The Brown Discount: How EPC Ratings Are Affecting Commercial Property Values

What is the brown discount?

The brown discount refers to the reduction in value that energy-inefficient commercial buildings suffer compared to similar buildings with better energy performance. The term draws a contrast with the "green premium", the additional value that highly rated buildings can command. In practice, market evidence suggests the effect operates more as a discount on poor-performing assets than as a premium on good ones. Energy efficiency is becoming the expected baseline, not a bonus feature.

The brown discount manifests in several ways: lower capital values at sale, reduced rental values, longer void periods, higher tenant incentives, and less favourable financing terms. It is not a single number, the magnitude varies by property type, location, and the specific EPC rating, but the direction is consistent across the market.

Evidence of value impact

Quantifying the brown discount precisely is challenging because no two commercial properties are identical, and isolating the EPC effect from other factors (location, specification, lease terms, market conditions) requires careful analysis. However, several sources of evidence point to a measurable impact:

Valuation adjustments: RICS-registered valuers are increasingly factoring energy performance into their valuations. The RICS Valuation Standards (Red Book) require valuers to consider sustainability factors, including EPC ratings, as part of their assessment. Anecdotal reports from major valuation firms suggest that adjustments of 5% to 15% are being applied to properties rated E, F, or G, with the discount increasing for the worst-rated buildings.

Transaction data: Academic and industry research has examined transaction records to identify price differentials between buildings with different EPC ratings. Studies of the UK commercial property market have found that buildings rated F or G transact at discounts of 10% to 20% compared to equivalent buildings rated C or above, after controlling for other property characteristics. Properties rated D or E show smaller but measurable discounts of 5% to 10%.

Institutional investor mandates: Many institutional investors, pension funds, insurance companies, and sovereign wealth funds, now have ESG mandates that restrict investment in energy-inefficient buildings. Some have set minimum EPC band requirements for new acquisitions. This reduces the buyer pool for poorly rated buildings, which in turn applies downward pressure on prices.

Lender reluctance and financing risk

The brown discount is not only affecting buyers and sellers. Lenders are increasingly scrutinising the energy performance of commercial property when making lending decisions. This is driven by several factors:

• Regulatory risk: A property that cannot be lawfully let due to MEES non-compliance cannot generate rental income. This directly affects the borrower's ability to service the debt and the lender's security value.
• Stranded asset risk: Properties that require substantial capital expenditure to reach Band C may see their net asset value reduced by the cost of the retrofit programme. Lenders are factoring this into their loan-to-value (LTV) calculations.
• ESG reporting obligations: Banks and financial institutions have their own ESG disclosure requirements, including under the EU Taxonomy and the Bank of England's climate stress testing framework. Energy-inefficient buildings in their loan books affect their reported metrics.
• Green lending incentives: Many lenders now offer preferential terms (lower margins, higher LTVs) for energy-efficient buildings, creating a financing cost differential that further widens the gap between green and brown assets.

The practical impact for landlords is that refinancing a property rated D, E, F, or G may become more difficult and more expensive as the proposed Band C deadline approaches. Lenders are already asking borrowers to provide EPC data and retrofit plans as part of loan applications and renewals. A property without a credible pathway to Band C may face reduced LTV ratios, higher interest margins, or in some cases, lender reluctance to refinance at all.

Impact on lease renewals and tenant demand

The brown discount is also visible in the leasing market. Corporate occupiers with sustainability commitments, and many now have them, driven by their own ESG reporting, CSRD obligations, and stakeholder expectations, are increasingly unwilling to occupy buildings with poor energy performance.

This affects landlords in several ways:

• Tenant retention: Existing tenants may choose not to renew leases in buildings that do not meet their sustainability criteria, even if the rent is competitive. The cost of relocating to a better-rated building is increasingly justified by the tenant's own ESG reporting needs.
• Letting incentives: Poorly rated buildings may require higher incentive packages (rent-free periods, fit-out contributions) to attract tenants, reducing the effective rental income.
• Void periods: Buildings with poor EPC ratings may experience longer void periods between tenancies, as the pool of tenants willing to occupy them narrows.
• Rental growth: Market evidence suggests that rental growth for highly rated buildings is outpacing that for poorly rated ones, creating a divergence in income returns that compounds over time.

For property managers, this means that EPC performance is no longer just a compliance issue. It is a commercial issue that directly affects occupancy rates, rental income, and the long-term competitive position of the asset.

The regulatory amplifier

The brown discount exists independently of MEES regulation, market forces alone are driving it through tenant preferences, investor mandates, and lender policies. But MEES acts as an amplifier. The proposed tightening of the MEES threshold from Band E to Band C creates a hard deadline beyond which non-compliant properties cannot be lawfully let at all.

This regulatory backstop converts a gradual market discount into a binary compliance risk. A property rated D is trading at a modest discount today; if the Band C threshold is confirmed for 2028, that same property faces the prospect of becoming unlettable in two years. The market is pricing this forward-looking risk into current values, which is why the brown discount is widening even before the new threshold comes into force.

It is worth reiterating that the Band C 2028 target is a proposed regulatory change, subject to legislative confirmation. However, the direction of travel is clear from Government consultations and policy statements. Prudent investors and landlords are pricing the risk now, rather than waiting for Royal Assent.

What landlords should do

Understanding the brown discount is the first step. Acting on it is the second. For commercial landlords and investors, the priorities are:

1. Quantify your exposure: For every property in your portfolio, know the current EPC band and score, the MEES penalty exposure under the statutory formula, and the estimated cost of reaching Band C. This gives you a clear picture of where the brown discount is most likely to affect your asset values.
2. Model the financial impact: Compare the cost of retrofit against the potential value reduction from the brown discount. In many cases, the cost of improvement is lower than the value at risk from inaction. Factor in improved rental values, reduced void periods, and more favourable financing terms that accompany a better EPC rating.
3. Engage your lenders early: If you are approaching a refinancing or loan renewal, provide your lender with current EPC data and a credible retrofit plan. This demonstrates proactive management and may help secure better terms.
4. Communicate with tenants: For existing tenants approaching lease renewal, demonstrate your commitment to improving the building's energy performance. A clear retrofit timeline can be the difference between a renewal and a vacancy.
5. Use the lender pack: CrowAgent Core generates a lender-ready compliance pack for each property, including the current EPC position, penalty exposure calculation, retrofit scenarios, and NPV analysis. This provides the evidence base that lenders and investors are increasingly requiring.