Solar Panel System Cost by Size: 3kW to 12kW (2026 UK)
A typical 4kWp solar panel system costs £4,275-£5,175 installed in 2026. Prices scale with size: around £3,450-£4,250 for 3kW, £5,700-£7,000 for 6kW, £8,300-£10,500 for 10kW and up to £12,200 for a large 12kW array. Battery storage adds £2,500-£7,000 depending on capacity. This guide breaks down installed costs by system size (kWp), panel count and battery size, with realistic generation, savings and payback figures, using installer pricing across 519 UK towns.
- ✓ Real installed prices, not bare hardware costs
- ✓ 3kW to 12kW systems compared panel by panel
- ✓ Battery storage and export earnings covered
- ✓ MCS-certified installers, free no-obligation quotes
Solar System Cost by Size: Quick Answer
In 2026, a typical 4kWp solar system costs £4,275-£5,175 installed, and prices scale from about £3,450 for a 3kW system up to £9,600-£12,200 for 12kW, with bigger systems costing noticeably less per kWp. A 10kW solar system costs £8,300-£10,500 installed, the most-searched size in the UK right now. Add £2,500-£7,000 for battery storage depending on usable capacity, and expect roughly 850-950 kWh of generation per kWp per year from a south-facing roof.
Jump to: Cost by system size · Cost by panel count · Cost chart · Battery prices · What's included · 50kW & 100kW commercial · How to save · FAQs
Solar Panel System Cost by Size (kWp): 2026 Installed Prices
System size is measured in kilowatts-peak (kWp), the maximum output of the panels in ideal conditions. Modern residential panels are typically 430-470W each, so a 4kWp system is now only 9-10 panels where it needed 16 a decade ago. The prices below are full installed costs: panels, inverter, mounting, scaffolding, labour, electrical work and MCS certification, benchmarked against our live pricing dataset covering 519 UK towns. Solar installations are zero-rated for VAT until 31 March 2027, and that is already reflected in these figures.
| System size | Panels needed (430W) | Roof area | Installed cost (2026) | Est. annual generation | Typical annual saving | Rough payback |
|---|---|---|---|---|---|---|
| 3 kWp | 7 | ~14 m² | £3,450-£4,250 | 2,550-2,850 kWh | £360-£630 | 7-11 years |
| 4 kWp | 9-10 | ~20 m² | £4,275-£5,175 | 3,400-3,800 kWh | £480-£840 | 6-10 years |
| 5 kWp | 12 | ~24 m² | £5,000-£6,100 | 4,250-4,750 kWh | £600-£1,050 | 6-10 years |
| 6 kWp | 14 | ~28 m² | £5,700-£7,000 | 5,100-5,700 kWh | £710-£1,250 | 6-9 years |
| 8 kWp | 19 | ~38 m² | £7,000-£8,800 | 6,800-7,600 kWh | £950-£1,670 | 5-9 years |
| 10 kWp | 23-24 | ~47 m² | £8,300-£10,500 | 8,500-9,500 kWh | £1,190-£2,090 | 5-8 years |
| 12 kWp | 28 | ~56 m² | £9,600-£12,200 | 10,200-11,400 kWh | £1,430-£2,500 | 5-8 years |
Generation assumes a south-facing, largely unshaded roof at 850-950 kWh per kWp per year (the UK average band). East-west roofs generate roughly 10-15% less; the far north of Scotland around 5-10% less. Savings assume you use 40-70% of the power at home and export the rest, so treat them as a range, not a promise.
Two things stand out. First, the price per kWp falls as systems get bigger: from roughly £1,150-£1,400 per kWp at 3kW down to £800-£1,015 per kWp at 12kW, because scaffolding, labour call-out, the inverter and paperwork are largely fixed costs spread over more panels. Second, payback improves with size for the same reason, provided you can actually use or export the extra power.
One practical wrinkle for larger systems: your installer must notify the District Network Operator. Systems up to 3.68kW of inverter output per phase only need a G98 notification after installation, but anything above that needs G99 approval before switch-on. On a standard single-phase supply, 10kW and 12kW arrays are usually fitted with export limitation, or you can pay your DNO for a three-phase upgrade. A good installer handles all of this for you, but it can add a few weeks to the timeline.
If you want the deep-dive on the standard domestic install, including panel brands, inverter types and region-by-region pricing, see our full solar panels cost guide.
Solar Panel Cost by Number of Panels: 8 to 24 Panels
Plenty of people think in panels rather than kilowatts, so here is the same 2026 pricing expressed by panel count. These figures assume today's standard 430W residential panels; if your installer quotes 450W or 470W panels you will need slightly fewer for the same output.
| Number of panels | System size (430W panels) | Roof area | Installed cost (2026) | Est. annual generation |
|---|---|---|---|---|
| 8 panels | ~3.4 kWp | ~16 m² | £3,900-£4,700 | 2,900-3,250 kWh |
| 10 panels | ~4.3 kWp | ~20 m² | £4,400-£5,400 | 3,650-4,100 kWh |
| 12 panels | ~5.2 kWp | ~24 m² | £5,100-£6,300 | 4,400-4,950 kWh |
| 16 panels | ~6.9 kWp | ~31 m² | £6,300-£7,900 | 5,850-6,550 kWh |
| 20 panels | ~8.6 kWp | ~39 m² | £7,400-£9,300 | 7,300-8,150 kWh |
| 24 panels | ~10.3 kWp | ~47 m² | £8,500-£10,800 | 8,750-9,800 kWh |
A quick sense-check against the size table above: 10 solar panels cost £4,400-£5,400 installed and land just above the classic 4kWp system, 16 panels cost £6,300-£7,900 for a substantial 6.9kWp array, and 24 panels cost £8,500-£10,800, taking you into 10kW territory with the same DNO considerations described above.
How much does one solar panel cost for a house?
A single 430-470W residential panel costs about £100-£220 as hardware, depending on brand tier and wattage. But a panel on its own does nothing: once you spread scaffolding, the inverter, labour and certification across a real installation, the effective installed cost works out at roughly £490-£610 per panel on a small 7-panel system, falling to about £340-£440 per panel on a 28-panel array. That is the clearest illustration of why bigger systems are better value.
Adding one extra panel to an existing array rarely stacks up either. Between scaffolding or access equipment and an electrician's time, a single-panel addition typically costs £300-£500 or more, and an older string inverter may not accept an extra panel without reconfiguration. If you are short on generation, it is usually better value to add a batch of panels or a battery in one visit.
Installed Solar Cost by System Size: 2026 Chart
The chart below plots the midpoint of each installed cost range. Note how the bars flatten as size increases: doubling a 5kW system to 10kW adds roughly 70% to the price, not 100%, because the fixed costs of the job stay the same. The 10kW bar is highlighted because it is currently the most-searched system size in the UK.
Want a figure tuned to your own roof, usage and region rather than a national band? Run your numbers through our free solar cost calculator, then compare it against real quotes.
Solar Battery Prices by Size: 5kWh, 10kWh and 13.5kWh
First, a naming point that trips a lot of people up: a "5kW solar battery" or "10kW solar battery" almost always means 5kWh or 10kWh of usable storage capacity. Kilowatts (kW) measure how fast a battery can charge or discharge; kilowatt-hours (kWh) measure how much energy it holds, and it is the kWh figure that drives the price.
| Usable battery capacity | Standalone retrofit cost | Cost when installed with new solar | Best suited to |
|---|---|---|---|
| 5 kWh | £2,500-£4,000 | £1,800-£3,000 | Smaller homes, 3-4kWp systems |
| 10 kWh | £4,000-£5,800 | £3,200-£4,800 | Typical 3-4 bed homes, 4-8kWp systems |
| 13.5 kWh | £5,000-£7,000 | £4,200-£6,000 | High usage, heat pumps and EVs, 8kWp+ systems |
Fitting a battery at the same time as the panels is consistently cheaper than retrofitting later, typically saving £700-£1,200, because the installer shares one hybrid inverter, one electrician visit and one set of paperwork across both jobs. A typical 4kWp solar-plus-battery bundle starts from around £8,075 installed in 2026. Standalone battery retrofits have also been zero-rated for VAT since February 2024, so there is no tax penalty either way until at least March 2027.
Whether a battery pays its way depends on the gap between your import unit rate and what you are paid to export. Export rates under the Smart Export Guarantee vary widely by supplier and change often; our sister site keeps a live table of the best UK solar export tariff rates this month. If you can secure a strong export rate, a smaller battery (or none at all) may serve you better than a large one. For chemistry, lifespan and brand-tier detail, see our dedicated solar battery cost guide.
What's Included in an Installed Solar Price?
Every price on this page is a full installed figure, and any quote you accept should be too. Watch out for headline prices that quietly exclude scaffolding or the DNO paperwork; this table is what a complete, MCS-compliant installed price covers.
| Item | Included in a proper installed price? | Notes |
|---|---|---|
| Scaffolding or access equipment | Yes | Worth £430-£650 on a typical semi; check it is itemised |
| Panels and mounting rails | Yes | 430-470W panels with 25-year performance warranties are now standard |
| Inverter (string or hybrid) | Yes | Expect one replacement at year 10-15, typically £500-£1,200, not covered |
| Labour: roofers plus electrician | Yes | Usually 1-2 days on site for domestic sizes |
| AC/DC wiring, isolators, generation meter | Yes | Connection into your consumer unit included |
| MCS certificate and handover pack | Yes | Essential: you cannot claim export payments without it |
| DNO notification (G98/G99) | Yes | Installer submits it; G99 approval needed above 3.68kW per phase |
| Bird/pigeon proofing mesh | Optional extra | Typically £400-£1,000; cheaper done at install than after |
| Battery storage | Optional extra | See battery table above |
| Roof repairs or structural strengthening | No | Priced separately if your survey flags them |
Also not included in standard quotes: a consumer unit upgrade if yours is dated (£300-£600) and a three-phase supply upgrade if you want a large system without export limitation, which is priced by your DNO.
50kW and 100kW Solar System Costs (Commercial)
Systems of 50kW and above are commercial installations for warehouses, farms, offices and factories, not homes, and they are priced differently: per kWp rates drop well below domestic levels, but every job is bespoke.
| System size | Typical rate per kWp | Indicative installed cost | Est. annual generation |
|---|---|---|---|
| 50 kW (commercial rooftop) | £700-£900 per kWp | £35,000-£45,000 | 42,500-47,500 kWh |
| 100 kW (commercial rooftop) | £650-£850 per kWp | £65,000-£85,000 | 85,000-95,000 kWh |
Treat these strictly as indicative bands. A real 50kW or 100kW project needs a structural survey of the roof, a shading and yield study, a G99 application to the DNO (and possibly network reinforcement costs), sometimes planning permission, and a commercial export or power purchase arrangement. Any installer quoting a firm price before doing that work is guessing. BestBuilders focuses on domestic projects; for commercial systems, go directly to MCS-certified commercial specialists and get at least three bespoke quotes.
What Affects the Price of a Solar System?
Scaffolding and access
A straightforward two-storey semi needs £430-£650 of scaffolding. Three-storey townhouses, steep pitches, conservatories below the work area or roofs over public footpaths all push access costs up, sometimes by several hundred pounds.
Roof type and pitch
Concrete tiles are the cheapest to work with. Slate is slower and more fragile, adding labour; flat roofs need ballasted or angled frames; and in-roof (integrated) panels look sleeker but cost roughly 10-20% more than standard on-roof mounting.
Inverter and electronics
A basic string inverter is included in the prices above. A hybrid inverter (battery-ready) adds a few hundred pounds, while per-panel optimisers or micro-inverters, worthwhile on shaded or multi-aspect roofs, typically add £800-£1,500 to a domestic system.
Single-phase vs three-phase supply
Most UK homes are single-phase, which comfortably suits systems up to about 8kW. Above that you are into G99 approval, export limitation or a paid three-phase upgrade, all of which add cost or paperwork time to 10-12kW installations.
Panel wattage and brand tier
Premium-tier panels carry longer product warranties and slightly better degradation figures, but cost more per watt. On an easy, unshaded roof, mid-tier 430-450W panels are usually the sweet spot; paying up for premium hardware rarely changes the payback maths in your favour.
Battery and optional extras
Storage is the single biggest optional cost (see the battery table above). Bird proofing at £400-£1,000 and emergency power supply (backup) functionality are the other common add-ons that move a quote.
Where you live
Labour rates vary sharply by region; see the regional note below.
How to Save Money on a Solar Installation
- Get at least three MCS-certified quotes. Installed prices for the identical system routinely vary by 20-30% between local installers. Request your free quotes here.
- Size the system to your usage, not your roof. The best payback comes from power you actually use. Divide your annual kWh usage by roughly 900 for a starting system size, then sanity-check it with our solar cost calculator.
- Add the battery at install time, not later. Doing both in one visit typically saves £700-£1,200 versus a retrofit.
- Check grant eligibility before paying full price. ECO4 and LA Flex can cover some or all of the cost for qualifying households; our guide to getting a solar panel grant in 2026 explains who qualifies and how to apply.
- Remember VAT is already 0%. Solar is zero-rated until 31 March 2027, so treat any sales pitch offering a special "government-backed VAT discount" as a red flag rather than a saving.
- Share scaffolding with other roof work. If you need roof repairs, fascias or gutters done, booking them alongside the solar install spreads £430-£650 of access costs across both jobs.
- Pick your export tariff deliberately. The spread between the best and worst export rates is wide enough to swing your annual return by hundreds of pounds; compare current rates before your system is commissioned.
- Do not over-spec panels on a simple roof. On an unshaded south-facing roof, money is better spent on a longer inverter warranty than on flagship panels.
Regional Price Differences
Across our 519-town pricing dataset, the North East, Yorkshire and the North West are consistently the cheapest regions for solar installation, while London and the South East run 20-30% above the cheapest regions, driven almost entirely by labour and access costs. A 4kWp system quoted at £4,275 in the North East can comfortably reach £5,175 or more in outer London.
There is a partial offset: southern England receives more solar irradiance, so the same system generates roughly 5-10% more in Cornwall or Kent than in central Scotland. Higher install prices in the South are therefore softened, but not cancelled, by higher generation. Wherever you are, the spread between local installers is usually bigger than the regional premium itself, which is why comparing at least three quotes matters more than your postcode.
FAQs
A 10kW (10kWp) solar system costs around £8,300-£10,500 installed in the UK in 2026. That buys roughly 23-24 panels at 430W each, needs about 47m² of roof, and should generate 8,500-9,500 kWh a year from a south-facing roof. Expect annual savings of roughly £1,190-£2,090 depending on how much you self-consume and your export rate, for payback in about 5-8 years. On a single-phase supply a 10kW system needs G99 DNO approval and is often export-limited, so allow extra time for paperwork. Adding a 10kWh battery takes the total to roughly £11,500-£15,300.
Ten modern 430W panels make a 4.3kWp system, which costs about £4,400-£5,400 installed in 2026, including scaffolding, inverter, labour and MCS certification. Expect around 3,650-4,100 kWh of generation a year from a south-facing roof. This sits just above the classic 4kWp system at £4,275-£5,175, which is the most commonly quoted domestic size in the UK.
Twelve 430W panels give you roughly a 5.2kWp system costing about £5,100-£6,300 installed in 2026. You need around 24m² of roof space, and generation is typically 4,400-4,950 kWh a year south-facing. This is a strong size for a 3-4 bed home with above-average electricity use, and it pairs well with a 5-10kWh battery.
A 16 panel solar system using 430W panels is about 6.9kWp and costs roughly £6,300-£7,900 installed in 2026. It needs around 31m² of roof and generates about 5,850-6,550 kWh a year on a south-facing roof, comfortably covering a high-usage household or a home with an EV charger. Per kWp it is noticeably cheaper than smaller systems because the fixed costs are spread over more panels.
Twenty-four 430W panels make a large 10.3kWp array costing about £8,500-£10,800 installed in 2026. You need roughly 47m² of unshaded roof, and generation is around 8,750-9,800 kWh a year south-facing. At this size your installer must obtain G99 approval from the DNO, and on a single-phase supply the system will usually be export-limited unless you upgrade to three-phase.
A single 430-470W residential panel costs about £100-£220 as hardware. Installed as part of a full system, the effective cost is roughly £490-£610 per panel on a small 7-panel array, falling to £340-£440 per panel on a 28-panel array, because scaffolding, the inverter, labour and certification are fixed costs. Adding one panel to an existing system typically costs £300-£500 or more once access and electrician time are counted, so single-panel jobs rarely make financial sense.
Almost everyone asking this means a 10kWh battery (kW measures power, kWh measures stored energy). A 10kWh usable battery costs about £4,000-£5,800 as a standalone retrofit in 2026, or £3,200-£4,800 when fitted at the same time as a new solar system, where it shares the hybrid inverter and labour. Batteries are zero-rated for VAT, including standalone retrofits.
A 5kWh usable battery costs around £2,500-£4,000 fitted as a standalone retrofit, or £1,800-£3,000 when installed alongside new solar panels. It suits smaller households and 3-4kWp systems; if you run a heat pump or charge an EV overnight, a 10kWh or 13.5kWh unit is usually the better fit.
A 50kW system is a commercial installation, typically £35,000-£45,000 (£700-£900 per kWp) for a straightforward rooftop project in 2026. Every job is bespoke: it needs a structural survey, shading study, G99 grid application and often planning permission, so treat any firm price quoted before that work as a guess. Get at least three bespoke quotes from commercial MCS installers.
Around £65,000-£85,000 installed (£650-£850 per kWp) for a typical commercial rooftop in 2026, generating roughly 85,000-95,000 kWh a year. Costs vary widely with roof structure, grid connection capacity and whether network reinforcement is needed, so a bespoke design and quote is essential rather than a rate-card price.
Divide your annual electricity use in kWh by roughly 900 to get a starting system size in kWp. A 2-3 bed home using around 2,700 kWh suits 3-4kWp; a 3-4 bed home using 3,500-4,500 kWh suits 4-6kWp; and homes with a heat pump or EV, using 6,000+ kWh, justify 8-12kWp with a battery. Bigger is cheaper per kWp, but only pays off if you can use or export the extra power at a decent rate.
Planning permission is rarely needed: domestic solar is usually permitted development, with exceptions for listed buildings, some conservation areas and flats. The approval that does matter is from your electricity network operator: systems up to 3.68kW of inverter output per phase just need a G98 notification after installation, while anything larger, including most 6kW+ systems and all 10-12kW arrays on single-phase supplies, needs G99 approval before switch-on. Your installer handles both.
Ready to Price Up Your Solar System?
Whether you are weighing up 10 panels or 24, the fastest way to a real number is comparing quotes from MCS-certified installers who have seen your roof. Tell us about your home once and get up to three free, no-obligation quotes to compare against the 2026 prices on this page.
Get My 3 Free Quotes →