BrightGridIf you've asked three different installers for a solar quote, you've probably had three very different answers. That's not because solar pricing is a mystery — it's because most quotes bundle together a lot of decisions the homeowner never actually sees. This guide breaks down exactly what you're paying for, what a fair 2026 UK price looks like by system size, and where the real savings (and the real risks of overpaying) actually sit.
Average solar panel costs by system size
Solar is priced in kWp (kilowatt-peak) — the maximum output the system can generate under ideal sunlight. Most UK homes fit somewhere between 3kWp and 6kWp, depending on roof size and household electricity use.
| System size | Typical panel count | Installed cost (2026) | Annual generation* |
|---|---|---|---|
| 3kWp | 7–8 panels | £5,500 – £6,800 | ~2,850 kWh |
| 4kWp | 9–10 panels | £6,800 – £8,200 | ~3,800 kWh |
| 5kWp | 11–13 panels | £7,900 – £9,600 | ~4,750 kWh |
| 6kWp | 14–15 panels | £9,200 – £11,000 | ~5,700 kWh |
*Based on South East England irradiance (~950 kWh per kWp per year) on a well-oriented, unshaded roof. Add a battery and you're typically looking at another £5,500–£8,000 depending on capacity — worth reading our separate guide on whether a battery is worth it before deciding.
What's actually in the price
A solar quote isn't just "panels." A fair, comprehensive price should include:
- Panels — the single biggest cost, roughly 40–50% of the total
- Inverter — converts DC panel output into usable AC electricity, 10–15%
- Mounting and roof fixings — varies significantly by roof type
- Scaffolding — often quoted separately, ask if it's already included
- Cabling, isolators and consumer unit work
- DNO notification/application where required
- Building Regulations notification and Microgeneration Certification Scheme (MCS) paperwork
- Commissioning, monitoring app setup, and your warranty documentation
Watch for quotes that look too good to be true
A price significantly below the ranges above usually means scaffolding, MCS certification, or a proper DNO application has been left out — and will land on your final invoice as an 'extra.' Always ask for a fully itemised quote before signing anything.
What actually drives the price up or down
Roof complexity
A simple, single-pitch roof with good access is the cheapest to fit. Multiple roof faces, steep pitches, slate (versus tile), or a third storey all add labour time and scaffolding cost.
Panel and inverter quality
Tier-1 panels with 25-year performance warranties cost more upfront than budget alternatives, but degrade more slowly and are far more likely to still be covered by a warranty claim in year 15. This is one area where the cheapest option is rarely the best value over the system's lifetime.
String inverter vs hybrid inverter
If you might add a battery later, a hybrid inverter (which can manage both solar and battery) costs more now but avoids paying for a second inverter at retrofit time. If you're certain you'll never add storage, a standard string inverter is cheaper today.
Realistic payback periods
For a well-sized 4–5kWp system on a good roof, with self-consumption around 35–40% (solar only, no battery), payback typically lands between 7 and 10 years against current standard variable tariffs. Adding a battery raises self-consumption to 60–70%+, which increases annual savings but also increases the upfront cost — payback for solar-plus-battery systems is often similar in years, but the annual saving in pounds is considerably higher.
Panels are commonly warrantied to still perform at 80–87% of original output after 25 years, so a 7–10 year payback leaves 15+ years of largely free electricity afterwards.
How to make sure you're getting a fair quote
- Ask for the quote broken down by component, not just a single total
- Confirm whether scaffolding, DNO notification and MCS certification are included
- Check the panel and inverter warranty lengths in writing, not just verbally
- Ask what generation estimate the quote is based on, and whether it accounts for your actual roof's shading and orientation
- Get the installer's MCS certification number and check it's current
See your actual number, not an industry average
Our calculator models your real roof, usage and tariff — not a generic estimate — in under two minutes.
Check Your SavingsFrequently asked questions
Is 2026 a good time to install solar panels in the UK?
Panel prices have fallen significantly over the past decade while electricity prices have risen, which has shortened typical payback periods. Current smart export tariffs also make solar more valuable than it was five years ago, even without a battery.
Do I need planning permission for solar panels?
Most homes install under permitted development rights. Listed buildings, some conservation areas, and panels that protrude unusually far from the roofline may need consent — a proper survey will confirm this before you commit.
How long do solar panels actually last?
Most manufacturers warranty panels for 25 years of performance, typically guaranteeing at least 80–87% of original output at that point. Physically, panels often keep generating well beyond their warranty period, just at gradually reduced efficiency.
Can I get solar panels installed with no upfront cost?
Finance options exist through third-party finance partners, spreading the cost over several years subject to eligibility and affordability checks. This isn't 'free' — you're paying interest — but it can make sense if it lets you install now rather than saving for years first.
Marcus Webb
Head of Engineering at BrightGrid Energy
