Biomass vs fossil: what's the real carbon footprint on a new build in Luxembourg?

Why does biomass win against fossil fuels from year one?

For a 150 m² new build at roughly 15,000 kWh/yr of heating, oil releases close to 4 tonnes of CO2 and gas about 3 tonnes — against a near-zero balance for wood pellets, since the carbon released is biogenic and reabsorbed by forest regrowth (ADEME, IEA Bioenergy).

The emission factor falls from around 266 g CO2/kWh for heating oil to under 30 g CO2/kWh for certified pellets.

What does the regulation require to stay compliant?

Since 2020, every new biomass boiler installed in Luxembourg must comply with EU regulation 2015/1189 (EcoDesign) and EN 303-5 Class 5: minimum seasonal efficiency, strict NOx and particulate ceilings, mandatory EcoDesign CE marking.

It is a hard prerequisite for Klimabonus 2026 and a clear performance guarantee in your permit file.

How much does Klimabonus 2026 change the project economics?

Klimabonus 2026 pays up to €8,000 for a single-family home (€4,000 without replacement), €6,000 per unit in multi-family buildings (capped at €40,000), and €6,000 for a heat-network connection (capped at €24,000). Stackable bonuses: +15% with a buffer tank, +€1,000 with solar thermal.

Add local commune aids via the official simulator at klima-agence.lu.

Four APS reflexes to lock in the carbon advantage

Four decisions made at concept stage set the CO2 and cost performance for decades.

• Size the pellet silo for at least 1 year of autonomy, with blower-truck access defined in the APS.
• Plan the hydraulic buffer tank from sketch design: +15% bonus and stabilised efficiency.
• Specify ENplus A1 pellets in the technical brief: defined quality, full traceability, low CO2.
• Design a solar thermal back-up from day one: +€1,000 bonus and 10–15% of DHW covered.