What's The Difference Between MEES, CRREM and GRESB?

Three frameworks, three different questions

MEES, CRREM and GRESB come up whenever the energy performance of commercial property is discussed. Each one asks a different question:

FrameworkThe question it answersWho it matters toMEESCan this building be legally let?LandlordsCRREMWhen could this asset fall out of line with a 1.5°C pathway?Investors, valuers, lendersGRESBHow does this fund or portfolio compare with its peers?Fund managers, LPs, lenders

In practice, they often point back to the same buildings.

MEES: the legal floor

What's changed

In June 2026, the government withdrew the proposed 2027 EPC C milestone rather than delaying it. The new target is EPC B by 2031. It applies only to buildings over 1,000 m², and only where the required improvements are cost-effective. For smaller properties, the minimum remains EPC E, with no new deadline announced.

What already applies

The new timeline shouldn't distract from the rules already in force. Since April 2023, properties rated F or G generally cannot be let, including where a lease is already in place.

Why the two dates work differently

The 2031 EPC B target is something landlords can plan for. There's time to assess the works needed and build them into future capex programmes.

The F/G restriction is immediate. If you have qualifying space at F or G, the problem isn't five years away. It can already affect whether that space can be let.

CRREM: the transition-risk clock

What it measures

CRREM looks at a building in terms of transition risk. It gives each asset a Misalignment Year (previously its "stranding year"). This is the point at which the building's carbon intensity is expected to exceed the 1.5°C pathway.

Why it matters

Investors and valuers use this date when assessing an acquisition, a refinancing or an asset's long-term value.

Who controls the calculation

Not necessarily the landlord. A buyer or lender can run the building through their own model and use its CRREM position in their assessment. So the Misalignment Year can start to matter before the landlord has done anything. If an investor expects an asset to need significant investment to stay on the pathway, that feeds into how they price its risk and value.

GRESB: the capital-raising scorecard

What it measures

GRESB assesses the fund or portfolio rather than the individual building. Every year, funds and REITs submit data on governance, energy performance, data coverage and year-on-year improvement. The resulting score lets investors compare managers and portfolios.

Why it matters

For asset managers, that comparison carries more and more weight. Investor and lender expectations are a major reason firms take part, and GRESB performance can come up when managers raise capital.

Why a weak score is more than a reporting issue

When the same LPs compare two managers, the performance of the underlying assets becomes part of the discussion. A poorly performing building can therefore affect the whole fund, not just its own numbers.

Where they overlap

The three frameworks have different purposes and audiences, but one building can be at the centre of all three. A poorly performing asset might:

• already have a MEES problem
• be approaching its CRREM Misalignment Year
• drag down the portfolio's GRESB score

The frameworks don't measure exactly the same thing. But they can all be showing different consequences of the same problem: a building that uses too much energy and needs investment.

Why look at them together

Taken together, MEES, CRREM and GRESB give a fuller picture of each asset:

• MEES: can you let it?
• CRREM: how exposed is it to transition risk?
• GRESB: what effect does it have on the wider portfolio?

Which of the three is causing you the most trouble in your portfolio right now?

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