Key takeaways
- 24 July 2026 is a hard date, not a "direction of travel". From that day, non-compliant fans cannot be placed on the EU market.
- The formula changed: for Pe < 10 kW, ηmin = 4.56·ln(Pe) − 10.5 + N. Reusing the 327/2011 constants is wrong in both directions.
- Grades rose across the board: axial static 50, total 64; other centrifugal 64/67. Mixed-flow N slides with flow angle; cross flow drops the formula and is fixed at 21%.
- The η you compare is not the one on the test report: the regulation's η carries Cp, Cc and Cguard, and skipping them fails a compliant product.
- Compliance is more than efficiency — Annex II points 2 to 5 add product information, spare-part and dismantling requirements.
1. Dates and scope
(EU) 2024/1834 was adopted on 3 July 2024 and applies from 24 July 2026, repealing (EU) No 327/2011. It covers fans with electric input power ≥ 125 W and ≤ 500 kW at the best efficiency point (BEP), including fans integrated into other products (AHUs, heat pumps, chillers, enclosures). Jet fans have a separate 750 W lower bound.
Exclusions include: potentially explosive atmospheres (ATEX); fire-emergency-only fans able to run 1 hour at 300 °C and above; nuclear installations; military and civil-defence shelters; gas temperatures above 100 °C or below −40 °C; supply voltage above 1 000 V AC; toxic/corrosive/flammable gas handling; and battery-powered, hand-held and hand-guided equipment. Fans with a best efficiency point at 8 000 rpm or more are also out of scope.
A common statement that needs correcting: the industry used to say "ErP fans have no single switch-over date, only a gradual tightening." That held under 327/2011, but 2024/1834 sets a single application date of 24 July 2026. Planning a product changeover as if there were no hard date runs out of time.
2. How ηmin is calculated: five cases
Most fans use one logarithmic formula, but four carve-outs sit around it. Applying the general case to a cross-flow or low-specific-speed fan produces a number the regulation never asked for.
One further carve-out: centrifugal fans with specific speed σBEP < 0.12, electric input power below 10 kW, measured in category B or D against total pressure, are judged against ηmin = 2.95 · σBEP + 0.2. For σ = 0.10 that is 49.5%, well below what the general curve would demand of the same machine.
Mind the boundary. The regulation splits at Pe < 10 and Pe ≥ 10 kW. A fan sitting exactly at 10 kW takes the high-power equation.
→ Compute ηmin and the corrected η with the calculator: choose fan type and category, enter Pe and measured efficiency, and get the threshold, the corrected efficiency, the verdict and the margin.
3. Minimum efficiency grades N (Annex II, Table 1)
Classification follows geometry, not product naming. Annex III fixes the boundaries: an impeller is axial below 20°, mixed flow from 20° to 70°, centrifugal at 70° and above; a centrifugal blade is backward curved up to β₂ = 50°, backward inclined to 90°, forward curved beyond.
| Fan type (regulation wording) | A / C static | B / D total |
|---|---|---|
| Axial fans | 50 | 64 |
| Forward curved < 5 kW and backward inclined | 52 | 57 |
| Other centrifugal fans | 64 | 67 |
| Mixed flow fans | 57 + 7·(α − 45)/25 | 67 |
| Jet fans ≥ 750 W (category E) | 50 | |
| Cross flow | no grade — fixed 21 % total | |
The trap in row two. "Forward curved" is only in the 52 / 57 band below 5 kW. A forward-curved impeller at 5 kW or above falls into other centrifugal fans and is judged against 64 / 67 — a jump of twelve grade points at a single power threshold, with nothing changed in the fan itself.
Modifier factors (applied to N)
| Characteristic | Factor | Definition |
|---|---|---|
| Dual use | 0.9 | Normal ventilation plus emergency duty under Article 1(3)(b) |
| Reversible | 0.85 | Reaches ≥ 80% of nominal forward volume flow in reverse |
| Low noise | 0.9 | Axial, Pe ≥ 10 kW, characteristic noise value L ≤ 32 dB(A) at BEP |
Multiple factors compound. A 30 kW low-noise axial fan takes N from 50 to 45, moving the threshold from 51.14% to 46.14%.
4. The η you compare is not the one on the test report
This is where most first-pass compliance checks go wrong. The regulation's η carries three correction factors, and two of them can move a borderline product across the line.
| Factor | Value | Applies when |
|---|---|---|
| Cp | 0.9 | DC motor rated below 100 V with the AC/DC converter outside the fan |
| Cp | 1.0 | Everything else |
| Cc | 1.04 | VSD included in conformity assessment, Pe ≥ 5 kW |
| Cc | 1 + 0.0812·Pe−0.5 | VSD included in conformity assessment, Pe < 5 kW |
| Cc | 1 | No variable speed drive |
| Cguard | 1.00 → 1.15 | Non-removable guard, scaled by opening dimension e from > 30 mm down to ≤ 8 mm |
The part-load term is not small at the bottom of the range. A 0.5 kW fan with an assessed drive earns Cc = 1.115 — an 11.5% uplift on measured efficiency. A fine-mesh guard at e = 8 mm adds another 15%. Ignore both and a compliant product reads as a failure; claim both without the matching assessment documents and market surveillance will not accept it either.
5. Six ways a compliance check goes wrong
6. Timeline
- 2024-07-03(EU) 2024/1834 adoptedPublished by the European Commission, repealing (EU) No 327/2011.
- 2026-07-24Requirements applyMinimum efficiency, product information, repairability and dismantling requirements all bite; non-compliant fans can no longer be placed on the market.
- 2027-07-24Embedded-fan grace period closesA fan placed solely for integration into another product, within the first year, already compliant with 327/2011, with its first unit shipped before 24 July 2026 — all four conditions must hold.
- 2037-07-24Spare-part exemption endsReplacement fans for units placed before July 2026 stay exempt from the efficiency requirements where no compliant replacement fits, but must still meet the information requirements.
7. What buyers and OEMs should ask the supplier
| Item | What to request | Why |
|---|---|---|
| Duty-point data | BEP qv, Δp, Pe and the full P-Q and efficiency curves | ηmin is taken at the BEP electric input power; catalogue peaks are not enough |
| Efficiency basis | Whether the declared η already includes Cp / Cc / Cguard, and each value | Different conventions give different compliance conclusions |
| Classification | Flow angle α, blade angle β₂, or the declared regulation class | N is read from Table 1 by geometry, not product name |
| Drive scope | Whether the VSD is in the fan's conformity assessment | Determines whether Cc = 1.04 or the low-power form applies |
| Guard | Whether it is non-removable and the opening dimension e | Determines Cguard, up to a 15% difference |
| Documentation | Technical data sheet, free-access web link or QR code, spare-part and dismantling information | Mandatory under Annex II points 2 to 5 |
For AHU, heat-pump, cold-chain and enclosure OEMs, the real 2026 workload is not "fit a more efficient fan" but re-checking every in-production model at its duty point and getting the documentation to match. The embedded-fan transition runs at the latest to 24 July 2027 and requires the first unit before July 2026 — the design-change window is shorter than most teams assume.
For duty-point checks or replacement work, LONGWELL EC platforms can be evaluated: LWBE3G backward-curved centrifugal, LWAE3G EC axial, and AHU plug-fan modules, each supplied with BEP duty-point data and curves for a given airflow, static pressure, voltage and control method for the ηmin check above. The efficiency basis is stated per Annex III 6.1 rather than as a blanket claim.
For projects replacing imported models, LONGWELL can provide replacement candidates for many mainstream brands as a replacement candidate; final selection is confirmed by duty point, voltage/control, mounting and project validation.
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FAQ
Can LONGWELL EC fans serve as a replacement for an ErP 2026 project?
Is there a single date on which ErP 2026 takes effect?
How is ηmin actually calculated?
Can the test-report efficiency be compared directly to ηmin?
Does a motor efficiency class (IE5, etc.) prove whole-fan compliance?
Need a duty-point ErP 2026 check or a replacement model?
Send the current model, airflow, static pressure, voltage, control method, mounting and annual volume, and LONGWELL can match a suitable platform and supply BEP duty-point data and curves.
Email sales@longwellfans.comOpen the calculatorSource
Commission Regulation (EU) 2024/1834 of 3 July 2024, Articles 1–2, Annex II point 1 (with Table 1) and Annex III points 4 to 8. Full text: EUR-Lex, CELEX 32024R1834.
This is an engineering interpretation to estimate the compliance threshold; it does not replace a test report, a harmonised standard or a conformity assessment. Fan classification, correction-factor values and declared values remain the manufacturer's responsibility under Article 4. Market-surveillance tolerances are in Annex IV.