Disclaimer: Our Figures Are Estimates, Not Quotes or Financial Advice
Every figure on this site is an estimate: a figure worked out from your answers and from public data, with its source and date. It is not a quote, an offer or financial advice; only an installer can quote you a price, after a survey of your home.
The limits below apply to every calculator, table and page on this site.
An Estimate Is Not a Quote
An estimate tells you the likely cost, saving and payback for a home like yours; a quote is the price one installer offers for your home. The formulas behind the estimate are on the page that shows how we work out each estimate. The table sets the two side by side.
| Question | Our estimate | An installer's quote |
|---|---|---|
| Who gives it? | We do, from a formula | An MCS-registered installer |
| When? | Straight away, with no visit | After a survey of your home |
| What is it based on? | Your answers and dated public data | An inspection of your roof, shading and electrics |
| Is it an offer you can accept? | No | Yes, under the installer's terms |
| Does it change? | Yes, when the data or a tariff is updated | It holds for the period the installer states |
A typical cost is a middle figure: many homes pay more and many pay less.
Why a Survey Price Can Differ From Our Estimate
Things a survey finds that a calculator cannot see change the price. Six of them are common:
- Scaffolding and access to the roof.
- The condition of the roof and its covering, such as slate, tile or a flat roof.
- Shading from trees, chimneys or neighbouring buildings.
- A consumer unit or wiring that needs work.
- Network approval: a system above the G98 limit follows the G99 process, in which the Distribution Network Operator (DNO), the company that runs your local electricity network, is consulted before installation.
- The panels, inverter or battery you choose, and extras such as bird protection.
Only the installer who has seen your home can price these.
We Do Not Give Financial or Other Professional Advice
Our pages explain and estimate; they do not tell you what you should do with your money. Four kinds of advice sit outside what we do:
- Financial advice: we do not know your full finances. Consider independent advice before a large purchase or before you borrow.
- Credit: we do not arrange credit, introduce you to lenders or receive commission from lenders. If an installer offers finance, that agreement is between you and the installer or lender. Where we describe a loan scheme, such as the Warm Homes Loan Scheme (live since 27 October 2026), we explain it and nothing more.
- Legal, tax and planning advice: a listed building or a conservation area can change what is allowed, so check with your local planning authority.
- Structural and electrical advice: a qualified person must check your roof and your wiring. Do not go on the roof to check it yourself.
What Our Estimates Depend On
Each estimate is only as good as the answers you give and the data behind it. The table lists eight inputs, the source of each and how each can be wrong for your home.
| Input | What we use | Source and date | How it can be wrong |
|---|---|---|---|
| Yearly electricity use | 2,500 kWh if you do not enter your own | Ofgem typical domestic consumption value, medium electricity, from 1 July 2026 | Your real use can be far higher or lower, for example with an electric car or a heat pump |
| Electricity unit rate | 26.32p per kWh, or your own rate | Ofgem price cap for 1 October to 31 December 2026 | Your tariff can differ, and the cap changes every quarter |
| Export rate | 13p per kWh, or your own rate | Our calculation from Ofgem figures for the Smart Export Guarantee (SEG) | Rates vary by supplier and change |
| Installed cost per kW | The median cost for the size band of your system | Department for Energy Security and Net Zero (DESNZ), "Solar PV cost data", DNC basis, covering April 2025 to March 2026 | The price for your home depends on the survey |
| Generation | System size in kWp x a yearly yield figure x a shade factor. Today one UK yield figure stands in for a yield by postcode | The form of the MCS method | Real output varies from year to year with the weather |
| Roof direction, pitch and shade | Your answers | Direction and pitch shares are our calculation from PVGIS | The survey can find different shading |
| Battery size in kWh and self-use | Our model of how much solar power a home uses itself | The methodology page | Your daily pattern decides the real figure |
| VAT | 0% on home solar and batteries until 31 March 2027 | HM Revenue and Customs (HMRC), VAT Notice 708/6 | The rate is 5% from 1 April 2027 |
An input with no publishable source shows on the page as a gap, not as a number. The sources page lists every source and the date we checked it.
Prices, Tariffs and Scheme Rules Change
Energy prices, export rates, VAT and scheme rules change, and some change on fixed dates. The table gives six examples and where to check each one.
| What changes | How often or when | Check with |
|---|---|---|
| The Ofgem price cap | Every quarter | Ofgem |
| VAT on home solar and batteries | 0% ends on 31 March 2027; 5% applies from 1 April 2027 | HMRC, VAT Notice 708/6 |
| Export tariffs | When each supplier changes them | Your supplier |
| Grant schemes | When the government changes them. ECO4, for example, has a closing date for new measures of 31 December 2026 | gov.uk or your council |
| The Smart Export Guarantee and the Feed-in Tariff | The Feed-in Tariff closed to new applicants on 1 April 2019. The SEG has applied since 1 January 2020. The SEG is not the Feed-in Tariff | Ofgem |
| Plug-in solar rules | Legal to buy and use in Great Britain since 27 August 2026, up to 800 W from the micro-inverter | gov.uk |
A page with prices shows a Price-checked date. If that date is old, check the source before you rely on the figure.
We Are Not an Installer, and We Do Not Vet Installers
We are a calculator website. We do not install anything, and we do not check installers ourselves. We are not any of these five things:
- An installer.
- MCS, or a business that MCS has certified.
- A lender or a credit broker.
- The government or a government scheme.
- An energy supplier.
Leads 2 Trade, which arranges surveys for homeowners who ask, states that its installers must be MCS registered (Leads 2 Trade solar leads page, checked 7 November 2026). We do not check that ourselves. MCS registration is the installer's own certification, so check it with MCS before you sign.
Grants, Schemes and Who Qualifies
We explain schemes and who they are for, but only the scheme decides whether you qualify. Where we describe a scheme, we give its rules with the date we checked them and the official link. A household that may qualify applies through that official route, not through us. We never call solar panels free unless we name the scheme and who qualifies for it.
Brands, Products and Other Websites
Naming a brand or product is not a recommendation. We state facts and prices with the date we checked them, and nobody pays us to mention, rank or review a product. A dated fact can go out of date: GivEnergy Ltd, for example, has been in administration since 9 April 2026 (Companies House, checked 8 November 2026). We do not control other websites that we link to.
Carbon Figures
Where we show a carbon saving, it is one figure with its method and source. The calculator shows no carbon figure today. We do not describe solar as green or eco-friendly without a figure and a source behind the claim.
Mistakes, Corrections and Our Responsibility
If we get something wrong, we fix it, date the fix and record it in our changelog. To report an error, email editorial@solarpanelcostcalculator.uk with the page address and the figure. The editorial team compares the figure with its source and replies with what it found.
We take care to keep each figure sourced and dated, but an estimate can differ from what you pay or save. Do not decide on an estimate alone: get a survey and an installer's quote first. Nothing on this page takes away a right that the law gives you as a consumer. The full conditions for using this site are in our terms of use.
How We Are Paid
We are paid by Leads 2 Trade Limited when a homeowner we refer asks for a survey. You are never charged. It does not change our figures. The full arrangement is on the page about how Leads 2 Trade pays us.