RegulationFor architects

EcoDesign 2022 and EN 303-5 Class 5: what your Luxembourg building permit now requires

What every architect in Luxembourg must verify for a compliant biomass project: EcoDesign, EN 303-5 Class 5, and the Klimabonus 2026 stack.

Updated 24 July 2026·4 min read

EcoDesign 2022: what really changes?

EU Regulation 2015/1189 applies to every new biomass boiler placed on the EU market since 1 January 2022. It sets a minimum seasonal efficiency and caps for emissions (CO, NOx, particles, OGC). In practice, a boiler without EcoDesign cannot be installed in a new Luxembourg project.

For the architect, this means the manufacturer's technical sheet must show EcoDesign compliance from the APS stage. Without it, the client's file is incomplete.

  • Seasonal efficiency ηs ≥ 75% (wood) or 79% (pellets) depending on class.
  • Check PM, OGC, CO and NOx caps on the manufacturer sheet.
  • Reference: EU Regulation 2015/1189.

EN 303-5 Class 5: why require it in the permit?

EN 303-5 ranks solid-fuel boilers from 1 to 5, Class 5 being the strictest. It is often used as a reference by municipalities and insurers. Writing it into the specification saves time on site.

For a new residential project in Luxembourg, requiring Class 5 in the permit file is a strong signal: the chosen boiler will remain compatible with future air-quality targets.

  • Class 5 = best compromise between efficiency and emissions on the market.
  • Attach the manufacturer's certificate or an EN 303-5 test report.
  • Source: CEN/CENELEC.

ENplus A1: the right reflex for pellets

Fuel quality matters as much as the boiler. ENplus A1 certification guarantees moisture below 10%, a stable calorific value and full traceability. In a quality-driven project, it is a real asset for property value.

  • ENplus A1 = premium-grade pellets.
  • Request the delivery certificate from the supplier.
  • Source: ENplus.

Klimabonus 2026: the financial lever

In Luxembourg, only PELLET boilers qualify for Klimabonus 2026. For a single-family home, the grant goes up to €8,000 (€4,000 without replacing an old system). For collective housing, up to €6,000 per unit (cap €40,000). For a heat network, up to €6,000 (cap €24,000). This amount can be combined with municipal grants.

  • +15% grant with a buffer tank.
  • +€1,000 flat bonus with solar thermal backup.
  • Municipal grants are stackable: simulate on aides.klima-agence.lu.
  • Source: Guichet.lu.

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