Commercial solar - your questions answered

For most UK businesses with a suitable roof and meaningful daytime electricity usage, yes. Commercial solar typically pays back in roughly 4–7 years, then delivers 20+ years of low-cost electricity. Worth depends on tariff, usage profile, roof condition and finance structure - the calculator gives an indicative view.

• Are commercial solar panels worth it?
• Try the calculator

Commercial sites tend to get stronger returns than domestic because they consume more electricity during daylight hours, when solar generates. High daytime self-consumption is the single biggest driver of ROI.

• Read the worth-it guide
• ROI and payback explained

Typical UK commercial solar delivers an IRR of around 12–20% over 25 years, with simple payback in 4–7 years on a cash purchase. Returns improve with higher electricity tariffs and high daytime self-consumption.

• ROI and payback guide
• Is it worth it?

Savings depend on roof size, energy usage profile, electricity tariffs and finance structure. Many sites cut grid electricity costs by 40–70%. The free calculator gives an indicative figure; a full proposal refines it.

• How solar cuts energy bills
• Try the calculator

On suitable sites with the right usage profile and funding structure, yes - particularly with asset finance or a PPA where monthly repayments come in below the energy savings. Depends on site suitability and finance approval.

• Finance options

As a rough guide, UK commercial solar installations land around £700–£1,100 per kWp installed, so a 250 kWp system is typically £180k–£280k. Cost varies with roof type, access, electrical works, DNO requirements and whether storage is included. A site-specific proposal gives the firm figure.

• Commercial solar costs in detail
• Is it worth it for your site?

Pricing is driven by system size (kWp), roof complexity, cabling distance to the main board, scaffolding and grid connection work. Use the calculator for an indicative cost or request a feasibility review for a firm number.

• Cost guide
• Weighing up the return

There's no nationwide grant that pays for commercial solar outright - the Feed-in Tariff closed in 2019. UK businesses typically fund solar through the 100% Annual Investment Allowance, asset finance, a PPA, or sometimes regional schemes like Scotland's SME Loan + Cashback or the Industrial Energy Transformation Fund. See our solar panel grants & funding guide for the full breakdown.

• Is commercial solar worth it?
• Grants & funding guide

There are three main routes: outright purchase (fastest ROI, full ownership, plus 100% AIA tax relief), asset finance / lease (spread cost over 5–10 years, often cashflow-positive from year one), or a Power Purchase Agreement (PPA - no upfront cost, you buy the electricity generated at a fixed discounted rate). See the finance and grants & funding pages for side-by-side comparisons.

• Finance options
• How PPAs work
• Is it worth it?

Not necessarily. Asset finance, PPAs and lease structures can spread or remove upfront cost, subject to lender approval.

• Is commercial solar worth it?
• Finance options
• PPA guide

Modern commercial mono-PERC and TOPCon panels are around 21–23% efficient. In UK conditions a well-designed system generates roughly 850–1,000 kWh per kWp installed per year.

A single 450–550W commercial panel typically produces around 400–550 kWh per year in the UK. A 250 kWp rooftop system (around 500 panels) generates roughly 220,000–250,000 kWh per year.

Standard commercial panels are roughly 2.3m × 1.1m and 450–600W. A 100 kWp system needs around 180–220 panels and 400–600 m² of usable roof area.

Most large commercial roofs are suitable. Key factors: structural capacity, roof age and condition, orientation, shading, and access. Flat, south-facing or east–west pitched roofs in good condition under 20 years old are usually strong candidates. We confirm headline suitability at the finance review using bills, postcode and roof information, then a desktop survey followed by a full site survey verifies it once the funding route is agreed.

• Roof and structural surveys

From signed proposal to commissioning typically takes 8–16 weeks. Our process runs calculator → qualifying call → finance review → desktop survey → site survey → design & proposal → contract → installation, so the funding route is locked in before any survey effort. The install on the roof itself is usually 2–6 weeks depending on size; DNO approval and grid connection often drive the overall timeline.

• Is commercial solar worth it?
• Our process

In most cases, yes - surplus export is paid for under an export tariff (SEG or commercial PPA). Export capacity is subject to your DNO connection conditions.

• Is commercial solar worth it?
• Smart Export Guarantee for business

Many commercial solar installations fall under permitted development, but planning may be required depending on location, listing status and scale. We review this case by case.

• Is commercial solar worth it?
• Planning permission guide

A formal application to your Distribution Network Operator to connect the system to the grid and confirm export limits.

• Is commercial solar worth it?
• DNO and G99 connections

G99 is the engineering standard governing how generation systems above small thresholds connect to the UK distribution network.

• Is commercial solar worth it?
• DNO and G99 connections

An export limit caps how much electricity you may send back to the grid - sometimes to zero on a constrained part of the network. It does not stop the project. The system is simply designed around self-consumption instead of export: size the array to your daytime base load, fit an export limitation device so the inverters ramp down rather than breach the limit, and consider storage or load shifting to soak up the summer midday surplus. Because on-site electricity is worth far more than export payments, most commercial business cases barely move when export is restricted; the figure to check in your proposal is how much generation is expected to be curtailed and in which months.

• Is commercial solar worth it?
• DNO and G99 connections
• Battery storage guide

Often yes, and it is a common starting point. You need the landlord's written consent - usually a licence for alterations plus a roof licence or lease variation - and the lease needs enough term left to see the payback through; under five years rarely stacks up for a tenant-funded system. From there the usual routes are: you fund and own it and agree removal or handover at lease end; the landlord funds it and recovers the cost through rent or a service charge; or a PPA where a third party owns the kit and you buy the electricity. The points to settle early are who owns the system, who keeps the savings and export income, who insures and maintains it, and what happens at the end of the term. We can help frame the conversation with your landlord.

• Is commercial solar worth it?
• Solar for commercial landlords
• PPA guide

For most sites the answer is very little. The bulk of the work happens on the roof, away from your operations, and is sequenced with your team: delivery and scaffold or mast access at agreed times, roof-side works during normal hours, and loading-bay or yard space booked in advance. The one moment that touches the building is the electrical tie-in and commissioning, which needs a short planned shutdown of the board being connected - typically a few hours, and normally scheduled for an evening, weekend or shutdown week. Warehouses and distribution sites usually continue trading throughout; only work directly beneath an active roof area needs temporary exclusion zones under the CDM plan.

• Is commercial solar worth it?
• Our process
• Safety on commercial installs

Options depend on ownership and finance structure. Some systems can transfer or be repurchased; we explore the right path during proposal.

• Is commercial solar worth it?
• Leased and let buildings

Not always. Batteries can improve self-consumption and resilience but add cost. Many businesses install solar first and add storage later.

• Is commercial solar worth it?
• Battery storage guide

Typically: recent energy bills, postcode, roof information (or photos / drawings), ownership status and an idea of your funding preference. We use this at the finance review - which happens before any desktop or site survey - to confirm the funding route and lock in the system size brief before the design team starts work.

• Is commercial solar worth it?
• Request a feasibility review

Tier-1 commercial panels carry 25–30 year performance warranties and typically still produce 85–90% of original output after 25 years. Inverters are usually replaced once during the system's life (around year 10–15).

• Panel lifespan guide
• Warranties and cover

Panel performance and product warranties (typically 25–30 years), inverter warranties (10–12 years) and installer workmanship warranties - confirmed in your proposal.

• Warranty cover at a glance
• Warranties explained

An owned system can support value in two ways: it lowers the building's running costs, and it usually improves the EPC rating, which matters for MEES lettability and for tenants screening on energy performance. Valuers treat it as one factor among many rather than a fixed uplift, so the honest position is that solar strengthens the letting and resale case - particularly on older stock near an EPC band threshold - without guaranteeing a set increase. Where the system sits under a PPA or lease, the benefit follows whoever holds the contract, so check that before assuming it transfers with the building.

• MEES and EPC compliance
• Solar for commercial landlords

In most cases a UK business can offset a large part of the cost against taxable profits, but which allowance applies depends on how the asset is classified and how you fund it. Solar PV is generally treated as a special rate asset, so the common routes are Full Expensing or the Annual Investment Allowance for companies buying outright, or the 50% First-Year Allowance where those do not apply. Hire purchase usually still qualifies; an operating lease or PPA does not, because you do not own the asset - the funder claims instead, which is normally reflected in the rate you pay. Relief reduces tax, it does not reduce the invoice, and the timing follows your accounting period. Always confirm the position with your accountant before relying on it in a business case.

• Capital allowances guide
• Business rates and solar

Yes. Commercial installations are charged at the standard 20% rate - the zero rate that applies to some domestic work does not extend to business premises. If you are VAT-registered and the system serves taxable business activity, the VAT is normally recoverable as input tax, so it is a cashflow item rather than a real cost. Partly exempt organisations, charities and some public bodies may only recover a proportion, which is worth checking before you budget. Note that finance and PPA payments have their own VAT treatment, so compare quotes on a consistent basis - and confirm your own recovery position with your accountant.

• Finance options
• Capital allowances guide

Usually yes. On-site generation reduces the building's modelled energy use, which is what an EPC assessment measures, so solar often moves a commercial property up a band - most valuably where a building sits just below the MEES minimum of E and cannot currently be let or renewed. The size of the improvement depends on the building, not just the array: a large system on a small, poorly insulated unit shifts the rating more than a modest array on an already efficient one. Two practical points. The EPC must be reassessed after commissioning for the improvement to count, and the modelling gives credit for generation serving the assessed building, so metering and ownership need to be documented. If lettability is your driver, get the current EPC recommendations report reviewed alongside the solar design rather than treating them separately.

• MEES and EPC compliance guide
• Solar for commercial landlords

Commercial solar means solar PV systems installed on business premises - warehouses, factories, supermarkets, offices and industrial sites - to generate on-site electricity, reduce grid demand and cut energy bills. Systems are typically 30 kWp to several MWp and sized around the building's daytime energy usage.

Commercial solar PV (photovoltaic) is the technology that converts daylight into electricity using rooftop or ground-mounted panels wired through inverters into the building's distribution board. It powers on-site loads first, with any surplus exported to the grid.

Panels generate DC electricity from daylight, an inverter converts it to AC, and it flows into your building's supply - offsetting imported grid electricity in real time. Anything you don't use is exported to the grid under an export tariff. A meter records generation, consumption and export.

• How it works, step by step