Sources, and what each one gave us
| Source | What we used it for | Edition and date |
|---|---|---|
| PVGIS 5.3 photovoltaic estimates, European Commission Joint Research Centre | Solar output for every map square, area, roof direction and pitch, month by month and for vertical balcony panels | Pulled through the PVGIS 5.3 web service on 3 November 2026: SARAH3 satellite data 2005–2023, 1 kW of crystalline panels, 14% losses, terrain horizon. |
| ONS Open Geography Portal: local authority district boundaries (December 2024) | The outline of the borough on the peninsula map | Local Authority Districts (December 2024) Boundaries UK BGC, Wirral E08000015. Open Government Licence; contains OS data © Crown copyright and database right 2024. |
| Census 2021 TS044, accommodation type (Nomis) | House types: semi-detached 41.6%, terraced 23.5%, detached 17.4%, flats 17.5% of households | Census 2021, released January 2023. |
| ONS: how life has changed in Wirral, Census 2021 | Tenure: 65.0% of households own their home; private renting 18.9% | Census 2021. |
| VOA: Council Tax stock of properties 2026 | Build period and property type: 47.7% of homes built before 1945, 7.8% bungalows | Council Tax stock of properties, data at 31 March 2026, published 24 September 2026. |
| ONS: energy efficiency of housing in England and Wales (EPC band C or above by area) | 44.3% of Wirral homes with an EPC rated A to C | EPCs lodged April 2015 to March 2025, released October 2025; ONS has since discontinued the series. |
| DESNZ: renewable electricity by local authority, 2014 to 2025 | 5,382 solar installations in Wirral at the end of 2025 | Published 29 September 2026; 2025 figures provisional. |
| DESNZ: solar PV cost data (2025/26) | Average installed cost per kW for home systems | Solar PV cost data, 2025/26 domestic means. |
| Wirral Council: conservation areas | The 26 conservation areas | Wirral Council, read 3 November 2026. |
| Wirral Council: solar panels and planning permission | Wirral Council's guidance on panels and planning, and the Bromborough Pool Article 4 direction | Read 3 November 2026. |
| Wirral Council: listed buildings | Over 1,900 listed buildings | Read 3 November 2026. |
| Wirral Council: Port Sunlight Local Listed Building Consent Order | What Port Sunlight's consent order covers | Order for 2025 to 2040, read 3 November 2026. |
| The Town and Country Planning (General Permitted Development) (England) Order 2015, Schedule 2, Part 14 | Permitted development rules for solar | As amended by SI 2026/896 from 27 August 2026. |
| Liverpool City Region Combined Authority: Warm Homes: Local Grant | Who runs the Warm Homes: Local Grant in Wirral and who qualifies | Read 3 November 2026. |
| LCRCA: fourth round of the group-buying scheme for solar panels (27 Oct 2025) | Solar Together rounds and results | With the earlier releases for rounds 1 to 3. |
| SP Energy Networks: connecting to the grid | The network operator and the G98 and G99 thresholds | Read 3 November 2026. |
| Ofgem: energy price cap unit rates and standing charges | Electricity unit rate used in our sums: 26.32p per kWh | Price cap for 1 October to 31 December 2026, GB average, direct debit. |
| Ofgem: typical domestic consumption values, decision (May 2026) | Typical household use: 2,500 kWh a year | Ofgem typical domestic consumption values, in use from July 2026. |
| HMRC VAT Notice 708/6: the zero rate on installed solar panels and batteries | 0% VAT on installed solar and batteries until 31 March 2027 | HMRC VAT Notice 708/6. |
| Met Office: Hawarden Airport climate averages 1991–2020 | Nearest sunshine record: about 1,570 hours a year | Met Office 1991–2020 averages for Hawarden Airport. |
| Wirral Council: Wirral Spatial Portrait 2020 (local plan evidence, draft) | Coastline length, land area and the housing areas of the borough | Wirral Spatial Portrait 2020, local plan evidence (draft). |
What is our own work
Three things on the site are calculations we made from the sources above, rather than figures copied from them.
- The peninsula map. We drew the outline from the ONS boundary file and asked PVGIS for the output of 1 kW of south-facing panels at points 0.025° apart across it. Each square on the map is one of those answers. The six areas are our own grouping of familiar places; their ranges are the squares whose centres fall on land in each area.
- Prices by system size. We multiplied the government's average cost per kW for home installs by each system size. These are averages across Great Britain, not Wirral prices.
- Year-one values. On the "is it worth it" page we multiplied PVGIS output by assumed shares used at home and the stated tariffs. The assumptions are written under the table and kept within the limits we set ourselves: no more than 75% of a household's use covered by panels alone, or 90% with a battery.
What we do not do
- We do not publish payback periods or promises about what panels will save you.
- No installer is reviewed, ranked or recommended on this site.
- We do not invent local facts. If we could not find a figure at a reliable source, such as the number of listed buildings in Port Sunlight, we say so rather than guess.
Keeping it current
Some figures change on a timetable: the price cap every three months (the next for January to March 2027 is due in late November 2026), the VAT relief on 1 April 2027, and the government's cost and installation statistics once a year. Council and city region pages change without notice. Each page shows the date its facts were last checked. If you notice something that has changed, please tell us through the form below; corrections are made to the page and the date updated.
Licences
Census, VOA, DESNZ, ONS and Ofgem material is used under the Open Government Licence. The map outline contains OS data © Crown copyright and database right 2024. PVGIS data is provided by the European Commission's Joint Research Centre. Council text is summarised, not copied.