Short answer: Most commercial rooftop systems we install fall in these ranges, excluding VAT: about £17,000–£21,000 for 30 kWp, £28,000–£37,000 for 50 kWp, and £50,000–£65,000 for 100 kWp. Larger systems of 150 kWp and up usually cost £420–£650 per kWp. Where your job lands in the range depends on your roof, your electrical supply and access, not just the panels.
Key facts
- Prices above exclude VAT, which is 20% for businesses. Most VAT-registered businesses can reclaim it.
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Bigger systems cost less per kWp, because fixed costs like scaffolding, design and grid paperwork are spread further.
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A battery adds roughly £350–£450 per kWh installed, including a hybrid inverter.
- In England, eligible rooftop solar is exempt from business rates until 31 March 2035, and the Annual Investment Allowance can cover up to £1m of qualifying spend.
Typical commercial solar prices in 2026
| System size | Typical use | Typical installed cost (ex VAT) |
|---|---|---|
| 30 kWp | Small workshop, garage, office | £17,000–£21,000 |
| 50 kWp | Mid-size unit, farm building, care home | £28,000–£37,000 |
| 100 kWp | Warehouse, factory, large barn | £50,000–£65,000 |
| 150 kWp + | Large industrial roofs, multi-building sites | £420–£650 per kWp |
These are the bands we quote from on our commercial solar page. They’re a guide, not a quote. Every system is designed for the building, so the only way to get a firm price is a survey.
What pushes the price up or down
1. The roof and how the panels are mounted
The roof matters more than anything else. A modern trapezoidal steel roof with good purlins is quick to fix to. Other roofs take more work:
- Flat or membrane roofs usually need a ballasted system, sized to the wind on your site and to what the roof can carry. See our guide to ballasted flat-roof solar.
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Fibre-cement roofs need care. Older sheets may contain asbestos, and we don’t fix panels straight onto asbestos. If the roof is near the end of its life, it can make sense to replace it at the same time. On one Yorkshire farm, we fitted a new trapezoidal roof, solar panels and a battery as one job. See Little Habton.
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Pitched slate or tile roofs on offices can take in-roof systems, which cost more than rail but sit flush.
2. Access and safety
Scaffolding, edge protection, rooflight protection and lifting kit are a real part of the cost, especially on tall or busy sites. On a live industrial site, you also need inductions, RAMS and permit-based electrical isolation, as we did at Woodsmith Mine. Some sites add a permanent fall-arrest lifeline so the array can be serviced safely later.
3. Your electrical supply and the grid
Most commercial systems need a three-phase supply. Systems above the G98 limit need G99 approval from your network operator, which typically adds 8–12 weeks to the programme. Sometimes the network operator asks for export limits or network works, which can change the design or the cost. Read more about G99 applications.
4. The number of buildings and meters
One big roof on one meter is the cheapest setup. Several units, each with its own supply, means more inverters, more metering and more grid applications. At an industrial estate in Oldham, each of the seven units has its own system, inverter and meter, with seven G99 connections.
5. Kit choices
Panel wattage, inverter brand, optimisers on shaded strings, and monitoring all move the price a little. Batteries move it a lot, so we only recommend one when your usage justifies it. See is battery storage worth it for business.
How businesses pay for it
- Buy outright. This gives you the best long-term return. Plant and machinery tax reliefs can reduce the net cost. See capital allowances.
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Finance. Monthly repayments that the savings can help cover. See solar finance.
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A Power Purchase Agreement. A funder pays for the system and you buy the power at an agreed rate. See PPA or buy?.
- Grants, when they’re open. See solar panel grants for businesses.
In practice: what payback looks like on real jobs
Two examples from our case studies, both estimates made at design or handover, not metered results:
- DW Autos, Withernsea: a 17.63 kWp system on a garage’s pitched metal roof, expected to generate 14,885 kWh a year. Estimated payback is about 4 years 3 months.
- Western Waste, Penzance: a 71.875 kWp system with 46.4 kWh of battery storage, on a fibre-cement roof. Handover estimate is 73,803 kWh a year, with estimated payback of about 4 years 1 month.
Payback depends on what you pay for electricity and how much of the solar you use during the day. A site that runs all day, five or six days a week, will usually beat one that’s empty by 3pm.
Things that don’t belong in a quote
Watch out for quotes that skip a survey, leave out scaffolding or the grid application, or don’t say who handles G99. Ask what the workmanship warranty covers. Ours is 24 months on commercial installs, alongside the manufacturers’ product warranties. Also ask whether the installer is MCS certified. We are (NIC-601602).
Frequently asked questions
How much does a 50 kW solar system cost in the UK? For a commercial rooftop, typically £28,000–£37,000 excluding VAT. The roof type, access and grid requirements decide where you land in that range.
How much does a 100 kW commercial solar system cost? Typically £50,000–£65,000 excluding VAT for a rooftop system. Larger systems usually cost less per kWp.
Do businesses pay VAT on solar panels? Yes, at 20%. VAT-registered businesses can usually reclaim it. Some charity buildings currently qualify for 0% VAT until 31 March 2027.
Is a battery included in those prices? No. Batteries are extra, at roughly £350–£450 per kWh installed including a hybrid inverter. We only recommend one when your usage pattern supports it.
Get a firm price
Send us a recent electricity bill or half-hourly data, and the address of the building. We’ll do a desktop design and give you an honest idea of cost and payback before anyone climbs a ladder.
Book a free survey · Call 01482 765063
Related guides: Solar PPA or buy outright? · Warehouse roof solar checks · Business rates and solar panels
