Cost
How much do commercial solar panels cost in the UK?
A typical UK SME install ranges from £20,000 (small office, ~25 kW) to £270,000 (light industrial, ~300 kW). Cost per kW is £900-£1,200 below 100 kW, falling to £700-£850/kW above 500 kW. After 100% AIA tax relief, effective net cost for limited companies is roughly 75% of headline price.
A typical UK SME commercial solar install in 2026 lands somewhere between £20,000 and £270,000 turnkey. A small office at around 25 kW costs about £22,000-£28,000. A 100 kW system on a light-industrial unit runs £85,000-£105,000. A 300 kW install on a large warehouse or garden centre lands at roughly £225,000-£270,000. Cost per kW falls steeply with system size: expect £900-£1,200/kW below 100 kW, £750-£950/kW between 100-500 kW, and £700-£850/kW above 500 kW. After 100% Annual Investment Allowance tax relief, the effective net cost for a profitable limited company is roughly 75% of the headline price.
What’s actually included in a commercial solar quote
A fixed-price commercial solar quote should cover everything from feasibility through commissioning. That includes the panels themselves (roughly 30-35% of total cost in 2026), the inverters and optimisers (15-20%), DC and AC cabling, mounting system, isolation switchgear, scaffolding and access, structural roof survey, DNO connection application, MCS commissioning, building control sign-off, and a 10-year insurance-backed workmanship warranty.
What’s often left out of cheap quotes: structural strengthening if your roof needs it, asbestos surveys for pre-2000 buildings, three-phase upgrades, smart export meter installation, and any CDM coordinator costs for installs above 30 person-days. Always ask for a fixed-price turnkey quote rather than a piecemeal one.
Worked example: 100 kW office and warehouse
A 100 kW system on a typical 60-employee office uses around 185 panels covering 600 m² of roof. Headline cost £92,000. Annual generation: about 90,000 kWh. With self-consumption around 65% and a grid price of 38p/kWh, annual savings hit £22,000 (£17,400 displaced grid + £4,725 SEG export at 5p/kWh blended). Simple payback: 4.2 years before tax relief, around 3.1 years after AIA.
The same 100 kW system on a light-industrial unit with daytime weekday operations achieves higher self-consumption (75-80%), pushing payback below 4 years even before tax relief.
What drives the cost up or down
| Factor | Impact on £/kW |
|---|---|
| System size | Larger = cheaper per kW (economies on inverter, scaffolding, DNO) |
| Roof type | Standing-seam metal cheap; pitched tile expensive; flat with ballast mid |
| Three-phase upgrade needed | Adds £2,500-£8,000 |
| Optimisers vs string inverter | Optimisers add £80-£120 per panel |
| Battery storage retrofit-ready | Adds £2,000-£4,000 to switchgear |
| Asbestos roof | Adds £5,000-£20,000 for survey + management |
| G99 application (>100 kW) | Adds 6-18 months and £2,000-£5,000 in fees |
Common misconceptions about commercial solar pricing
The biggest cowboy red flag is a £/kW figure that ignores VAT. Standard 20% VAT applies to commercial solar in the UK — you can’t borrow the zero-rated VAT relief that domestic installs receive. If a quote looks dramatically cheaper than the market, check whether VAT is included.
A second misconception: that price has come down every year. It hasn’t. Module prices have continued to fall, but UK labour, DNO fees, scaffolding hire, and copper cabling have risen sharply since 2023. Net result: total install cost per kW has been roughly flat for three years. If anyone tells you “wait a year and it’ll be 30% cheaper”, they’re wrong.
Next steps
We model every SME quote from your half-hourly meter data and a structural roof survey. Get a free no-obligation feasibility study within 7 working days. For a deeper breakdown of costs, see our commercial solar cost guide or the page on grants and funding routes. Related FAQs: cost per kW, 100 kW system cost, payback period.
Related questions
What does commercial solar cost per kW in the UK?
Commercial solar in the UK costs £900-£1,200 per kW for systems under 100 kW, £750-£950/kW for 100-500 kW systems, and £700-£850/kW above 500 kW. The figure includes panels, inverters, mounting, install, DNO connection, and a 10-year workmanship warranty — but excludes battery storage and any structural or three-phase upgrades.
How much does a 100 kW commercial solar system cost?
A 100 kW commercial solar system in the UK costs £85,000-£110,000 turnkey in 2026, depending on roof type, three-phase status, and whether optimisers are specified. Typical annual generation is 90,000-95,000 kWh, saving £20,000-£25,000/year for a daytime-occupied SME at current grid prices. Simple payback lands at 4-5 years before tax relief, 3-4 years after AIA.
What is the payback period for commercial solar panels?
Commercial solar panels typically pay back in 5-8 years in the UK in 2026, with the median around 6.5 years. Profitable limited companies using 100% AIA tax relief see payback fall to 3-5 years. The asset then continues generating savings for another 17-22 years before requiring inverter replacement, with panels still producing 87% of original output at year 25.