Multi-fuel boiler in Luxembourg: wood + pellets, the dual-fuel approach that secures a rural project
How to combine firewood and pellets in a new build or renovation in Luxembourg. Standards, sizing, and Klimabonus 2026 to know from APS.
Why combine two fuels from APS onwards?
Energy autonomy becomes a design driver from the very first sketch in any rural project. Firewood and pellets answer to different markets: the stere depends on local supply, the pellet tonne follows a European index.
Combining both spreads the risk and keeps a margin if one supply chain tightens. For the architect, it is also a heritage value: the building stays heatable even if one fuel stream breaks.
Wood + pellets: who qualifies for Klimabonus 2026?
Klimabonus 2026 funds the pellet boiler only — never firewood or wood chips. For a single-family home, the grant reaches €8,000 if it replaces an old installation, €4,000 otherwise.
In multi-unit housing, count €6,000 per unit (cap €40,000). Firewood remains a non-subsidised complement to fold into the global operating budget.
Four design reflexes for APS
Four concrete levers to turn dual-fuel into real heating comfort without losing compliance.
- Boiler room sized for two silos: bulk pellets (≥ 4 m³ for one season in a 150 m² house) + ventilated log store within 10 m
- Buffer tank ≥ 20 l/kW to dampen cycles and host the thermal solar loop
- EN 303-5 Class 5 + EU regulation 2015/1189 (EcoDesign) in the specification — conformity baseline for boilers < 500 kW
- ENplus A1 pellets: NCV ≥ 4.6 kWh/kg, moisture ≤ 10 %, ash ≤ 0.7 %
How to budget the project accurately?
Three levers to run in parallel so no subsidy is missed and eligibility is secured.
- Klima-Agence official simulator to stack state Klimabonus and communal grants
- myenergy Luxembourg for the energy pre-diagnosis
- Specification quoting EN 303-5 and regulation 2015/1189 to validate eligibility
Sources
Need personalised advice?
Our team supports you with selection, sizing and subsidy paperwork.