10kW commercial solar — cost, ROI & payback

At the small-commercial end, installed prices in 2026 sit at roughly £900–£1,100 per kWp ex-VAT, so a 10kW system lands around £9,000–£11,000 ex-VAT, with about £10,500 a fair mid-point for a straightforward pitched or flat roof.⁵ Cost per kWp falls as systems get larger — a 250kW project can reach £650–£750 per kWp — which is why small systems carry the highest unit price. The breakdown below is illustrative for a typical site.

UK commercial roofs yield about 950 kWh per kWp each year, so a 10kW array produces close to 9,500 kWh annually — more in summer, less in winter, and best where the roof is unshaded and reasonably oriented.⁴ The value comes mainly from self-consumption: every kWh you use on site avoids buying grid electricity at the full commercial rate, which is far more valuable than exporting it.

Commercial self-consumption typically runs 60–85% depending on your operating pattern; a business open through daylight hours often sits near the middle. We model 70% here, with the balance exported.

• Self-consumed: ~6,650 kWh, offsetting grid purchases.
• Exported: ~2,850 kWh, paid under a Smart Export Guarantee tariff.³

We value self-consumed units at about 26p per kWh, a typical 2026 commercial electricity rate (business rates broadly sit in the 22–30p band; check your own contract),² and exported units at a mid-range Smart Export Guarantee rate of about 6p per kWh.³

A higher electricity rate, higher self-consumption or a rising tariff shortens payback; a shaded roof or low daytime use lengthens it. All figures are estimates for a typical site and depend on your load, roof and tariff.

Two points are widely misreported, so read them carefully.

VAT: the 0% VAT rate applies to domestic solar only. Commercial solar pays 20% VAT — on a £10,500 system that is £2,100, taking the gross figure to about £12,600. A VAT-registered business normally reclaims this through its VAT return, so it is a cash-flow item rather than a permanent cost. Confirm your position with your accountant.

Capital allowances: solar PV is special-rate plant. That means it qualifies for the 50% first-year allowance — you deduct 50% of the cost in year one, with the remaining balance written down at 6% a year in the special-rate pool. It does not qualify for 100% full expensing, which applies only to main-rate assets.¹

Solar panels are typically warranted for performance over 25 years, degrading slowly at roughly half a percent a year. Holding the annual benefit near £1,900 and allowing for that gentle decline, a 10kW system produces a cumulative benefit in the region of £38,000–£42,000 over 25 years — after allowing for a likely inverter replacement (about £1,500) and light maintenance.

• Net installed cost: ~£10,500 ex-VAT.
• Estimated 25-year net benefit: ~£40,000.
• Return on the net cost: in the order of 3–4x over the system life.

This is an estimate for a typical site and assumes broadly flat real electricity prices. If commercial rates rise — as they have relative to pre-2022 levels⁶ — the return improves, because every self-consumed unit is worth more. Your figures depend on your load, roof and tariff.

A 10kW array is the entry point for commercial solar. It fits businesses with modest daytime demand and a compact roof, rather than energy-intensive sites.

• Roof: around 70 m² of clear, sound roof — a small industrial unit, shop, office, café, surgery, village hall, or a farm outbuilding.
• Electricity bill: roughly £3,000–£6,000 a year. If your bill is much larger, a 20kW, 30kW or 50kW system will usually deliver more value per pound.
• Usage pattern: best where activity runs through daylight hours so most generation is used on site.

If your demand is higher, compare the larger sizes: 20kW, 30kW, 50kW, 100kW and 250kW. For sector-specific numbers see our guides for a warehouse, factory, farm, school, retail unit or hotel.

PlutoHome is a neutral introducer. We are not the installer and do not install, finance or own systems — we match your business with one MCS-certified commercial installer suited to your roof and load, so you get a firm quote rather than a barrage of sales calls.

1. Decide whether you want to own the system outright or explore a funded route — see buy vs PPA.
2. Understand what separates a good installer from a poor one with how to choose an installer.
3. Read the wider picture on the commercial solar hub.

When you are ready for a site-specific figure, request a quote and we will introduce one certified installer to survey your roof and confirm the numbers for your load, roof and tariff.