Office Investment Property: Solar for Commercial Property

An office held as an investment asset is the one commercial type where the value case for solar is documented in the rental and capital evidence, not just the energy bill. The problem is structural: the landlord owns the roof and carries the EPC liability, but the occupier pays the electricity under a fully repairing and insuring lease — so the party who funds the panels is rarely the party who consumes the power. We exist to engineer the ownership and lease structure so the right party pays and the right party benefits, and on offices that means tying the array to the asset’s letting strategy, ESG reporting and reversionary value rather than treating it as a plant-room upgrade.

The ownership challenge specific to office investment

On a let office, the occupier typically holds the meter and pays for grid electricity directly. If you, as landlord, fund a rooftop array, you have bought an asset whose output flows straight to the tenant — and unless you have a contractual mechanism, you receive nothing for it. That is the split incentive, and it is the single reason most office solar projects stall. We resolve it through one of the established routes set out in our split-incentive guide: a landlord-to-tenant power purchase agreement (PPA) priced below the grid rate, a roof or airspace lease, a green-lease contribution capped at the tenant’s own savings, or — on a multi-let building — by serving the common parts you already control and pay for.

The common-parts route is usually the cleanest entry point on an office. Lifts, landlord lighting, mechanical ventilation, communal HVAC, the car park and any EV chargers are landlord-supplied and landlord-paid. Solar feeding those loads has no split incentive at all: you fund it, you consume it, you keep the saving. It also improves the building’s EPC ahead of re-letting and trims holding costs during voids. For the larger demawnd — the tenant’s own consumption across let floors — a PPA or a sub-metered green-lease arrangement carries the bulk of the generation. Note that under the RICS Service Charges in Commercial Property professional statement, 2nd edition (in force 31 December 2025), the initial capital cost of new plant such as solar is not recoverable through the service charge; recovery must come through a PPA, a capped green-lease contribution, or rent.

Why office demand suits solar — and where the battery earns its place

Offices run a Monday-to-Friday, daytime load profile that maps closely onto solar generation. Lighting, IT, servers, HVAC and lifts peak through the working day, which is exactly when a roof is producing. That alignment lifts self-consumption — the single biggest driver of return — well above what an intermittent-occupancy building achieves. A daytime-shifted office with no storage typically self-consumes 50–70% of generation; add a battery and that rises to 60–80%, with the store soaking up midday surplus and discharging into the evening shoulder or the Monday-morning ramp.

The economics matter because self-consumed solar displaces grid electricity at roughly 24–28p per kWh (2026 commercial rates, ex VAT and CCL), whereas exported surplus earns a Smart Export Guarantee top-up of around 12–16p. The Smart Export Guarantee is supplier-set, not a government rate, and the best agnostic fixed tariffs sit around 12–15p; treat export as a top-up, not the headline return. A battery’s value on an office is therefore mostly about capturing weekend and midday surplus you would otherwise export cheaply — and on sites with a contracted route to market it can add a grid-services stream, though we never build that into a standard payback.

Sizing and economics for office stock

Office investment assets generally take a 100–500 kW system, depending on roof area, the proportion of single-storey versus multi-storey footprint, and how much of the load you can reach without a private-wire run. At a UK yield of around 950 kWh per kWp per year, that is roughly 95,000 to 460,000 kWh of annual generation.

Indicative capital cost is £700–£1,100 per kWp, falling with scale, and commercial installs have carried 0% VAT since April 2022:

Payback typically lands at 4–8 years, around 6.5 on a representative office, and pulls in to 3–5 years on high-load buildings with strong daytime self-consumption. The Annual Investment Allowance (£1m, permanent) gives 100% first-year tax relief on the special-rate solar asset for a business that buys to use; landlords buying to lease the asset rely instead on the 6% writing-down allowance, so the structure you choose changes the tax position — our capital allowances guide for owners sets this out. See our cost page for the full breakdown.

The green premium — the office-specific value case

Offices carry the strongest published evidence that environmental performance is associated with higher rents and capital values. JLL’s analysis of prime Central London offices (2017–21) found BREEAM-certified buildings associated with rents around 11.6% higher and capital values around 20.6% higher, and put the relationship at roughly +4.2% rent and +3.7% capital value per single EPC band. Knight Frank found rental premia ranging from +3.7% to +12.3% across BREEAM tiers.

Read those figures carefully. They are associations observed in a specific market — prime Central London offices over a specific window — not guarantees, and not a causal claim that solar alone delivers them. We say “associated with”, never “caused by”, and we do not read prime-London numbers across to regional or secondary stock, where the relationship is weaker and the evidence thinner. Solar contributes to the EPC and BREEAM inputs that underpin the premium; it is one lever, not the whole mechanism. Our green-premium guide walks through how the evidence applies — and where it does not.

ESG, Scope 2 and the FTSE-tenant renewal

Where an office houses a listed or institutional occupier, on-site solar becomes a documentation asset. Generation is an on-site Scope 2 abatement that feeds the tenant’s carbon reporting and the landlord’s own GRESB submission (the 2025 cycle covered 2,382 assessments across 1,002 fund managers, watched by 150-plus institutional investors), CRREM stranding pathways, SFDR Article 8/9 classifications and TCFD disclosure. A FTSE tenant coming up to renewal increasingly tests a building against its own net-zero commitments before it re-signs — and a metered, certificated solar array, with the Renewable Energy Guarantees of Origin (REGOs) accounted for, is concrete evidence rather than a marketing line. Our ESG and net-zero funds guide covers how to package this for an investment committee.

MEES: the binding floor and the proposed B

The only binding law today is the Minimum Energy Efficiency Standard floor of EPC E: since 1 April 2023 it has been unlawful to continue letting a commercial property in England and Wales rated below E, including to sitting tenants (gov.uk MEES guidance). Breach penalties run to 10% of rateable value (capped at £50,000) under three months, and 20% (capped at £150,000) at three months or more, plus entry on a public breach register.

Looking ahead, EPC B by 2031 is a proposal, not law — set out in the Government’s interim response of 18 June 2026, applying only to privately-rented non-domestic buildings over 1,000 m², only where cost-effective, and subject to secondary legislation. The earlier “EPC C by 2027” target was scrapped, and “EPC B by 2030” was never law. We flag this because misstating it is common in the market and getting it right is the difference between a sound capex case and a panicked one. Solar typically lifts a commercial EPC by one to three bands — we never promise a specific jump — and on an office sitting at C or D that movement can be the deciding factor in lettability. See our MEES guide for the full timeline.

A realistic worked example (illustrative)

Consider a multi-let office of around 4,500 m² on a business park, held as an investment, currently EPC C, with a 250 kW rooftop array.

• Capital cost: approximately £185,000 (ex VAT)
• Annual generation: around 237,000 kWh
• Self-consumption: roughly 60% across common parts (landlord-supplied) plus a sub-metered landlord-to-tenant PPA on the let floors, with a small battery shifting midday surplus
• Displaced grid value: self-consumed units at ~26p, export top-up at ~13p
• Payback: in the order of 6–7 years before tax reliefs; faster once the Annual Investment Allowance and the rooftop business-rates exemption (100% exempt to 31 March 2035 in England) are applied
• Asset effect: an EPC improvement supporting re-letting, plus ESG documentation for the renewing FTSE tenant

These figures are illustrative and depend on roof orientation, the actual load profile, tariff and the lease structure — every building is modelled individually before we commit a number. Start with a tailored quote.

Common questions

Does solar genuinely raise an office’s value, or is that a sales line?

The honest answer is that the published evidence shows an association, strongest for prime Central London offices, not a guaranteed uplift. JLL’s 2017–21 work links BREEAM certification to around 11.6% higher rents and 20.6% higher capital values, and roughly +3.7% capital value per EPC band — but those are market observations in a specific segment, and solar is one input into the certification, not the sole cause. On regional or secondary office stock the relationship is weaker. We model the value case on what your specific asset and market support, not on headline prime-London figures.

Who pays and who benefits if my office is fully let on an FRI lease?

That is the split incentive, and the answer depends on the route you choose. On common parts you control — lifts, landlord lighting, communal HVAC, the car park — you fund and consume the power directly, so you keep the saving with no contractual complexity. For the tenant’s own consumption you can put a landlord-to-tenant PPA in place (the tenant buys solar electricity below the grid rate, you earn the margin) or a capped green-lease contribution. Our split-incentive guide sets out each structure and its tax and registration consequences.

Will I need planning permission to put solar on a city-centre office?

Often not, but not never. Rooftop commercial solar is permitted development under Class J with a 56-day prior-approval step covering design, appearance and glint or glare (legislation.gov.uk SI 2023/1279 removed the old 1 MW cap in December 2023). The exclusions matter for offices: listed buildings and scheduled monuments are out, a conservation-area or city-centre setting can trigger additional scrutiny, and an Article 4 Direction can withdraw permitted-development rights entirely. Above roughly 50 kW the G99 DNO grid connection is usually the real timing constraint rather than planning. We check all of this at survey before committing to a programme.