Based on current MCS data, a typical 4kW solar system in Wales costs around £6,000 installed which is slightly below the UK average of £7,279, making South Wales one of the better-value regions in the country for solar installation.

As a rough guide for 2026:

• Small home (1–2 bed): 3kW system — around £4,500

• Average home (3 bed): 4kW system — around £6,000

• Larger home (4+ bed): 6kW system — around £7,500–£8,500

All prices include 0% VAT, which currently applies to residential solar installations until at least March 2027. Adding a battery storage system typically adds £3,000–£5,500 on top. The best way to get an accurate figure for your home is to book a free survey as we visit your property, assess your roof and energy use, and give you a precise quote rather than a generic estimate.

The right number depends on your energy use and available roof space, but as a starting point:

• A 3-bedroom home typically needs a 4kW system which is around 9 - 10 panels at current panel sizes (400–450W each)

• A 4–5 bedroom home may need a larger system. Let’s say 6kW system so around 13 to 15 panels

We size every system based on your actual electricity bills and roof orientation, not a one-size-fits-all formula. A south-facing roof in South Wales will generate significantly more than the same sized system on a north-facing roof so the design matters as much as the number of panels. We'll work all of this out during your free survey.

A typical home solar installation takes one day. Our in-house teams (not subcontractors) will arrive in the morning, fit the panels, install the inverter, connect everything up, and commission the system before they leave, including setting up your monitoring app so you can see what your panels are generating from day one.

If you're adding battery storage at the same time, this is usually still a one-day job. Retrofitting a battery to an existing system is typically done in half a day.

There may be other aspects to your installation which can take longer like scaffolding set up and take-down and applying to for a G98/99.

It’s hard to say without looking at your actual property but here’s some averages:

The average cost of a 4kW solar system in Wales is £6,000 as of March 2026, with a cost per kW of £1,507 , the lowest of any UK nation. South Wales also has the best overall Return On Investment (ROI) of any UK region, with a 12.4-year payback period (and falling as energy prices rise!) and £181 per year in Smart Export Guarantee earnings.

Welsh homeowners have access to several schemes that can significantly reduce upfront costs:

• Green Homes Wales loan — interest-free loan of up to £25,000 from the Development Bank of Wales, specifically for Welsh homeowners. Tewdric Energy is an approved installer. New applications re-open in April 2026.

• 0% VAT — there is currently no VAT on residential solar panel installations, saving you around £800–£1,800 compared to the standard rate. This is confirmed until at least March 2027.

• Smart Export Guarantee (SEG) — not a grant, but a payment from your energy supplier for surplus electricity you export to the grid. Available to all MCS-accredited installations. We can help you set this up.

See our full funding and grants guide for more detail on each scheme.

Tewdric Energy is accredited by MCS (Microgeneration Certification Scheme), RECC, NAPIT, and TrustMark for solar panel installations. MCS accreditation is the industry standard and is required for your installation to qualify for the Smart Export Guarantee and the Green Homes Wales loan scheme.

We are also an approved Green Homes Wales installer — one of a limited number of South Wales companies authorised to carry out installations funded through the Development Bank of Wales scheme.

Our own in-house teams carry out all installations. We don't use subcontractors as standard and if we do (at peak times to reduce the delay to installs), they will be managed by an Tewdric employee on site.

The same people who design your system will be on site to install it, and they'll stay until everything is commissioned, your monitoring is set up, and you're happy with how it all works.

We have offices in Chepstow and the Vale of Glamorgan so our teams can reach customers across South Wales and the South West quickly.

You can add battery storage later as a retrofit. It doesn't have to be installed at the same time as your panels. That said, installing both together is usually more cost-effective, as the scaffolding and electrical work is already in place.

If you already have solar panels from another installer, we can assess your existing system and recommend a compatible battery. SigEnergy batteries, our preferred system, are designed to work with most inverter brands. We'll check compatibility during a survey visit.