solar panels for commercial property in Slough

Serving Slough and the wider Berkshire area, including Windsor, Maidenhead, Langley.

Slough holds more commercial floorspace per head than almost anywhere in the South East, and most of it sits in the hands of landlords and investors rather than the businesses occupying it. That ownership structure is exactly what makes solar an asset decision here, not an energy one. If you own warehousing, light-industrial units, offices or trade counters across SL1 to SL6, the question is no longer whether your buildings perform — it is whether their EPCs let you keep letting them, and whether their capital value moves when the market starts pricing energy performance into yields.

MEES is already biting the Slough stock

Since 1 April 2023 it has been unlawful to let a commercial property in England and Wales with an EPC below E. That is current law, not a future proposal, and it applies on continuing leases — not just at the point of a new letting. A material slice of Slough’s older industrial and office stock was built or last refurbished decades ago, and plenty of it sits at E, F or G. The moment a unit drops below E, it becomes legally unlettable until you either improve it or register a valid exemption. For a landlord that means rent stops, the asset sits empty, and the void shows up directly in valuation.

Looking further out, the government has proposed an EPC B minimum by 2031 for commercial buildings over 1,000 m². That date is not yet law — the earlier C-by-2027 milestone was scrapped and the B target has never been legislated — but it signals direction of travel, and it matters most for the larger sheds and office blocks that define estates like Slough Trading Estate. A 100,000 sq ft logistics unit at EPC D is comfortably lettable today and potentially stranded under a future B regime. Solar is one of the few interventions that moves an EPC meaningfully without gutting the building, because on-site generation reduces the modelled energy demand the certificate is scored against.

Why the green premium is real money in Slough

Slough’s draw has always been logistics geography — the M4, the M25, Heathrow on the doorstep, and now Crossrail through the centre. Occupiers competing for those locations increasingly screen buildings on energy performance because their own corporate carbon reporting depends on it. JLL’s analysis of prime offices found rents associated with a +11.6% uplift and capital values +20.6% for the best-rated stock. Those figures are drawn from prime London and won’t transfer pound-for-pound to a Liverpool Road Industrial Estate unit, but the mechanism is identical: better-rated buildings let faster, hold tenants longer, and command tighter yields. In a heavily-let market like Slough, the cost of a void or a rent-free incentive to fill a poor building usually dwarfs the cost of the solar that would have prevented it.

Slough Borough Council is targeting net zero by 2030 — one of the more aggressive local timelines in the region — which keeps planning policy and occupier expectation pointed the same way. The brand-led redevelopment around the Horlicks Quarter and the continued reletting churn across the trading estate both reward owners who can hand a prospective tenant a B or C certificate rather than apologise for a D.

Ownership routes that solve the split incentive

The standard objection from landlords is the split incentive: under a full-repairing-and-insuring lease the tenant pays the energy bills, so why would an owner fund generation the occupier benefits from? In Slough’s multi-let estates there are four routes that resolve this cleanly.

Common-parts supply. On multi-let estates and managed buildings, the landlord already supplies and recharges shared loads — estate lighting, pumps, lifts, security, EV bays. Solar feeding the common-parts meter cuts a cost the landlord directly carries and recovers through the service charge, with no tenant negotiation required.

Tenant PPA. You fund and own the array, then sell the generated power to the occupier under a power purchase agreement at a rate below the grid. The tenant saves on day one, you earn a contracted return on the roof, and the EPC uplift accrues to your asset. This is the workhorse model for single-let warehouses on the trading estate.

Sell the roof. Lease the roof space to a third-party operator who funds and runs the system. You take a rent and the EPC benefit with no capital outlay — useful where you want the rating improvement but would rather not tie up funds.

Owner-occupier. If you trade from your own building, the split disappears entirely. You self-consume the generation, and self-consumption is the whole return driver — every kWh you use on site displaces a unit you would have bought at full commercial rate.

For landlords holding several units, the right answer is usually a blend across the portfolio, sequenced by lease event and EPC risk. We work through that prioritisation in the split incentive guide and map it against rating risk in the MEES and EPC guide. The portfolio mechanics — funding, metering and rollout across a held estate — are covered for multi-let buildings and commercial property portfolios.

Local cost and grid reality

As a planning figure, commercial rooftop solar runs around £700 to £1,100 per kWp installed, ex-VAT, with the 0% VAT rating applying to qualifying installations. A typical Slough warehouse roof carrying 250 to 500 kWp therefore sits in the low-to-mid six figures, against payback of roughly four to eight years where self-consumption is high — and logistics and trade occupiers with daytime load profiles tend to consume a large share of generation directly, which is what shortens payback. Berkshire’s irradiance supports roughly 950 kWh per kWp per year, so the generation maths is predictable.

Solar capital qualifies for 100% relief under the Annual Investment Allowance up to the £1m cap — note it is special-rate plant, so it does not attract full expensing — and the array is exempt from business rates through to 2035. The real constraint in Slough is not roof space or sun; it is the grid. Any system above roughly 50 kW needs a G99 connection agreement from the local DNO, and on a dense, energy-hungry estate like Slough Trading Estate the local network can be heavily loaded. Connection capacity and timelines vary unit by unit, so the grid position has to be confirmed early — it often dictates how large a system a given roof can actually export or even sanction. Since December 2023 the 1MW permitted-development cap on rooftop solar has been removed (Class J, 56-day prior approval), so planning is rarely the bottleneck; the planning and grid guide walks through the G99 process in detail.

An illustrative Slough portfolio

Take a landlord holding eight units across Slough Trading Estate and Langley Business Park — a mix of mid-box logistics and trade-counter space, roughly half let on FRI terms, two units sitting at EPC E with lease breaks inside three years. Treated as one programme rather than eight one-offs, the play is: solar on the two at-risk units first to lift them clear of MEES before the breaks expose them, common-parts arrays on the managed buildings to cut service-charge energy, and tenant PPAs offered to the daytime-load occupiers at renewal. The estate-wide effect is a portfolio that no longer carries stranding risk, a measurably better EPC profile when units come to market, and a contracted income strip from the PPAs sitting on top of the rent roll. The numbers only work when sequenced against lease events and grid capacity — which is precisely what a feasibility exercise is for.

Start with the numbers for your buildings

Every Slough asset is different — roof condition, occupier load, lease structure and the DNO’s local capacity all move the answer. The sensible first step is a fixed-price feasibility on the specific units that matter to you. See the cost breakdown for how the figures build up, then request a quote and we will model the EPC uplift, self-consumption and payback for your Slough portfolio before you commit a pound.