| Expected output (PVGIS) | 1,029 kWh a year per 1 kWp, Cardiff, 35 degree pitch, south-facing, 14% losses |
|---|---|
| Roof panels in Wales | Should project no more than 200 mm and not rise above the ridgeline (Welsh Government) |
| Free help | Nest can offer solar panels to eligible households that own or privately rent their home |
| Interest-free loans | Green Homes Wales, managed by the Development Bank of Wales, lists solar panels among its measures |
| Export payments | The Smart Export Guarantee covers installations located in Great Britain |
What a Welsh roof can produce
The European Commission’s PVGIS tool is a neutral yardstick. For Cardiff, with a 35 degree pitch, south-facing panels and 14% system losses, it returns about 1,029 kWh a year for each 1 kWp. That is very close to the figure for central London on the same inputs.
Your roof will differ, so use the number to test a claim rather than to predict your bill. Hills, trees and the pitch of older terraces can all change the result, because each one alters shade or angle. So ask every installer to state the kWh it expects and the shading it assumed.
Panel count matters too, since a bigger array costs more but may not match your use. Our guide on how many panels you need shows how to size a system to your home instead of to the roof.
Planning rules in Wales
Wales follows its own planning guidance. The Welsh Government says roof and wall-mounted panels on a single dwelling are generally permitted development. It sets out four expectations, and they are easy to check on a quote.
- Panels should be sited to limit the effect on the building’s appearance and on the area’s amenity.
- They should not go above the ridgeline.
- They should project no more than 200 mm from the roof or wall.
- They should come off as soon as possible when no longer needed.
A listed building is different. The Welsh Government says installation requires planning permission and is likely to need listed building consent. In conservation areas and World Heritage Sites, consent is needed for panels on a principal or side wall that is visible from the highway.
Flat roofs have their own limits. Panels cannot sit within 1 metre of the roof edge, and they cannot rise more than 1 metre above the roof plane. Our planning permission guide puts the national picture side by side, although Welsh guidance is the one that applies to your home.
Help with the cost
Wales offers more than one route, and each has its own rules, so read the official page before you sign a finance deal.
Nest
Nest is the Welsh Government’s home energy scheme, and it can recommend a package that includes solar panels. To qualify, you must own or privately rent your home. You must also receive a means-tested benefit or live in a low-income household.
Your home needs an energy rating of 54 (E) or less. Alternatively, a rating of 68 (D) or less can count when someone in the household has an eligible health condition. If you are unsure, Nest says you can still ask, because it can point you to other schemes.
Green Homes Wales
Green Homes Wales gives interest-free loans and free expert help. It lists solar panels among its measures, alongside loft insulation and heat pumps. The Development Bank of Wales manages it for the Welsh Government. Terms change, so check the current page.
For wider context, the grants and VAT guide explains what applies across the UK. Be wary of any “free solar” offer that does not name Nest or another official scheme, since Nest sets clear eligibility rules.
Connecting to the grid
Ofgem’s licensee list names National Grid Electricity Distribution (South Wales) Plc as a Welsh distribution licensee. That covers the south. The ENA guide lists SP Energy Networks for Cheshire, Merseyside and North Wales, so another operator may serve your postcode in the north. Ask your installer which one applies.
National Grid’s G98 route is a fit and notify process. You notify within 28 days of commissioning using its online form. Our guide to G98 and G99 applications explains when a larger system needs approval first.
Exports and resale
The Smart Export Guarantee covers installations located in Great Britain, which includes Wales. Licensed suppliers set their own rates, although a rate must always be above zero. Compare offers before you pick one.
Panels can affect a sale, because a buyer inherits the system. Read our note on selling a house with solar panels before you agree to a lease or finance deal. Insurance is another question, so see our guide to solar panels and home insurance and tell your insurer before the work starts.
Protecting your deposit
If a quote asks for money upfront, check how the deposit is protected, since it is your money at risk until the work is done. Our guide to deposit and payment checks lists the questions to ask. Prices vary, so get written quotes.
Also keep every message with the installer. While a verbal promise is easy to forget, an email is proof of what the installer agreed.
Comparing your quotes
Use the quote comparison checklist to match scope, equipment and warranties. Two totals can look alike because one quote leaves out scaffolding or the grid notice, so compare line by line.
Scotland and Northern Ireland handle planning and support differently. See how Scottish funding and rules differ and what Northern Ireland households can claim if you own property there.
When you are ready, the free enquiry form can match you with MCS-certified installers.