Annexes 1 to 3 to Commission Delegated Regulation C(2026) 3472 - EU data centre energy (PUE) and water (WUE) efficiency classes, data centre label, and amendments to Delegated Regulation (EU) 2024/1364

Overview

Annex I sets the energy efficiency class of a data centre from PUE and the water efficiency class from WUE, each from A to G. PUE classes: A at 1.15 or below, B 1.15-1.25, C 1.25-1.35, D 1.35-1.5, E 1.5-1.7, F 1.7-1.9 and G above 1.9. WUE classes: A at 0.1 or below, B 0.1-0.2, C 0.2-0.4, D 0.4-0.6, E 0.6-0.8, F 0.8-1.0 and G above 1.0. PUE is determined under point (a) of Annex III of Delegated Regulation (EU) 2024/1364 and WUE under point (b).

Annex II defines the content of the label: data centre name, type, operator, reporting period, location, size category, QR code, entry into operation, the breakdown of energy source (renewable and nuclear energy from on-site, PPA and guarantees of origin, and energy of unidentified source), the PUE and WUE classes and scales, cooling degree days, whether the data centre provides grid flexibility, whether it is 'waste heat reuse ready', and the sums of PPAs and guarantees of origin meeting stricter requirements. Each label is accompanied by a common explanatory document prepared by the Commission, covering the relation of PUE to climate, size and age, the trade-offs between PUE and WUE and the significance of WUE against water stress.

Annex III amends the reporting annexes of Regulation 2024/1364. Location is reported as a NUTS3 code; a data centre not yet operating reports 'DESIGN' and the estimated year of entry into operation. Certification of reported data is defined, distinguishing self-certification from third-party certification. Total energy consumption (EDC) is measured under EN 50600-4-2 at the input before the supply transfer switchgear, and energy from back-up generators (EDC-BG) is reported separately. IT energy (EIT) is measured preferably at Category 3 (rack plug or power strip) and, if impossible, at Category 2 (PDU).

Water is measured under EN 50600-4-9 Category 1 and WUE is now freshwater input (WIN-FRE) / EIT. A new Low-Emission Energy Factor is LEEF = ELE-TOT/EDC, where ELE-TOT sums renewable and nuclear energy from guarantees of origin, PPAs and on-site sources. Under the amendment to Annex IV, public information at Member State and Union level includes the number of reporting data centres, size distribution, total IT power, total energy and water consumption and the averages of PUE, WUE, ERF, REF and LEEF (weighted by total energy consumption, with type and size breakdowns).

Key points

1. PUE classes: A <= 1.15; B 1.15-1.25; C 1.25-1.35; D 1.35-1.5; E 1.5-1.7; F 1.7-1.9; G > 1.9.
2. WUE classes: A <= 0.1; B 0.1-0.2; C 0.2-0.4; D 0.4-0.6; E 0.6-0.8; F 0.8-1.0; G > 1.0.
3. WUE is redefined on freshwater: WUE = WIN-FRE / EIT (IT energy expressed in kWh); freshwater input is measured by EN 50600-4-9 Category 1, and return flows from recirculating cooling systems are not added to WIN or WIN-FRE.
4. The new Low-Emission Energy Factor is LEEF = ELE-TOT / EDC, where ELE-TOT sums renewable and nuclear energy from guarantees of origin, PPAs and on-site sources.
5. The label shows PUE and WUE classes, cooling degree days, grid flexibility provision, waste-heat-reuse readiness, size category, QR code and energy-source breakdown.
6. Location is reported as the EU NUTS3 code; a data centre not yet operating reports 'DESIGN' plus estimated year of entry into operation.
7. Energy from generators and back-up generators (EDC-BG) is reported separately, covering both normal operation and generator maintenance and testing.
8. EDC is measured before the supply transfer switchgear at the primary, secondary and every additional supply (for example back-up generation); IT energy (EIT) is measured at the rack connection point (Category 3), or at PDUs (Category 2) if that is impossible.
9. Stricter-requirement items (NC) are reported separately: for guarantees of origin the production period must match the consumption period and production must be in the same bidding zone or Member State; for PPAs production may be in an interconnected bidding zone. In both cases the asset must have been commissioned or substantially refurbished no more than 10 calendar years before the reporting year.
10. Cooling degree days are now filled automatically by the European database from the location using the Eurostat and JRC method; LEEF joins the weighted public aggregates, and breakdowns by type or size are presented only for categories with at least three data centres.

Using it in design

• Translate PUE and WUE targets into A-G classes: class A needs a design PUE of 1.15 or below and WUE of 0.1 or below; the class D boundary is 1.5 and 0.6. Write the class target into the design specification.
• Design measurement points so that WUE is based on freshwater input (WIN-FRE) with the source identified, leaving return flows from recirculating cooling outside the meter logic.
• Plan the metering infrastructure to EN 50600-4-2 and 4-9: EDC at the supply transfer switchgear input, EIT at the rack (or at least the PDU), and a separate EDC-BG measurement for generators.
• For waste heat reuse readiness consider heat exchangers, dedicated hydraulic loops and thermal metering in the design; the label shows this readiness.
• In energy supply contracts track separately the stricter-requirement (NC) share of PPAs and guarantees of origin (temporal matching and same bidding zone for guarantees of origin, assets under 10 years old for both) and make sure guarantees of origin are cancelled in your name.
• Add the DESIGN status and the NUTS3 location code to your project data for reporting.

Who should read it

Designers, operations and compliance teams meeting the EU data centre rating label and its reporting requirements.

Document contents

1. Annex I Energy and water efficiency classes: Table 1 (PUE classes), Table 2 (WUE classes)
2. Annex II Label for data centres: label content (I-XVIII)
3. Annex II, point 3 Common explanatory document accompanying each label
4. Annex III (amendments to the Annexes of Delegated Regulation (EU) 2024/1364): amendments to Annex I (location, entry into operation, certification of reported data)
5. Annex III: amendments to Annex II: EDC and EDC-BG, EIT, flexibility functions to the grid
6. Annex III: WIN and WIN-FRE, waste heat reuse ready, cooling degree days
7. Annex III: ERES and ENUC (guarantees of origin, PPA, on-site) and ELE-TOT
8. Annex III: amendments to Annex III: WUE and LEEF formulas
9. Annex III: amendments to Annex IV: publicly available aggregated information

Related standards

• Delegated Regulation (EU) 2024/1364
• EN 50600-4-2
• EN 50600-4-9
• Directive 2000/60/EC

Read the document

Publication details

Authors

European Commission

Publisher

European Commission

Year

2026

Document number

C(2026) 3472 final - Annexes 1 to 3

Document language

English

Source type

Government / public

Access

Open licence — downloadable

Licence

EU reuse (2011/833/EU) — reuse permitted with acknowledgement of the source

Licence evidence

eur-lex.europa.eu

Citation