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Typical 2026 Costs by System Size
| System | Suits | Indicative installed cost | Per kWp |
|---|---|---|---|
| 30kWp | Small industrial unit, office | £27,000 to £36,000 | £900 to £1,200 |
| 100kWp | Mid size warehouse, factory | £80,000 to £100,000 | £800 to £1,000 |
| 250kWp | Large warehouse, logistics roof | £175,000 to £225,000 | £700 to £900 |
Ranges are market rates subject to survey, and the survey is what turns them into a fixed figure. Panels themselves are the cheap part now; design, electrical work, access and scaffolding carry the balance.
What Moves the Price
Roof type first. A modern steel portal frame roof takes panels quickly; a fragile or heavily serviced roof needs more engineering. Access and scaffolding costs scale with height and site constraints. The electrical connection matters too, larger systems can involve the network operator, which we manage as part of the project.
Then the quiet cost saver: doing it once. Sizing the inverters and cabling for a future battery, or a second phase of panels, costs little during the first install and avoids repeating the expensive parts later.
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The Net Cost Is Lower Than the Quote
Two reliefs work on the headline number. Capital allowances let most businesses claim substantial first year tax relief on the investment, through the Annual Investment Allowance up to £1m or the 50 percent first year allowance. And the electricity the roof generates starts offsetting your bill from the day the system energises, at commercial rates that make the effective payback three to six years on most sites we model.
The quote we produce shows all three lines: gross cost, tax relief, and year one generation value, so your accountant and your board see the same picture.
