The Minimum Energy Efficiency Standards (MEES) currently require commercial properties in England and Wales to hold an EPC rating of E or higher to be let on a new or existing tenancy. That has been the law since 1 April 2023. Properties below E are unlettable unless a valid exemption is registered.
The trajectory beyond that has been settled in principle but not in date. The 2021 government consultation proposed EPC C as an interim step (originally 2027, more recently floated as 2028) and EPC B as the final standard from 2030. The government's formal response to that consultation has still not been published.
CBRE's reading of DESNZ signals is that the EPC B requirement will remain but the deadline may slip to somewhere between 2030 and 2035. The direction is clear. The exact date is not.
Three reasons.
First, retrofit projects on commercial buildings routinely take 12 to 18 months from assessment to completion. A building that needs to hit EPC B by 2030 needs serious work commissioned by mid-2028 at the latest. Buildings starting from EPC D or E need to start now.
Second, lender behaviour is already moving. Major commercial property lenders are pricing EPC ratings into refinancing terms today, regardless of the official MEES deadline. A building rated D might still be lettable, but the cost of capital against it is rising.
Third, the supply chain is finite. The same MCS-certified installer base that handles commercial retrofit also handles residential, new build solar under the incoming Future Homes Standard, and council-led portfolios. Lead times will lengthen as 2030 approaches, and the cost of being late will compound.
For commercial property owners, the EPC question has three commercial consequences, each independent of the others.
Lettability. From the deadline date, a non-compliant property cannot be let on a new tenancy and existing leases cannot be renewed. Income stops. The building still carries operational and financing costs.
Refinancing. Commercial lenders are increasingly treating EPC exposure as a credit risk. A B-rated building gets more competitive terms. A D-rated building either gets repriced or restricted on loan-to-value.
Sale value. Buyers price in the cost of compliance work. A non-compliant building sells at a discount roughly equal to the cost of getting it to standard, plus a risk premium for execution. CBRE estimates that 58% of office stock in Central London currently sits below EPC B, which means a substantial proportion of the market is already exposed.
These risks compound. An asset that becomes harder to let also becomes harder to refinance, which makes it harder to hold, which forces a sale into a market that prices it lower. Solar does not solve all of this on its own, but it materially changes the conversation on each.
A commercial EPC is calculated using the Simplified Building Energy Model (SBEM). The two figures that matter are the Building Emission Rate (BER), measured in kgCO2 per square metre per year, and the Energy Use per Floor Area.
On-site solar PV reduces both. Solar generates electricity at the building, which displaces grid imports in the calculation. The carbon factor of grid electricity is built into the model, so every kWh of solar generated is a measurable reduction in BER.
For most commercial buildings, a well-specified solar installation moves the rating one to three bands. The exact uplift depends on system size relative to floor area, the building's existing energy consumption profile, and the technology specification. A typical move would be EPC E to C, or D to B, in a single intervention.
For older or thermally inefficient buildings (very old industrial units, listed buildings, single-glazed offices), solar alone is rarely enough. It needs to be paired with fabric upgrades, LED lighting, or HVAC efficiency measures. But for the majority of commercial buildings, solar is the strongest single intervention measured in EPC bands per pound spent. The technical detail of how solar interacts with SBEM is covered in an earlier blog on improving EPC ratings with solar.
On 15 June 2025, the government overhauled the EPC methodology for existing buildings, replacing the older RdSAP model with a methodology that better reflects on-site generation, battery storage, and modern heat technologies.
A further reform is now in progress. The Department for Energy Security and Net Zero published its partial response to the Energy Performance of Buildings consultation on 21 January 2026, confirming that four new headline metrics will sit alongside the carbon rating: energy costs, fabric performance, smart readiness, and heating system efficiency. The new metrics are expected to be introduced in the second half of 2026.
For commercial property, the practical effect is that solar PV (and battery storage, and EV charging, and heat pumps) all score more strongly under the new methodology than they did under the old one. Solar that might have moved a building from D to C under the old rules is now more likely to push it to B.
Two things follow. The case for solar as a compliance tool is stronger than it was twelve months ago. And properties that were assessed before the methodology change may be carrying an EPC that understates their actual energy performance, which is worth checking before any lease event, refinance, or sale.
The practical implications:
- If you do not know your portfolio's current EPC distribution, find out. Buildings rated D or lower should be flagged as priority.
- Properties with leases expiring before 2030 should have their compliance pathway worked out at the asset level, not deferred to the lease event.
- Solar PV should be the first compliance intervention modelled, because it generates a positive financial return alongside compliance value. Other interventions (fabric, HVAC, lighting) typically have compliance value only.
Procurement should start sooner rather than later. The 2030 deadline (or 2032, or 2035) is not the relevant date. The relevant date is when your supply chain capacity becomes constrained and your finance terms get repriced. Both are already moving.
The MEES trajectory toward EPC B is not in serious doubt, even if the timing is. For commercial property owners, the practical question is no longer "can solar reduce my electricity bill?" but "will my building still be let, refinanced, or sold in five years on terms I can live with?" Solar is one of the few interventions that addresses all three.
Spirit Energy has been designing and installing commercial solar across the UK since 2010, with over 6,000 installations completed across warehouses, hotels, care homes, and other commercial sectors. We can model the EPC impact of a system on your specific building before you commit to anything. Call us on 0118 951 4490 or use the request a quote on our website.