Solar panels in Swansea: roofs, grid and planning rules

Houses, terraces and flats

If you live in a terrace or a flat, the first question is about the roof itself. Who owns it, how much of it faces the sun, and can the structure carry the load? Our post on solar panels for terraced houses and flats covers roof space, leasehold consent and shared roofs.

However, a survey should answer the structural question. MIS 3002 says a suitably competent person must check the roof structure can carry the loads. Ask to see that check in your paperwork.

If you rent or lease, speak to your landlord or freeholder before you spend time on quotes. Their agreement is a separate step from planning. It can take longer, because owners may be slow to reply, so start early.

Solar output in Swansea

The European Commission’s PVGIS model gives about 1,014 kWh a year for each kWp in Swansea. That is for a south-facing roof at 35 degrees, with PVGIS’s default 14% losses. The best tilt in the model is 39 degrees, at about 1,016 kWh per kWp.

For example, a 4.5 kWp system would make around 4.5 x 1,014, or about 4,563 kWh a year. That is a modelled estimate rather than a promise. Real output depends on weather, kit and shade.

A terraced roof may face east or west rather than south. Such a roof makes less in total, but it can suit people who use power in the morning and evening. Shade is the other risk, since a taller neighbour or a tree can hit a small roof hard.

Panels also need a little care over the years, because dirt and bird nests can cut output. Our post on solar panel maintenance and cleaning explains monitoring, inspections and warranties.

Value is worth a look too. Ofgem’s price cap from October to December 2026 averages 26.32p per kWh for electricity, though your region and tariff may differ. Because power you use from your own roof is power you do not buy, it saves money. Check your own bill before you judge any claim about savings.

Grid connection

For South Wales, our data names National Grid Electricity Distribution. The operator must hear about every system, and under MCS rules your installer does that.

The size of the system sets the route. Specifically, installs up to and including 16 A per phase follow G98, and bigger ones follow G99. MCS counts all generators together, so a battery can change the answer.

For G98, a National Grid page describes notice within 28 days of commissioning. Ask for a written timeline, since G99 usually takes longer.

Planning rules in Wales

Wales has its own rules, so England’s August 2026 changes do not apply. The Welsh Government’s page on planning permission for solar panels sets two tests. Panels should project no more than 200mm from the roof or wall, and they should stay below the ridgeline.

In contrast, listed buildings need planning permission and are likely to need listed building consent. In conservation areas and World Heritage Sites, panels on principal or side walls seen from the highway need planning consent. We have not checked local maps, so we cannot say which streets are affected.

The planning authority is the City and County of Swansea Council. Ask it about your address, especially if you live in a flat or an older terrace. A short query now is cheaper than a refused scheme. Our post on planning permission for solar panels compares the rules in England, Scotland and Wales.

Picking an installer

Look for MCS certification, the UK quality mark for small-scale renewables. GOV.UK says you need MCS, or an equivalent scheme, to claim Smart Export Guarantee payments. You can search the MCS site to check a business.

Then ask about the Renewable Energy Consumer Code. RECC members must insure deposits, stage payments and workmanship warranties. That cover matters if a firm stops trading.

Welsh households can also ask about Nest, which can recommend a package that could include solar panels. Because Nest advisers check eligibility, do not assume you qualify.

Collect at least three quotes, because prices and designs vary. Compare kWp, equipment, warranty and who handles the paperwork. Our solar panel installation guide lists what a full quote covers. Our solar panel costs guide shows what government data says about price.

Meanwhile, for a nearby comparison, read our page on solar panels in Cardiff. When you are ready, you can ask for quotes. With your consent, we will pass your enquiry to an MCS-certified installer.