EU data centre rating: what the A to G label grades, and when

Key takeaways

• The EU rating grades two numbers. Power usage effectiveness (PUE) and water usage effectiveness (WUE) each get a class from A to G in Annex I of C(2026) 3472 final. Class A needs a PUE of 1.15 or less and a WUE of 0.1 or less. The label has no overall score.
• The act is adopted but not in force. The Commission adopted it on 21 September 2026, and on 6 October Parliament extended its scrutiny by two months (procedure 2026/2895(DEA)). If it enters into force as drafted, the EU database would generate and supply labels by 15 August 2027, and every year after, for centres that have submitted the required data.
• The label would make public some site data that the 2024 rules keep confidential, such as both classes and where the site’s energy came from.
• On our reading, the first label would describe calendar year 2026, reported by 15 May 2027. Metering and documentation can still move a class. A plant upgrade finished in 2027 would first show on the 2028 label.
• The adopted WUE formula divides cubic metres of freshwater by IT energy in kWh, where the 2024 formula used MWh. Read literally, almost every site would land in class A. Ask for clarification before you plan around the water class.

A data centre with a PUE of 1.35 would get a C on the EU’s new sustainability label. At 1.36, the EU average the Commission reported for 2024, it would get a D. PUE is total facility energy divided by the energy used by the IT equipment. A PUE of 1.36 means 36 kWh of overhead, mainly cooling and power conversion losses, for every 100 kWh the IT equipment draws. The class boundaries come from Annex I of the Commission’s delegated act C(2026) 3472 final, adopted on 21 September 2026. The average comes from the Commission’s report of the same day on the first reporting period (section 2.2.1).

This article reads the act itself: what it grades, what it makes public, which measurements decide a class, and when the first label would arrive. It is a reading of the adopted text for planning, not legal advice. The reporting duty underneath the rating is covered in our EED reporting guide, and the status of each related rule is in our regulation tracker.

Where the act stands on 8 October 2026

The Commission adopted the act on 21 September, and it has not entered into force. Under Article 34(6) of the Energy Efficiency Directive, a delegated act enters into force only if neither Parliament nor Council objects within two months. Either of them can extend that period by two months. Parliament’s procedure file records the initial two-month examination from 21 September, an extension at Parliament’s request on 6 October, and referral to committee announced on 7 October. If no objection comes, Article 7 of the act sets entry into force on the twentieth day after publication in the Official Journal.

Until then, cite it as C(2026) 3472 final. Its cover still reads “Commission Delegated Regulation (EU) …/…”. A footnote inside the text, and the Commission’s report, refer to “(EU) 2026/7000”, but no Official Journal number has been assigned yet.

What the label grades

Article 1 tells the European database on data centres to rate each site with an electronic label. It uses one class for PUE and one for WUE. Both use the formulas in Annex III of Delegated Regulation (EU) 2024/1364, the 2024 reporting rules. WUE is water used per unit of IT energy. The act changes it to count freshwater only.

The PUE scale is tight at the top. Four of its six boundaries sit between 1.15 and 1.5. Take a site with 1 MW of IT load running all year, which is 8,760 MWh of IT energy. Each 0.01 of PUE is then 87.6 MWh of overhead a year (our arithmetic). The 2024 EU average of 1.36 sits 0.01 above the C boundary.

Nothing else on the label is graded. The act’s explanatory memorandum says the thresholds were set from data submitted in the first reporting period and from existing standards and benchmarks. Article 6 orders a review by 31 December 2028 and every three years after. Among other options, that review may consider an indicator that aggregates the others and rates each site’s overall sustainability, or (partial) certification or auditing of the reported data. None of these is in the adopted text. For published averages by size of site, see our reading of the 2025 dashboard.

What the label makes public

Annex II lists 18 items for the label. Two are classes and two are the A to G scales they sit on. The others are facts the operator already reports, or values the database adds.

This changes what a customer or competitor can see. Article 5(5) of the 2024 regulation keeps all individual site data in the database confidential. The act rewrites that paragraph to exempt the information on the label, in the form in which it appears there. Labels would be public in the database in all official EU languages. Article 4 would also require operators to give the label to anyone who asks, through their own free website or the database. It would forbid labels that mimic the official one, so check sales material for anything that looks like it.

The region is a NUTS 3 code, the EU’s statistical unit at roughly province or county level. Cooling degree days, a measure of how hot a location’s year was, are filled in by the database. They sit next to the class as context and do not change it. Each label also comes with one Commission document, common to all labels. Annex II lists nine topics it must explain, among them how PUE relates to climate and the trade-off between PUE and WUE.

The energy breakdown separates certificates from contracted and on-site supply. A guarantee of origin, a certificate that a unit of energy came from a given source, counts only if it relates to production in a bidding zone connected to the data centre’s own. The stricter subset takes power purchase agreements with plants commissioned, or substantially refurbished, no more than 10 calendar years before the reporting year. Certificates in that subset must meet the same 10-year plant test, match the consumption period at the finest time resolution issued in that Member State, and come from the same bidding zone or Member State. Nuclear is shown alongside renewables. A reader will see how much energy comes from plants up to 10 years old, how much of the certificate share is also matched to the consumption period, and how much the operator did not identify.

What decides your class

A class is a ratio, so it moves with both halves of the fraction. Annex III of the act rewrites the measurement rules in the 2024 regulation. These are the changes that can move a site across a boundary.

Total energy is measured at the input of the data centre system, before the supply transfer switchgear, at every supply including back-up generation. Energy from generators is also reported separately, and that figure includes maintenance runs. Where the building has another main use, such as offices, only the data centre’s share counts.

Energy used to raise the temperature of heat that is then reused is subtracted from total energy. The act names heat pumps, boosters, heat transformers, heat exchangers and heat network equipment. On our reading, a heat pump that lifts server heat for a district network therefore does not count against PUE, provided the heat is reported as reused and you can show how much energy the pump used. Meter it on its own.

IT energy is measured where the racks connect, at the power strip or rack plug (category 3 under the EN 50600-4-2 standard). Where that is not possible, the act accepts the sum at each power distribution unit (category 2). Record which one you use, because it sets the bottom of the fraction.

Under the act, WUE counts freshwater input only. It defines freshwater by its salinity, “regardless of its origin”, so, on our reading, treated or recycled water of freshwater quality still counts and seawater does not. If your Member State defines freshwater in national law, that definition applies. Return flows from recirculating cooling systems are left out.

Colocation operators who cannot gather data for the whole computer room floor must estimate and state the share of floor area their figures cover. The 2024 rules allowed this only for the first two reporting periods. The act drops that limit. The 2024 option for operators to gather tenant figures through an anonymous internal reporting mechanism stays.

One line needs checking before anyone plans around the water class. The adopted formula is freshwater input divided by IT energy, with water in cubic metres and IT energy “expressed in kWh”. The 2024 formula divided by IT energy in MWh. The Commission’s report gives the 2024 average as 0.58 m³/MWh, which is 0.58 litres per kWh. Divided by kWh instead, the same site would score 0.00058, well inside class A. The memorandum says the thresholds were set from first-period data, which were reported per MWh, so the stated unit and the class limits do not obviously fit together. Ask your national contact point, or the Commission’s data-centre team listed on its energy performance page, before you treat a water class as settled.

When the first label would arrive

Article 3 of the act says that by 15 August 2027 and every year thereafter, the database shall generate a label. It goes to data centres that have reported under Article 3 of the 2024 regulation. That article sets the reporting deadline at 15 May each year. It also says the data cover the calendar year immediately before. Read together, the label due by 15 August 2027 would most likely describe calendar year 2026. This is our reading, because the act leaves the reporting period on each label to the database.

A label is valid from 15 August of the year it is issued until 15 August of the next. If a Member State has not confirmed by 15 August that reporting on its territory is complete, the old label stays valid until a new one is issued, at the latest until 31 December. We found no transitional clause, so whether the new measurement rules apply to the May 2027 report depends on when the act is published.

Under the act, sites below the 500 kW threshold could join voluntarily by reporting by the same deadline. Sites not yet operating could report the values they are designed to reach after two calendar years of operation. They switch to measured values from their first year.

Two defence carve-outs sit side by side. Article 12(2) of the Directive is in force now. It says the publication duty does not apply to “data centres used for, or providing their services exclusively with the final aim of, defence and civil protection.” The act would add a separate exemption from reporting to the EU database, for a centre that “is used for, or provides its services exclusively with the final aim of, supporting the defence and civil protection of a Member State”, in whichever Member State it is located. Neither text exempts a site because one of its customers works in defence.

Three EU tracks at three stages

What to do before August 2027

1. Confirm scope. Check installed IT power against the 500 kW threshold, and test the Directive’s Article 12(2) exclusion and the act’s database exemption against what the site actually does.
2. Fix the meter map for the rest of 2026. Write down where total energy and IT energy are measured, which EN 50600-4-2 category applies, and how generator runs are captured.
3. If you reuse heat, meter the heat pumps or boosters separately so their energy can come off total energy.
4. Split freshwater from total water input. Check whether your Member State defines freshwater, and keep recirculating return flows out.
5. Put energy contracts in order. Hold cancelled guarantees of origin in your name, PPA volumes, the commissioning dates of the plants behind them and the time resolution of the certificates. Energy you cannot attribute appears on the label as unidentified.
6. Decide the two yes or no flags on evidence. Waste heat reuse ready means heat extraction built to the site boundary, for example heat exchangers, dedicated hydraulic loops and thermal metering. A heat network outside the fence is not required. Grid flexibility covers functions such as peak demand shifting or firm frequency response.
7. Prepare to serve the label from your website or a database link, and remove anything in sales material that imitates it.
8. Watch the Official Journal, ask about the WUE unit, and send evidence on minimum standards through Have Your Say initiative 19293 before 14 December 2026.

The calendar limits what an engineering project can do for the first label. A chiller replacement or a move to dry cooling finished during 2027 changes the energy and water metered in 2027. On that reading, those figures would be graded on the label due by 15 August 2028. For the label due a year earlier, the operating year is already three quarters over.

Sources

• European Commission, C(2026) 3472 final, delegated regulation and Annexes I to III, 21 September 2026 (EUR-Lex record)
• European Parliament, Legislative Observatory, procedure 2026/2895(DEA)
• Directive (EU) 2023/1791, consolidated text of 5 August 2026, Articles 12, 33 and 34
• Commission Delegated Regulation (EU) 2024/1364, Article 3, Article 5 and Annexes II to IV
• European Commission, COM(2026) 500, report on the energy efficiency of data centres, 21 September 2026 (Council copy ST 13443/26)
• European Commission, minimum performance standards consultation notice, 21 September 2026
• European Commission, Have Your Say initiative 19293
• European Commission, energy performance of data centres