Our Editorial Policy: Sources, Reviews, Updates and Corrections
Our editorial policy sets how every figure on Solar Panel Cost Calculator is sourced, dated, reviewed and corrected. Each sourced figure has to carry one named source and the date we checked it. The Solar Panel Cost Calculator Editorial Team writes the pages. The policy covers every page on this site and the calculator our figures feed.
| Rule | What it means for you |
|---|---|
| Sources | Primary sources come first: Ofgem, gov.uk, DESNZ, HMRC, MCS and the European Commission Joint Research Centre. |
| Corrections | Email editorial@solarpanelcostcalculator.uk. |
Who Writes and Who Checks Our Pages
The Solar Panel Cost Calculator Editorial Team writes our pages, and a named technical reviewer checks technical content before a page says it was reviewed.
Chris Roberts has agreed to act as our technical reviewer. A page shows his review line only when our review records hold his review of that page. Those records rest on the site owner's statement of 12 November 2026 that he had reviewed the site's pages. Some pages, this one included, have no record and carry no review line. The table sets out the two roles.
| Role | What the role does | What the role does not do |
|---|---|---|
| Editorial team | Writes our pages, drafted with AI assistance. | It does not set prices. Sourced prices come from the datasets named on this page. |
| Technical reviewer | Checks formulas, system sizing and technical claims on a page before that page shows a review line. | The reviewer does not set prices or write the pages. |
A review line names the reviewer and gives the date of the review, with a link to his profile once that page is published.
Where Our Figures Come From: Our Source Standards
We take each sourced figure from the body that publishes it, or say it is our calculation, and we name that source and its date. The table ranks the four types of source we use, from first choice to last.
| Order | Type of source | Examples | How we use it |
|---|---|---|---|
| 1 | Primary data and rules | Ofgem (price cap, Smart Export Guarantee rules); the Department for Energy Security and Net Zero (DESNZ) "Solar PV cost data"; HM Revenue and Customs (HMRC) VAT Notice 708/6; gov.uk scheme guidance; the Microgeneration Certification Scheme (MCS); PVGIS from the European Commission Joint Research Centre | We cite these directly. |
| 2 | Advice and reports from public bodies | Energy Saving Trust | We cite them by name and date when no primary figure exists. |
| 3 | A company's page about its own facts | An energy supplier's page for its own export rate; a maker's datasheet for a battery's usable capacity | We cite the page with the date we read it. |
| 4 | Press, retailer and comparison sites | News reports and price roundups | We use them to find a fact and trace it to its primary source where one exists. |
Four rules apply to every source in the table:
- Each sourced figure names its source and date.
- An average names its dataset and its period.
- An estimate is called an estimate, never a quote or a prediction.
- A "this month" figure appears only when the source publishes one.
On our service-cost pages (cleaning, bird proofing, inverter replacement, maintenance and repairs) we may print a price range from a trade or price-guide site once we have checked it on that site. We name the site, give the date we read it, and never present it as the one price.
The formulas that turn sourced figures into an estimate are set out in our methodology. Each dataset is logged with its date under sources and data dates.
What "Last Updated" and "Price-Checked" Mean
"Last updated" changes only when we change a page.
- Last updated
- The date a figure, a rule or the meaning of the text last changed. A spelling or layout fix does not move it.
- Changed on
- A note beside a corrected figure, with the date of the correction.
Two figures change on known dates. The electricity unit rate follows the Ofgem price cap, 26.32p per kWh for 1 October to 31 December 2026, so pages read it from the data files. The 0% VAT figures for solar panels and batteries end on 31 March 2027, and the 5% figures replace them on 1 April 2027.
How Often We Review Each Type of Page
The Ofgem price cap changes on 1 January, 1 April, 1 July and 1 October. We have set no fixed review calendar. The table gives, for each of seven page types, what we check and the event that changes those figures, which is when that page needs a new check.
| Page type | What we check | Needs a new check when |
|---|---|---|
| Home page calculator and cost pages | Cost per kW, unit rate, export rate, VAT | DESNZ publishes its yearly Solar PV cost data (latest release: 28 May 2026) |
| Battery pages | Battery prices, usable capacity, whether the maker is still trading | A maker enters administration, as GivEnergy did on 9 April 2026 |
| Export tariff pages | Each supplier's export rate and terms | A supplier announces a change |
| Price cap news | The new rate and its effect on savings | Ofgem announces each new cap; it says the cap for 1 January to 31 March 2027 will be announced by 25 November 2026 |
| Grant and scheme pages | Eligibility, dates, caps and official links | A rule changes. ECO4 ends for new measures on 31 December 2026; the Warm Homes: Local Grant runs to 31 March 2028 |
| VAT pages | The rate and its end date | The rate changes on 1 April 2027 |
| Plug-in solar pages | The legal limits in Great Britain, where plug-in solar has been legal since 27 August 2026 | A rule changes |
A change to the page updates the Last updated date.
How We Stay Independent of Leads 2 Trade
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.
That payment is a commercial tie. Independent here means three things you can check:
- Our calculator can return a Poor fit verdict, and then we do not offer a survey.
- This page and our other policy pages carry no survey form.
- Our sourced figures come from named datasets, and no figure changes because of who pays us.
The full arrangement is on our page about how we are paid for survey requests.
How We Handle Brands, Products and Schemes
Five rules apply to brands, products and schemes:
- Sourced prices come from public sources and carry the date we checked them.
- Brand comparisons rank on a stated measure, such as cost per kWh, never on a deal.
- A company in difficulty is reported with dated facts and sources only, with no buying link and no guesses about other firms.
- A scheme page gives the official link and the eligibility rules first, and says a scheme funds solar only with the scheme's name and who qualifies.
- We explain finance and do not arrange credit: no page on this site offers a loan or takes a loan application.
What We Never Publish
Some things never appear on this site, whoever asks. The table lists eight of them, each with its reason.
| We never publish | Why |
|---|---|
| Reviews, star ratings, testimonials or user counts we cannot verify | A claim nobody can check is not evidence. |
| Urgency other than a real, dated deadline | We show a deadline with its date and source, such as 0% VAT ending on 31 March 2027 (HMRC). No countdowns, no "prices rising". |
| The phrase "free solar" without a named scheme and who qualifies | Free applies to a scheme and its eligibility, not to solar in general. |
| "Guaranteed savings", "zero bills", or "pays for itself" without the years | A saving depends on your home, your use and your tariff. |
| Any claim that we are an installer, MCS-certified, a lender, a government body or "official" | We are none of these. |
| The phrase "trusted installers" | We do not vet installers. MCS registration is each installer's own. |
| A figure with no source | A sourced figure has to trace to a named source and its date, and a figure we work out is called our calculation or an estimate, whoever or whatever drafted the sentence around it. |
| A green claim beyond one carbon figure with its method and source | A general green claim cannot be checked. |
Reviews and Testimonials
We publish no customer reviews or testimonials.
How We Use AI
We draft our pages with AI assistance. Each sourced figure comes from a named source, not from an AI tool. Our build checks fail when a number of three or more digits in a page's main text, other than a year, matches no figure in our data files.
How to Report an Error
If you think a figure or a fact is wrong, email editorial@solarpanelcostcalculator.uk. Three details help us find it:
- The address of the page.
- The figure or the sentence.
- The source you think is right, if you have one.
We reply within 2 working days.
How We Correct Mistakes
The table shows what we do for one kind of error.
| What was wrong | What we do | Where you see it |
|---|---|---|
| Spelling, grammar or layout | Fix it without an entry. | The Last updated date does not move |
If You Disagree With Our Answer
If you disagree with our answer to your report, email hello@solarpanelcostcalculator.uk with the subject "Complaint". We acknowledge a complaint within 2 working days and reply in full within 2 working days.
Two kinds of complaint follow their own route:
- A dispute with an installer goes to that installer first. We cannot resolve it.
- A complaint about how we handled your personal data comes to us first, at privacy@solarpanelcostcalculator.uk. Our privacy notice sets out the rest of that route.
Changes to This Policy
This is version 1.0 of our editorial policy. When we change a rule here, we update the date on this page.