Commercial MEES planning has been unsettled for years, and much of the advice still circulating online is out of date. Following the Government's June 2026 interim response, the position has two distinct parts and it is essential not to blur them.
**Current law:** the minimum standard for letting most non-domestic property in England and Wales remains EPC E, subject to applicable exemptions. It is unlawful to let most commercial buildings rated F or G.
**Intended future requirement:** the Government intends to introduce a minimum EPC B requirement from 2031 for privately rented non-domestic buildings over 1,000 m², where cost-effective and subject to the necessary legislation. The previously proposed EPC C milestone for 2027 has been dropped.
EPC B in 2031 is not yet the law. It is a stated policy intention that requires secondary legislation to take effect. Treating it as settled is as unhelpful as ignoring it.
What changed, and why it matters commercially
The trajectory most portfolios were planning against — EPC C by 2027, EPC B by 2030 — no longer reflects Government policy. Dropping the 2027 milestone removes a near-term cliff edge that was driving rushed, low-value interventions on buildings due for refurbishment anyway.
In exchange, the intended endpoint is more demanding and more targeted. EPC B is a materially harder standard than EPC C, and the 1,000 m² threshold concentrates the obligation on larger assets where the capital works are more significant.
The commercial consequence is a change in tempo, not direction. There is more time, and the destination is further away. Buildings below 1,000 m² are currently expected to remain subject to the existing EPC E minimum.
Do not mistake more time for less risk
A 2031 horizon sounds comfortable until you map it against lease events. Getting a large office or industrial asset from D or C to B is rarely a single project. It usually involves fabric measures, plant replacement, lighting and controls, and often on-site generation — works that are far cheaper when they coincide with a void, a refurbishment or an end-of-life plant replacement.
Count the lease events between now and 2031 for your larger assets. For many portfolios the answer is one, sometimes two. If you miss them, you are looking at works in occupation, with the disruption, tenant negotiation and cost premium that implies.
Lenders and investors are also not waiting for the legislation. Energy performance is already priced into due diligence, and an asset with no credible path to B is already harder to finance and to sell.
The 'where cost-effective' qualifier
The intended requirement is framed as applying where cost-effective, and existing cost-effectiveness and exemption mechanisms are intended to continue. That is a genuine protection for buildings where improvement is not viable.
It is not, however, a plan. Registering an exemption requires evidence, and evidence requires assessment. An assumed exemption with no supporting analysis is not a defence, and it leaves the asset carrying full regulatory risk with none of the mitigation.
Where an asset genuinely cannot reach the standard cost-effectively, that conclusion should be documented as deliberately as a retrofit plan would be.
Where the EPC itself is the problem
One point that consistently surprises owners is how often an asset's rating understates its real performance. Standard SBEM modelling applies conservative default assumptions where building data is missing or where the geometry is unusual.
Buildings with atriums, glazed cores, complex shading or unusual servicing strategies are frequently penalised by those defaults. Dynamic Simulation Modelling can represent them accurately, and where the building genuinely performs better than the defaults assume, the resulting rating can improve — sometimes by a band or more — without a single item of physical work.
This is not a loophole and it will not rescue a genuinely poor building. It is simply accurate modelling. We cover it in detail in DSM modelling for atriums and glazed cores.
A practical plan for the next twelve months
1. Build a complete EPC register across every lettable unit, including expiry dates. An expiring certificate is a decision point, not an administrative task.
2. Segment by floor area. Assets over 1,000 m² in the privately rented non-domestic category are the ones the intended 2031 requirement targets.
3. Identify anything currently at F or G. That is a live legal exposure today under the existing EPC E minimum, not a future one.
4. For larger assets, model the cost to reach B and compare it against the planned capex and lease event calendar.
5. Review whether the existing assessment reflects the building accurately, particularly for architecturally complex assets, before committing to physical works.
6. Record exemption positions with evidence rather than assumption.
How we help
Oak Tree Rule works with landlords and asset managers across multi-site portfolios through our commercial EPC service, including DSM where the building warrants it, and our energy audit service where the question is which measures actually pay.
For portfolio-level exposure mapping, see our guidance for multi-site portfolios, or get in touch for a MEES exposure review.
This article reflects the position as at September 2026 and is general guidance, not legal advice. The intended EPC B requirement for 2031 is subject to the necessary legislation and its final scope may differ.
Frequently asked questions
- What is the current minimum EPC rating for letting commercial property?
- EPC E remains the current legal minimum under MEES for most non-domestic lettings in England and Wales, subject to applicable exemptions. It is unlawful to let most commercial buildings rated F or G.
- Is EPC B by 2031 now law?
- No. It is the Government's stated intention following the June 2026 interim response, applying to privately rented non-domestic buildings over 1,000 m², where cost-effective. It requires the necessary secondary legislation to take effect.
- What happened to the EPC C requirement for 2027?
- The previously proposed EPC C milestone for 2027 has been dropped. Advice referring to EPC C by 2027 or EPC B by 2030 no longer reflects Government policy.
- Do buildings under 1,000 m² have to reach EPC B?
- Buildings below the 1,000 m² threshold are currently expected to remain subject to the existing EPC E minimum, rather than the intended 2031 EPC B requirement.
- Can better EPC modelling improve a rating without physical works?
- Sometimes. Where standard SBEM defaults understate a building's real performance — common with atriums, glazed cores and complex geometry — accurate Dynamic Simulation Modelling can produce a more representative rating. It must reflect genuine building performance, not optimistic assumptions.