Short answer: the Energy Saving Trust gives about £7,600 for a typical 4.5kWp home system (fuel prices July 2026). Checkatrade (June 2026) gives about £6,000 for 3kW up to about £10,000 for 6kW. Get written quotes for your own roof before deciding.
Solar panel prices by system size
| System size | Roughly how many panels* | Typical installed cost |
|---|---|---|
| 3kW | 7 to 8 | About £6,000 |
| 4kW | 10 | About £8,000 |
| 4.5kWp | About 12 (EST) | About £7,600 (EST) |
| 5kW | 12 to 13 | About £9,000 |
| 6kW | 15 | About £10,000 |
Sources: Checkatrade cost guide, updated June 2026 (3, 4, 5 and 6kW); Energy Saving Trust, fuel prices July 2026 (4.5kWp). *Panel counts are our own arithmetic assuming 400W panels, except the EST row. Checked 25 Oct 2026.
Battery prices
| Battery size | Typical installed cost |
|---|---|
| 4kWh | About £4,000 |
| 5kWh | About £4,500 |
| 8kWh | About £8,000 |
| 10kWh | About £9,000 |
Source: Checkatrade battery cost guide, updated June 2026. The Energy Saving Trust gives £5,000 to £8,000. See battery storage.
What a quote should include
- Panels, inverter (or microinverters/optimisers), mounting and cabling
- Scaffolding or access equipment
- Electrical work, isolators and a generation meter
- Network operator notification (G98) or application (G99)
- MCS certificate and handover paperwork, which you'll need for SEG payments
- Warranties: panels, inverter, battery and workmanship, and any insurance-backed deposit or workmanship protection
What pushes the price up or down
- Access and scaffolding: three-storey homes, steep sites and shared access cost more.
- Roof type: slate, flat roofs and in-roof systems often cost more than tiled on-roof.
- Equipment choice: premium panels, optimisers and hybrid inverters add cost.
- Consumer unit upgrades if your fuse board needs replacing.
- Heritage constraints: listed building consent or planning in sensitive areas.
Running costs
Panels need little maintenance, but the Energy Saving Trust says inverters typically need replacing during the system's life (they suggest around 12 years). Factor that in when comparing quotes.
Payback
The Energy Saving Trust estimates payback of roughly 9 to 12 years for a typical system when you're paid for exports (fuel prices July 2026). Yours could be shorter or longer depending on your roof, how much you use yourself, your tariff and what you pay. Try our rough savings estimator, then ask installers to show their working.
Ways to reduce the cost
- 0% VAT on home solar and batteries until 31 March 2027 (HMRC Notice 708/6).
- Warm Homes: Local Grant or ECO4 if you qualify, and the Warm Homes Loan. See grants and funding.
- Get several quotes and compare like for like.
Cost questions
How much is a 4kW solar system?
How long do solar panels take to pay back?
Is there VAT on solar panels?
Sources
- Energy Saving Trust: Solar panels (fuel prices July 2026; checked 25 Oct 2026)
- Checkatrade: Cost of solar panel installation (updated June 2026; checked 25 Oct 2026)
- Checkatrade: Solar battery storage cost (updated June 2026; checked 25 Oct 2026)
- HMRC VAT Notice 708/6: energy-saving materials (checked 25 Oct 2026)
- Ofgem: Energy price cap unit rates and standing charges (1 Oct to 31 Dec 2026; checked 25 Oct 2026)
Figures change. We review this page regularly; if you spot something out of date, tell us through the form.