This guide uses official government figures to explain what home solar panels cost in Great Britain. The Department for Energy Security and Net Zero (DESNZ) published its latest solar cost data on 28 May 2026. The data covers installations from April 2025 to March 2026, drawn from the MCS Installation Database. You can use it to sense-check quotes and estimate a rough budget before you ask installers to visit.
For the broader overview, read our guide: Install Solar Panels Cost Breakdown for UK Homeowners.
Independent guide. We are not a lender or a government body. Always check current scheme rules with the official provider.
1. Read the official cost per kW figures
DESNZ reports solar costs per kilowatt (kW) of system size, based on Declared Net Capacity. The figures include equipment, installation, grid connection and VAT. They exclude batteries, extended warranties and other works. The median is the middle value, so half of installations cost more and half cost less. The mean is the simple average, which a few expensive installations can pull upwards.
| System size | Median cost per kW | Mean cost per kW |
|---|---|---|
| 0–4 kW | £1,780 | £2,008 |
| 4–10 kW | £1,697 | £1,770 |
| 10–50 kW | £1,262 | Not used on this page |
Larger systems cost less per kW, because fixed costs such as scaffolding and connection are spread across more panels. For 0–4 kW systems, domestic retrofits had a mean of £2,228 per kW, while new-build homes had a mean of £1,599 per kW. DESNZ analysed 265,682 installations, a record number. After adjusting for inflation, the median cost per kW for 0–4 kW and 4–10 kW systems was the lowest on record. The next release is due on 27 May 2027.
2. Calculate a rough figure for your system
A rough figure helps you judge whether a quote sits in a sensible range. It is arithmetic based on official medians, not a price for your roof. Your installer sets the real system size after a survey. Use the steps below to build your own estimate.
- Ask an MCS installer, or check your quote, for the proposed system size in kW.
- Find the matching size band in the official table above.
- Multiply the system size by the median cost per kW for that band.
- Add any battery, roof repairs or extra works separately, because the official figure excludes them.
- Compare the result with the itemised totals on two or three written quotes.
Illustrative arithmetic, not a quote: a 4 kW system × £1,780 per kW ≈ £7,120. A quote well above or below your rough figure is a reason to ask questions, not proof of a problem. Ask the installer to explain the system size, equipment and access costs behind the total.
3. Add what the official figure leaves out
The official cost per kW covers a standard installation, so your total cost of ownership is usually wider. Some homes need extra work before panels go on, and every system has costs over its life. List these items early so they do not surprise you later. The items below are common, but your survey decides which apply.
- A battery, which DESNZ excludes from its solar cost figures.
- Scaffolding that differs from a standard job, such as for tall or hard-to-reach roofs.
- Roof repairs needed before fitting.
- Inverter replacement during the system's life.
- Monitoring, maintenance and insurance changes.
Check funding before you commit, because grants and loans change what you pay upfront. The Warm Homes Loan has a solar maximum of £15,000, though full eligibility and application details are not yet confirmed. Eligible low-income households in England can ask their council about the Warm Homes: Local Grant.
Checklist
- I know my proposed system size in kW.
- I have calculated a rough figure from the official median.
- I have listed extras the official figure excludes.
- I have checked grants and loans before committing.
- I have two or three written MCS quotes to compare.
Frequently asked questions
Is the official cost per kW the price I will pay?
No. It is a median from past installations across Great Britain. Your price depends on your roof, access, equipment and any extra works.
Does the official figure include my battery?
No. DESNZ excludes batteries, extended warranties and other works. Ask installers to price a battery as a separate line.
Why is my quote higher per kW than the median?
Smaller systems, difficult access and extra works raise the cost per kW. Ask the installer to itemise the quote so you can see the cause.
Does VAT appear in the official figures?
Yes. The DESNZ figures include equipment, installation, connection and VAT.
When will the figures be updated?
DESNZ plans its next release on 27 May 2027. We will review this page when new figures appear.
So you can judge solar quotes against official figures and budget for the extras they leave out.
WHLS Editorial Team
Our editorial team writes independent, plain-English guides on home energy finance. We review guides when scheme rules change.
References
- DESNZ – Small scale solar PV cost data (opens in a new tab)
- GOV.UK – Notice of approved grant categories and values for the Boiler Upgrade Scheme (opens in a new tab)
- Energy Saving Trust – Boiler Upgrade Scheme (opens in a new tab)
- MoneySavingExpert – Warm Homes Loan Scheme news (October 2026) (opens in a new tab)
- Financial Conduct Authority – Financial Services Register (opens in a new tab)
- MCS – Find an installer (opens in a new tab)
- Energy Saving Trust – Warm Homes: Local Grant guide (opens in a new tab)
