In short
- EU: every data center of 500 kW IT or more reports PUE, WUE, ERF and REF each year; A–G labels are proposed from 2027.
- Germany: new data centers must reach PUE 1.2; existing ones 1.5 from July 2027 and 1.3 from July 2030. A 2026 draft would relax this.
- Singapore: new capacity is awarded at PUE 1.25 at full IT load; the roadmap points all sites to 1.3.
- China: national average below 1.5 by the end of 2025.
- United States: no federal PUE limit.
The rules at a glance
| Jurisdiction | Instrument | PUE requirement | Status |
|---|---|---|---|
| European Union | Energy Efficiency Directive (EU) 2023/1791 · Delegated Reg. (EU) 2024/1364 | Report annually (no limit) for sites ≥ 500 kW IT | In force |
| European Union | Data centre sustainability rating scheme | A–G labels for PUE and WUE | Proposed |
| Germany | Energy Efficiency Act (EnEfG) § 11 | New ≤ 1.2; existing ≤ 1.5 (2027), ≤ 1.3 (2030) | In force Amendment pending |
| Singapore | IMDA Green DC Roadmap · DC-CFA2 | ≤ 1.3 at full load (target); ≤ 1.25 for new capacity | Target Award condition |
| China | Action plan for green data centers, July 2024 | National average < 1.5 by end 2025 | National target |
| United States | No federal limit · ASHRAE 90.4 where adopted | Design energy performance, code-dependent | Code-dependent |
European Union: report now, labels next
The recast Energy Efficiency Directive (EU) 2023/1791 requires operators of data centers with an installed IT power of at least 500 kW to publish key performance data. Delegated Regulation (EU) 2024/1364 sets out the indicators, which include PUE, WUE, ERF and REF.
- First report: 15 September 2024. Then every year by 15 May.
- Reports go to the European database, or through a national system where one exists.
- There is no EU-wide PUE limit yet. The proposed rating scheme (21 September 2026) would grade sites A to G on PUE and WUE, with the first labels expected from 15 August 2027 if Parliament and Council do not object.
Germany: the first binding PUE limits in the EU
The Energy Efficiency Act (EnEfG) applies to data centers from 300 kW of non-redundant connected load. Section 11 sets PUE, heat reuse and renewable power requirements:
| Requirement | Existing (before 1 Jul 2026) | New (from 1 Jul 2026) |
|---|---|---|
| PUE, annual average | ≤ 1.5 from 1 Jul 2027 ≤ 1.3 from 1 Jul 2030 | ≤ 1.2, within two years of commissioning |
| Reused energy (ERF, EN 50600-4-6) | — | ≥ 10 % (from Jul 2026), 15 % (2027), 20 % (2028) |
| Renewable electricity, balance basis | 50 % from 1 Jan 2024 · 100 % from 1 Jan 2027 | |
Energy used only to upgrade waste heat for reuse, such as a heat pump, is excluded from the PUE calculation.
Singapore: PUE as the price of new capacity
- Green Data Centre Roadmap (IMDA, May 2024): all data centers to reach PUE 1.3 or better at 100 % IT load over the next ten years. A target, not a statutory limit.
- DC-CFA2, the second call for new capacity: applicants must show PUE 1.25 at 100 % IT load, IT equipment to SS 715:2025, BCA-IMDA Green Mark Platinum and a large share of green energy.
China: a national average, tighter rules for new builds
The action plan for the green and low-carbon development of data centers, issued in July 2024 by the NDRC, MIIT and other agencies, aims to bring the national average PUE below 1.5 by the end of 2025 and to raise renewable energy use in data centers by about 10 % a year. Efficiency requirements for new projects are being tightened in the national computing hubs.
United States: no federal PUE limit
There is no federal PUE cap for private data centers. Where state or local energy codes adopt ASHRAE Standard 90.4, the design energy performance of mechanical and electrical systems is regulated instead of a measured PUE. Large operators publish fleet PUE voluntarily.
Compare like with like
The same site can pass one rule and fail another because each measures PUE differently:
- Germany: annual average of measured energy.
- Singapore: PUE at 100 % IT load, closer to a design value.
- EU reporting: annual energy for the reporting year.
A hall designed for 1.2 at full load can report 1.35 in its first year at 30 % load. See What is PUE for the traps.
What it means for a project
- New site in Germany: design for 1.2 as an annual average at the expected load, not at full load. Plan the heat export for the ERF quota from day one.
- Existing German site: measure now. A legacy hall at 1.6 needs containment, higher set points or free cooling before July 2027.
- Any EU site of 500 kW IT or more: meter PUE, WUE, ERF and REF to report by 15 May each year. Labels will make the numbers public.
- Singapore bid: prove 1.25 at full load with the cooling concept and equipment list.
- Due diligence: underwrite the annual PUE at expected load and the cost of meeting the next limit.
Questions about PUE rules
Is there a PUE limit in the EU?
Not yet. The EU requires reporting for sites of 500 kW IT or more. Germany was the first member state to set binding national PUE limits; the proposed EU rating scheme would add A–G labels from 2027.
Does the German limit apply to existing data centers?
Yes. Sites that started operating before 1 July 2026 must reach 1.5 from 1 July 2027 and 1.3 from 1 July 2030, as annual averages. The June 2026 draft would raise these to 1.6 and 1.4.
Does heat reuse lower PUE under the EnEfG?
No, but energy used only to upgrade waste heat, such as a heat pump, is left out of the PUE calculation. Reuse itself is measured as ERF.
Why does Singapore use PUE at full load?
It describes what the design can achieve, which can be checked before a site is built. Annual PUE at partial load is usually higher.
Sources
- Energieeffizienzgesetz (EnEfG), § 11 Klimaneutrale Rechenzentren.
- Directive (EU) 2023/1791; Commission Delegated Regulation (EU) 2024/1364.
- IMDA, Green Data Centre Roadmap (May 2024); DC-CFA2 conditions.
- NDRC and MIIT, action plan for the green and low-carbon development of data centers (July 2024).
- German federal cabinet, EnEfG amendment draft, 24 June 2026.
This guide summarises public rules for orientation and is not legal advice. Check the current legal text for a project decision.