7kW Solar System UK: Cost, Output & Payback (2026)
Quick Answer
A 7kW solar system in the UK costs £8,500–£10,500 installed in 2026, including 0% VAT for residential properties. It uses 14–26 panels, needs 23–42 m² of roof space, generates around 6,488 kWh/year, and pays back in 6–8 years.
Prices verified April 2026. Actual quotes vary with installer, brand and site conditions.
This guide covers everything that figure buys you — panels, roof space, annual output, payback and who this size actually suits.
7kW System at a Glance
| Typical cost | £8,500–£10,500 installed |
| Panels | 14–26 (depends on panel wattage) |
| Roof space | 23–42 m² |
| Annual output | ~6,488 kWh |
| Annual savings (self-use) | ~£993 |
| SEG export income | ~£535/yr |
| 25-year savings | ~£27,526 |
| Payback period | 6–8 years |
| Battery add-on | £5,000–£10,000 |
Who a 7kW System Suits
Larger homes with an EV, heat pump, or high daytime electricity use. Typically requires a G99 DNO application because inverter size exceeds 3.68kW.
Cost Breakdown
The headline £9,000 price for a 7kW system covers:
- Panels: 14–26 modules from a tier-1 manufacturer
- Inverter: string or hybrid inverter matched to system size
- Mounting & cabling: roof hooks, rails, DC/AC cabling, isolators
- Installation labour: typically 1–3 days for residential, longer for larger commercial
- DNO application: G98 notification or G99 approval — see below
- Commissioning & MCS certificate: required for SEG registration and 0% VAT
See our solar battery cost guide if you are considering adding storage. For a 7kW system, expect £5,000–£10,000 for a matched battery.
How Much Electricity Will It Produce?
A 7kW system in the UK produces around 6,488 kWh per year. Daily and monthly output varies with season — roughly 70% of generation arrives between April and September. Regional variation is significant:
- Southern England: upper end of the range (6,488 kWh)
- Midlands & Wales: ~90–95% of that figure
- Northern England: ~85–90%
- Scotland & Northern Ireland: ~80–85%
For context, the UK average household uses around 2,900 kWh per year — so a 7kW system produces 2.2× the typical home's electricity needs.
Savings & Payback
Savings come from two sources:
- Self-consumption: ~£993/year avoiding imported electricity at ~24–25p/kWh
- SEG export income: ~£535/year from surplus sold back to the grid
Over 25 years — the typical panel warranty — total savings reach roughly £27,526. That gives a payback period of 6–8 years at current prices. Electricity prices have risen faster than inflation historically, so real-world payback is often shorter than the modelled figure.
Pairing the system with a time-of-use tariff like Octopus Flux can lift export earnings significantly — see our best Octopus tariffs for solar guide.
DNO Approval (G98 vs G99)
G99 approval usually required — can add up to 45 working days to install timeline.
For full detail on the application process, timelines, and the nine UK DNO regions, see our DNO application guide.
Common Mistakes at This Size
- Underestimating DNO timelines — a G99 wait can push installation back by 6–9 weeks; factor this into any tariff-switching or EV-delivery dates
- Not sizing inverter to expected export limit — if the DNO caps export at 3.68kW, an 8kW inverter wastes generation mid-summer
- Choosing a battery brand that blocks Intelligent Octopus Flux — at this size, peak-export automation is worth ~£200–£400/year
- Assuming a 7kW system covers an EV charge — a typical overnight EV charge needs 20–40 kWh, more than a 7kW array makes in a full sunny day
Frequently Asked Questions
How much does a 7kW solar system cost in the UK?
A 7kW solar system costs £8,500–£10,500 installed in the UK in 2026, typically around £9,000. Prices include 0% VAT for residential installations and cover panels, inverter, mounting, labour, and DNO paperwork.
How many solar panels in a 7kW system?
A 7kW system uses 14–26 panels, depending on panel wattage (modern panels range from 300W to 500W each). Higher-wattage panels reduce the count and the roof space needed.
How much roof space does a 7kW system need?
A 7kW array needs 23–42 m² of unshaded roof space. Each panel covers roughly 1.6 m². South-facing pitched roofs between 30° and 45° deliver the best output in the UK.
How much electricity does a 7kW system produce per year?
A 7kW solar system in the UK generates around 6,488 kWh per year. Southern UK averages the high end; Scotland and Northern Ireland sit 10–15% lower. Actual output depends on orientation, shading, and panel quality.
What is the payback period for a 7kW system?
Typical payback for a 7kW system is 6–8 years, assuming current electricity prices around 24–25p/kWh and a fair SEG export rate. Battery pairing and time-of-use tariffs (e.g. Octopus Flux) can shorten payback further.
Compare Other System Sizes
| Size | Typical cost | Annual output | Payback | |
|---|---|---|---|---|
| 4kW | £5,500–£7,000 | ~3,800 kWh | 7–9 yrs | View → |
| 12kW | £12,000–£15,000 | ~11,122 kWh | 6–8 yrs | View → |
| 15kW | £17,000–£20,000 | ~13,903 kWh | 6–8 yrs | View → |
| 20kW | £22,000–£28,000 | ~18,537 kWh | 5–7 yrs | View → |
| 50kW | £55,000–£70,000 | ~46,343 kWh | 5–7 yrs | View → |
Get a Real Quote for Your Home
The easiest way to benchmark a 7kW system for your property is to compare quotes from two or three MCS-certified installers in your area. Pricing varies with roof complexity, panel brand, and whether you need scaffolding.
Sources
John Rooney is the founder of Solar Info and has been covering the UK solar energy market since 2023. He fact-checks all content against official MCS and Ofgem data and maintains relationships with MCS-certified installers across the UK.