What Solar Panels for a Garden Cost in 2026

Ground-mounted arrays

The PD-sized array — four panels, about 1.8kWp on a galvanised frame — costs £2,200–£3,500 professionally installed, including the inverter, the armoured cable run (the variable: every extra ten metres of trench adds £150–£300), DNO notification, and MCS certification. As professionally installed domestic solar it is zero-rated for VAT until 31 March 2027. Larger consented arrays price at £1,100–£1,400 per kWp, falling toward the lower bound as size spreads the fixed costs; a 4kWp garden array typically lands £4,800–£5,600 plus the planning application's £258. Self-build is possible for the frame and groundworks, but the grid connection and MCS sign-off (which unlocks Smart Export Guarantee income) keep an installer in the project — budget honestly for that.

Garden rooms and pergolas

An off-grid garden room system — 600–800W of panel, 5kWh of lithium, inverter — runs £1,800–£2,600 in parts, self-installed legally as a low-voltage island. The grid-tied alternative (mains to the building plus 1.5–3kWp MCS-installed on its roof) totals £3,100–£5,700 including the electrician's trench. Solar pergolas carry their structure in the price: £4,000–£6,500 installed for a quality 3m × 4m aluminium system around 2kWp, £7,000–£10,000 for larger bespoke builds. The pergola's fair comparison is against a conventional pergola plus a separate array — its marginal solar cost is £2,500–£4,000, which is the number to judge it on.

Lighting and small systems

A central-panel garden lighting system — 100W panel, 50Ah LiFePO4, controller, five quality path fittings, festoon run, cabling — costs £350–£500 self-installed and replaces an endless £4-stake subscription. Pond aeration kits with battery backing run £120–£250; a direct-drive greenhouse fan panel is under £60. These small systems buy capability rather than payback, and judging them on bill savings misses their point: they put light and water where the mains was never going to go.

Payback, the unglamorous way

A well-sited 1.8kWp ground array yields roughly 1,700kWh a year. The honest variable is how much you use directly: at 60% self-consumption with electricity at 26p/kWh and the rest exported at 8p under SEG, the array returns about £320 a year — a 7–10 year simple payback on the installed price, comfortably inside the panels' 25-year warranted life. Shift habits (or add a battery, £2,000+ and its own arithmetic) and self-consumption rises with the return. A 4kWp consented array improves the per-kW economics but exports a larger share, so its payback sits in a similar band on default habits. Pergolas pay back as pergolas first: judge the £2,500–£4,000 solar margin, which returns in 8–12 years while the structure shades the patio either way. None of these numbers require optimism — they require sunshine your garden either has or lacks, which is why our first advice is always the shade-watch described in the shade article.

One warning common to every route: quotes that bundle "free" extras — bird-proofing, monitoring apps, optimisers — into an inflated headline price. Insist on a line-itemised quote and compare per-kWp. If you would like a second opinion on a quote you have received, send it through the contact form; that costs nothing and regularly saves four figures. Planning costs and the consent route are covered on the planning page, and the FAQs handle the money questions we hear most.