 = £6,604
- 4.5 kWp at the 4 to 10 kW median: 4.5 × £1,546 = £6,957
- 4.5 kWp at the domestic retrofit mean: 4.5 × £1,651 = £7,429.50, call it £7,430 — within sight of the Energy Saving Trust’s around £7,600
Read those as the cost of an average job, not as a package price. A median is the middle of a quarter of a million very different roofs, and a mean runs higher because a minority of awkward jobs pull it up — which is why the retrofit mean for small systems reaches £2,109 per kW: a small array carries the same scaffold and the same commissioning as a larger one, spread over fewer kilowatts. None of this is an HCE quote. It is the backdrop you hold a quote against.
What you are actually paying for
A quote that arrives as a single number is hiding ten lines. Here is what they are and why each one exists.
- Panels. Make, model, rated output and count. Panels are designed to last 25 to 30 years, which is why the panel line is not the place to economise.
- Inverter. Converts the DC from the roof into AC for the house. Inverters typically carry shorter warranties than panels, and it is the inverter’s rated output, not the array size, that decides the grid paperwork below.
- Mounting system. Rails, hooks and flashings for an on-roof array, or the tray system for in-roof.
- DC and AC protection. Isolators, over-current and surge protection, and the cabling between the roof and the consumer unit.
- Scaffolding. Depends on how many elevations need access and for how long — the line that varies most between two houses of the same size.
- MCS-certified labour. The installation itself, by a certified installer. HCE holds MCS certification for solar PV through NAPIT (member 73495) and is a HIES Consumer Code member (HCE/A/1392).
- DNO notification or application. Under G98, type-tested generation up to and including 16 A per phase (3.68 kW) is notified to the network operator before commissioning or no later than 28 days after it. Anything above 16 A per phase needs a G99 application approved before the work starts.
- Commissioning. Testing, inspection and switch-on.
- Handover documents. The MCS certificate and the electrical certification, which arrive after the installation is registered, plus manuals and warranty registrations.
- Workmanship warranty. The installer’s own guarantee on the work, separate from the manufacturers’ product warranties.
If a quote does not show those lines, ask for them. The exercise is the same one we walk through in what is in a solar quote, line by line, and it does the same job: it makes two quotes comparable, and it shows which installer has actually looked at your roof.
The seven things that move the price
Two houses on the same road can be quoted hundreds of pounds apart for the same number of panels. These are the seven reasons, in roughly the order they matter.
- 1. System size in kWp. The biggest single driver, but not a proportional one: DESNZ’s median falls from £1,595 per kW at 0 to 4 kW to £1,546 per kW at 4 to 10 kW because the fixed costs — scaffold, commissioning, paperwork — are spread over more panels.
- 2. Roof type, pitch and access. A straightforward scaffold on one elevation of a semi-detached house costs less than wrapping a detached house with a conservatory in the way. The roof covering matters too, because different tiles need different fixings and different care.
- 3. In-roof or on-roof. In-roof trays replace the tiles beneath the array and sit flush; on-roof rails sit above the existing covering. In-roof usually makes sense on a new roof or a re-roof, on-roof on an existing one. Under permitted development a pitched-roof array must not protrude more than 0.2 m from the roof slope and must not sit higher than the highest part of the roof (chimneys excluded), so ask the surveyor to confirm the array height against that.
- 4. Inverter choice, and the G99 line. A 4 kW inverter draws 17.39 A per phase, just over the 16 A (3.68 kW) G98 limit, so it needs a G99 application approved before the work starts rather than a notification afterwards. Network operators aim to answer small fast-track applications within about 10 working days. The choice between a 3.68 kW inverter and a larger one is a design decision your surveyor should explain, not a surprise on the day.
- 5. Whether a battery is added. The Energy Saving Trust puts a home battery at £1,500 to £10,000, with a 5 kWh system at around £4,600. Fitted on the same visit, it shares the scaffold, the electrician and the paperwork. More on this below.
- 6. Roof repairs first. Panels are designed to last 25 to 30 years; if the roof underneath will not, the sensible order is repair, then panels, and a good survey says so even though it delays the job.
- 7. Flat roofs and designated land. A flat roof means a tilted frame, which under permitted development may rise no more than 0.6 m above the highest part of the roof. On article 2(3) land — conservation areas, the Surrey Hills National Landscape, National Parks — a flat-roof array needs an application to the council for a determination on prior approval before work starts, and a listed building needs listed building consent for any array. Conservation-area roof slopes, front ones included, are not restricted: the exclusion applies only to equipment on a wall, balcony or roof enclosure fronting a highway.
Where you are matters less than the roof does — PVGIS puts Guildford and Woking within 10 kWh a year of each other for the same 4 kWp array (3,984 − 3,974) — but the planning map does vary by borough, which is why our solar panels Surrey and solar panels Guildford pages go into the local detail.
Adding a battery
Energy Saving Trust’s Battery storage advice, updated 19 August 2026, gives the range: a home battery can cost £1,500 to £10,000, a 5 kWh system costs around £4,600, and a typical home system might be 10 kWh. Typical lifespan is about 10 to 12 years, which means a battery will usually be replaced once within the 25 to 30 years the panels are designed to last. Budget for that in the payback sum rather than discovering it later.
Two practical points from the same source. First, there is no exact formula — sizing comes from your own consumption, so a quote that sizes the battery before asking about your evening usage has guessed. Second, fitting storage at the same time as panels costs less than a separate visit later: one visit, one set of paperwork. If you are weighing it, our solar battery storage cost page takes the Energy Saving Trust’s figures line by line, and battery storage explains what the systems do and who they suit. For the two halves added up — panels and battery as one job, with DESNZ's battery statistics alongside the solar ones — see solar panels and battery cost.
Want a priced, itemised quote for your roof rather than a national average?
A free survey gives you the array size, the inverter, the scaffold, the DNO route and the VAT line for your house, itemised so you can hold it against anyone else’s.
VAT, grants and loans — what is real
HMRC’s VAT on energy-saving materials and heating equipment (VAT Notice 708/6) is clear: residential installations of solar panels and batteries in Great Britain are zero-rated — 0% — until 31 March 2027, then 5% from 1 April 2027. The reduced rate, not 20%. A home EV chargepoint is not on the energy-saving-materials list, so a charger added to the same job is standard-rated at 20% and should sit on its own line. Our guide to VAT on solar panels and batteries covers the edge cases.
There is no general government grant for household solar in England. What exists is income-linked. ECO4 runs to 31 December 2026 after a nine-month extension (the Great British Insulation Scheme closed on 31 March 2026). The Warm Homes: Local Grant covers privately owned homes in England — owner-occupied or privately rented — at EPC D to G, where the household is in a low-income postcode (IMD deciles 1 to 2), receives a means-tested benefit, or has a gross household income of £36,000 or less. Councils usually make contact within 10 working days of an application, and batteries are funded only alongside solar PV (DESNZ guidance updated 2 July 2026).
The Warm Homes Loan Scheme (scheme rules September 2026) is a lender loan, not a grant: capped at £15,000 for solar PV and £15,000 for a battery, with the government paying lenders up to 20% of the loan to bring the interest rate down. It is lower-interest, not zero-interest, and the repayments belong in your payback sum.
Surrey also has Solar Together Surrey, the county group-buying scheme for solar PV and battery storage run with Surrey County Council since 2021 — around 1,400 installations in its first phase — with free registration at solartogether.co.uk/surrey, run in rounds. Registering and getting an independent quote are not mutually exclusive, and having both in front of you is the whole point of this page. The same line-by-line approach runs through our air source heat pump cost and air conditioning installation cost pages, for households weighing more than one change at once.
What it earns back
The cost is half the sum. The other half is the yield, and for that we use PVGIS 5.3 (European Commission Joint Research Centre), database PVGIS-SARAH3, 2005–2023, with the parameters 4 kWp, 35° tilt, due south, 14% system losses, building-mounted. On those settings a 4 kWp array in Guildford generates about 3,974 kWh a year — about 993 kWh per kWp — with year-to-year variation of around ±144 kWh (run 12 October 2026). Woking comes out at about 3,984 kWh, or 996 kWh per kWp (run 10 September 2026). East- or west-facing roofs generate less, and shading changes the answer more than the town does.
For scale, Ofgem’s Typical Domestic Consumption Value from 1 July 2026 is 2,500 kWh a year for a medium, single-rate household, so a 4 kWp roof in Guildford generates about 1.6 times what a typical home uses (3,974 ÷ 2,500 = 1.59). The catch is timing: the roof generates in daylight and most homes use most of their electricity outside it, so what you earn depends on the share you use yourself.
The unit rate to set against self-used generation is around 26p per kWh — the 26.32p per kWh Ofgem price-cap unit rate for October to December 2026 (Direct Debit). As an illustration only, not a forecast: if a household used 40% of that Guildford yield itself, that is 3,974 × 0.4 = 1,589.6 kWh, and 1,589.6 × 26.32p = £418.38 a year of electricity not bought, call it £418. Each further 10 percentage points of self-use is 3,974 × 0.1 = 397.4 kWh, and 397.4 × 26.32p = £104.60. The remainder is exported under the Smart Export Guarantee at a rate that is set by each supplier and must be above zero — they change on short notice, which is why we never print one. To be paid for export at all you need an MCS certificate for the installation and a meter capable of half-hourly export readings; suppliers with 150,000 or more domestic customers must offer a tariff. Solar does not touch the 54.83p a day standing charge.
Put the two halves together and you have a payback period. Energy Saving Trust’s own payback table, with export payments included and fuel prices as of July 2026, has a London home reaching break-even in about 9 years. We go through the method, and what shifts it, in solar panel payback time in the UK and how much can solar panels save, and our savings calculator lets you try your own numbers.
How to compare two quotes
Two quotes are only comparable once they are itemised the same way. Before you look at the totals, line them up on these.
- Itemised lines. Panels (make, model, count, rated output), inverter (make and rated output), mounting, protection, scaffold, labour, commissioning, handover. A missing line is either included silently or excluded silently; ask which.
- Before and after VAT. Both totals, with the treatment stated: 0% until 31 March 2027 for the residential solar and battery work, 20% for a chargepoint on the same job.
- Warranties, separately. Panel product and performance warranties, the inverter warranty (typically shorter), the battery warranty if there is one, and the installer’s own workmanship guarantee, each with its length written down.
- MCS and the certificate. That the installer is MCS-certified for solar PV specifically — certification is granted per technology — and that the quote includes registering the installation, because the MCS certificate is what a Smart Export Guarantee application needs.
- The DNO route. Whether the inverter sits within the 16 A G98 limit and is notified after commissioning, or above it and needs G99 approval before the work starts, and who is submitting it.
- What is excluded. Roof repairs, a consumer-unit upgrade, bird-proofing, monitoring, a battery, an EV charger: a cheaper total is often a shorter list.
Our solar panel installation page explains how a survey with us runs for homes in and around Guildford and across Surrey. If you would rather talk it through first, get in touch or call 0204 547 1892.
Sources: Energy Saving Trust — Solar panels: costs, savings and benefits explained (updated 27 August 2026) · Energy Saving Trust — Battery storage (updated 19 August 2026) · DESNZ — Solar PV cost data, May 2026 (2025/26 financial year, 264,742 installations) · PVGIS 5.3 (European Commission Joint Research Centre), PVGIS-SARAH3, 2005–2023, 4 kWp, 35° tilt, due south, 14% system losses, building-mounted (Guildford run 12 October 2026, Woking run 10 September 2026) · HMRC — VAT on energy-saving materials and heating equipment (VAT Notice 708/6) · Ofgem — Smart Export Guarantee and the October to December 2026 price cap · GOV.UK — Warm Homes: Local Grant guidance (DESNZ, updated 2 July 2026) and Warm Homes Loan Scheme rules (September 2026) · ENA EREC G98 Issue 2 (10 March 2025). All read 12 October 2026.
Solar panel installation cost: your questions
How much do solar panels cost in the UK in 2026?
Two official figures frame it. The Energy Saving Trust (updated 27 August 2026) puts a typical domestic system at around 4.5 kWp, around 12 panels, costing around £7,600 installed. DESNZ’s Solar PV cost data (May 2026, 264,742 installations in 2025/26, batteries excluded) gives a median of £1,595 per kW for systems up to 4 kW and £1,546 per kW for 4 to 10 kW. Multiply out and a 4 kWp job sits at £6,184 to £6,380 on the medians; the domestic retrofit mean of £1,651 per kW gives £6,604. Those describe the average job, not a package price; your figure comes from a survey of your roof and usage.
Is there a grant for solar panels?
Not a general one. There is no government grant for household solar in England that anyone can claim. The routes that exist are income-linked: ECO4, which runs to 31 December 2026, and the Warm Homes: Local Grant for privately owned homes in England at EPC D to G, where the household is in a low-income postcode (IMD deciles 1 to 2), receives a means-tested benefit, or has a gross household income of £36,000 or less. Batteries are funded only alongside solar PV. Separately, the Warm Homes Loan Scheme offers lower-interest lender loans capped at £15,000 for solar PV and £15,000 for a battery.
Is VAT charged on solar panels?
Not at the moment, on a residential installation. Under HMRC VAT Notice 708/6, solar panels and batteries installed in residential accommodation in Great Britain are zero-rated until 31 March 2027. From 1 April 2027 the rate reverts to the reduced 5%, not the standard 20%. Two things to check on a quote: that it states the VAT treatment it has applied, and that it covers supply and installation together, because the relief attaches to the installed work. A home EV chargepoint is not on the energy-saving-materials list, so a charger added to the same job is standard-rated at 20% and should appear as its own line.
How much does a 4 kW solar system cost?
Take DESNZ’s published figures and multiply. A 4 kW system sits on the boundary of its two domestic bands: at the 0 to 4 kW median of £1,595 per kW it is £6,380; at the 4 to 10 kW median of £1,546 per kW it is £6,184; at the domestic retrofit mean of £1,651 per kW it is £6,604. Those are the cost of an average job in 2025/26, batteries excluded. What moves a specific house away from them is scaffolding, roof access, inverter choice and whether a G99 application is needed, because a 4 kW inverter draws 17.39 A, just over the 16 A G98 line. A survey settles it.
What does a solar panel installation quote include?
A proper quote is itemised. Expect the panels with make, model and count; the inverter with its rated output; the mounting system and whether it is on-roof or in-roof; DC and AC isolation and protection; scaffolding; MCS-certified labour; the DNO notification under G98, or the G99 application for larger inverters; commissioning; and the handover pack with the MCS certificate, electrical certification and warranties. The MCS certificate and electrical certification arrive after the installation is registered, and you need them to apply for a Smart Export Guarantee tariff. If any of those lines is missing, ask whether it is included or excluded before you compare totals.
How long until solar panels pay for themselves?
The Energy Saving Trust’s payback table, with export payments included and fuel prices as of July 2026, shows a London home reaching break-even in about 9 years. What moves that for a Surrey home is how much of the generation you use yourself rather than export. PVGIS puts a 4 kWp south-facing roof in Guildford at about 3,974 kWh a year, and every unit used in the house displaces electricity priced at around 26p, the 26.32p per kWh October to December 2026 cap rate. Export earns a supplier-set rate that must be above zero but changes on short notice, so we do not print one. A battery shifts the balance towards self-use.
Want the real number for your roof?
Request a free, no-obligation survey and you will get the array size, the inverter and its DNO route, the scaffold, the handover documents and the VAT line, itemised so it is comparable with anyone else’s. See also residential solar panel installation and what is in a solar quote, line by line.
Get a free quote · Call 0204 547 1892 · Read the solar panels Surrey guide