How much do solar panels for businesses cost?

A complete commercial solar PV install for a UK business in 2026 typically costs £20,000 to £270,000 before tax relief, depending on system size and sub-vertical. The headline number on its own is misleading — what matters for an SME is cost per kW (which drops sharply with scale), the financing route, and how 100% Annual Investment Allowance flows through to net effective cost. This page lays out the actual numbers we quote — including ranges by sub-vertical, financing comparisons, and the hidden cost line items that lazy proposals leave out.

Cost per kW by system size

Three pricing bands reflect the underlying economics of commercial PV. Below 100 kW, a single G98 grid-connection application keeps timescales and red tape manageable but per-kW cost is highest because mobilisation, scaffolding, design, and DNO work amortise across fewer panels. Between 100 kW and 500 kW you cross into G99 territory (slower DNO process), but per-kW cost falls thanks to scale on procurement and labour. Above 500 kW the largest commercial sites achieve the best per-kW rate, but design and grid work get more involved. Indicative 2026 UK rates:

• Sub-100 kW: £900–£1,200 per kW. Typical install: a 50 kW office or small retail unit at £45,000–£60,000 turnkey.
• 100–500 kW: £750–£950 per kW. Typical install: a 250 kW light industrial unit at £190,000–£240,000.
• Above 500 kW: £700–£850 per kW. Typical install: a 750 kW logistics warehouse at £530,000–£640,000.

What drives variation in your specific quote

Two installs of identical kW size can vary 25–40% in price based on site conditions. The biggest swing factors: roof condition (an asbestos-cement roof needs replacement first, often combined with the install — adds £40–£100 per square metre), electrical infrastructure (single-phase vs three-phase, switchgear capacity, distance from PV array to point of connection), structural loading (older steel-portal sheds may need additional purlin support), grid connection (G98 simple, G99 with constrained network can require expensive reinforcement), and access (city-centre rooftops with no crane access add scaffolding cost). Our fixed-price quotes lock all of this in — no surprises on day one of the install.

Financing — cash, asset finance, or PPA

For a UK limited company, cash purchase combined with 100% Annual Investment Allowance gives the strongest IRR and shortest payback — typically 5–8 years for SME installs. The AIA effectively returns 25% of capex as tax relief in year one for a profitable company at current corporation tax rates, so an £80,000 install costs £60,000 net. Asset finance over 5–7 years is the route most of our SME customers choose: the monthly finance payment is consistently lower than the monthly bill saving, so the install is cash-flow positive from month one with no capex outlay. After the finance term you own the system outright and continue saving for another 18–20+ years. PPA (power purchase agreement) is zero-capex — a third party owns the system and sells you the generated power at a discount to grid retail. PPAs make sense for businesses without the corporation tax position to absorb AIA, businesses constrained on capex, or businesses planning to relocate within 5 years.

Payback method — what the numbers actually mean

"Payback" gets used loosely. We always model four numbers so you can compare proposals like-for-like: simple payback (years until cumulative savings equal capex), discounted payback (same but with cost of capital factored in), IRR (internal rate of return over 25 years), and NPV (net present value at your chosen discount rate). For most UK SMEs in 2026, simple payback runs 5.8–7.5 years, IRR 11–18%, and 25-year NPV £150k–£900k depending on system size. We share the full PVSyst yield model and DCF spreadsheet — your accountant gets clean numbers, not a marketing brochure.

Hidden costs proposals often miss

Watch for these line items. DNO connection: G98 application is typically £350–£500, G99 can range from £1,500 to £30,000+ depending on network reinforcement requirements. Structural survey: £600–£1,500 if your building drawings aren't current. Roof remediation: any leaks or membrane damage discovered during install must be fixed before panels go on — budget £500–£5,000 contingency. Scaffolding: £2,000–£15,000 depending on building height and access. Asbestos survey: pre-2000 buildings need an Asbestos Management Survey before any roof work — £400–£900. Cabling and switchgear upgrade: a small office with a 60A single-phase supply may need a three-phase upgrade for any system above ~17 kW per phase — £3,000–£15,000. We itemise all of this on every quote so you can compare honestly with cheaper proposals that bundle hidden contingencies into change orders.

Install timeline and cash flow profile

Contract to commissioning typically runs 8–16 weeks for sub-100 kW SME installs and 6–12 months for 100–500 kW projects (mostly waiting on G99 DNO). Physical install on site is fast — 1–4 weeks depending on size. The cash flow profile if self-funded: deposit 20% on contract, 60% on delivery to site, 20% on commissioning. If asset financed, no capex from you; the finance company pays us in stages, and your monthly debit starts the month after commissioning. Generation begins at commissioning and savings flow from month one.