Is Commercial Solar Worth It in 2026? The Honest Numbers

The short answer, and the honest caveat

For most UK businesses that use a lot of electricity during daylight hours, commercial solar is worth it. A well-sized rooftop system commonly pays back in 4 to 7 years and then produces low-cost power for a further 15 years or more, with panels warrantied for around 25 years.

That is the headline. The honest caveat is that the economics depend almost entirely on how much of the generated power you use yourself. Solar is not equally worth it for every business, and this guide sets out where it stacks up and where it does not.

The economics come down to self-consumption

The single biggest driver of return is self-consumption: the share of your generation you use on site rather than export.

Every kilowatt-hour you consume yourself displaces grid electricity you would otherwise buy at the full commercial rate. Every kilowatt-hour you export instead earns the Smart Export Guarantee (SEG) rate, which is materially lower than the retail price you pay. The Feed-in Tariff closed to new applicants some years ago; SEG replaced it and pays for exported power, with generators up to 5 MW eligible.

In plain terms, avoided purchase is worth far more than export income. A business that consumes 70 to 80 percent of its generation on site sees a much stronger payback than one exporting half of it. That is why solar suits operations that run through the day: manufacturing, warehousing, cold storage, agriculture, retail, offices and hospitality.

To model your own numbers against your actual tariff and roof, use the finance calculator and read our full payback and ROI breakdown.

The tax and rates position (correct for UK companies)

The tax treatment improves the real return, and getting it right matters.

• Capital allowances. Solar PV is classed as special rate plant and machinery. It does not qualify for 100 percent full expensing (that is main rate only) or the newer 40 percent first-year allowance. It does qualify for the Annual Investment Allowance (AIA), which gives 100 percent first-year relief on up to £1m of qualifying spend. For the great majority of commercial installs, the AIA covers the whole cost. Where spend exceeds the £1m cap, companies can claim the 50 percent special-rate first-year allowance on the excess, with the remaining balance written down at 6 percent a year.
• VAT. Commercial solar is charged at the standard 20 percent VAT rate. The 0 percent domestic rate does not apply to business installations. If you are VAT-registered, that VAT is normally reclaimable.
• Business rates. Rooftop solar used for self-consumption is 100 percent exempt from business rates in England from April 2022 to March 2035, so generating your own power does not increase your rateable value.

These reliefs meaningfully shorten payback, but eligibility depends on your structure and tax position.

This is general information, not tax advice. Confirm your specific position with your accountant.

Comparing the finance routes

Whether solar is “worth it” also depends on how you pay for it. The upfront-cash return is the strongest on paper, but many businesses prefer to keep capital free and let the system fund itself from day one.

Route	Upfront cost	Who owns the asset	Best suited to
Capital purchase	Full cost	You	Cash-rich businesses wanting the highest lifetime return
Hire purchase	Deposit	You (at term end)	Firms wanting ownership plus capital allowances, spread over time
Asset finance	Low or none	You (typically)	Spreading cost while retaining the tax reliefs
Operating lease	None	Funder	Off-balance-sheet treatment and predictable monthly cost
Green loan	None	You	Keeping the asset while borrowing against future savings
Power purchase agreement	None	Funder	Zero-capital sites paying only for the power they use
No upfront cost	None	Varies	Businesses wanting savings without any capital outlay

Funded routes trade some lifetime return for zero or low upfront cost and immediate net savings. Under a PPA you buy the generated power at an agreed rate, usually below grid price, with no capital commitment. Our finance options compared page walks through the trade-offs in detail.

Run the payback logic yourself

A simplified way to sense-check any quote:

1. Take the installed system cost after any VAT reclaim and capital allowance relief.
2. Estimate annual savings: self-consumed units times your electricity price, plus exported units times the SEG rate.
3. Divide net cost by annual savings for a rough payback in years.

If the answer sits inside 4 to 7 years for a self-consumption system, the numbers are broadly in line with a healthy UK install. Rising grid prices shorten payback further, because every self-consumed unit is worth more.

For public sector bodies, note that Salix funding under the Public Sector Decarbonisation Scheme is available to public sector organisations only and does not apply to private businesses. Other support is summarised on our grants and funding page.

When commercial solar is NOT worth it

Solar is a good investment for most, but not all. Be cautious if:

• Your daytime demand is low. A business that draws most of its power at night, or is closed during the week, exports most of its generation at the lower SEG rate. The payback stretches out and the case weakens.
• Your roof is poor. Heavy shading, north-facing pitch, a roof near the end of its life, or a structure that cannot carry the load all cut yield or add cost. A roof survey is essential before committing.
• You are likely to relocate soon. If you rent and may leave within a few years, or expect to sell the premises, you may not be around to capture the payback. Lease terms and landlord consent matter here.
• Your electricity price is already very low. The lower your tariff, the less each self-consumed unit saves, and the longer the payback.

None of these are automatic disqualifiers. A funded route such as a PPA or operating lease can still make sense on a marginal site because you avoid the capital risk. But they are the cases where a proper site-specific quote is most important before you decide.

So, is it worth it for you?

For a business with steady daytime consumption, a sound roof and a plan to stay put, commercial solar in 2026 is one of the more predictable investments available: a defined payback, strong tax reliefs, and a long tail of low-cost power once the system is paid off. For sites with low daytime demand or poor roofs, the case is weaker and worth testing carefully.

The only way to know your real numbers is to price your specific roof, tariff and usage. We are a comparison and quote service, not a lender or financial adviser, and we connect you with vetted MCS-certified installers and funders.

Get costed quotes across every funding route, then compare the payback side by side and decide with real figures rather than averages. You can also review typical installation costs before you start.