Technical glossary

Biomass boiler vocabulary

Concise factual definitions to understand pellets, Class 5, modulation, seasonal efficiency and energy grants.

Pellet boilerWood pellet boiler · Chaudière à granulés: Biomass boiler with automatic feed of wood pellets (ENplus A1 pellets). Tatano offers pellet boilers from 15 to 3,000 kW, energy class A++, with 1:4 modulation (eligible for the Klimabonus in Luxembourg). Common synonym: wood pellet boiler.
Pellet insertPellet fireplace insert · Insert à pellet: Closed firebox fitted into an existing fireplace, burning pellets or logs, with a water heat exchanger to supply radiators or underfloor heating. Tatano Kalorino KS pellet inserts cover 15–30 kW, combining radiant room heat with an integrated hydraulic circuit.
Wood boilerWood-fired boiler · Biomass wood boiler: Biomass boiler burning wood in the form of logs, wood chips or pellets, depending on the model. Tatano manufactures wood boilers from 15 to 3,000 kW, compliant with EN 303-5 Class 5 and EcoDesign. Generic term covering logs, wood chips and pellets.
Solar thermal panelsSolar panels · Solar collectors · Solar thermal: Roof-mounted collectors that convert solar radiation into heat for domestic hot water or supplementary space heating. Tatano offers forced- or natural-circulation solar systems that can be coupled with any biomass boiler via a buffer tank.
Solar storage tankSolar water heater · Solar DHW tank · Solar cylinder: Water tank (typically 200–500 L) heated by solar thermal panels to produce domestic hot water and/or supplementary space heating. Coupled with a Tatano pellet boiler or wood boiler via a buffer tank — solar takes over in summer.
Wood pelletsPellets · Pellet: Cylindrical fuel 6 mm in diameter, made by compressing residual sawdust without chemical binders. Net calorific value (NCV) ≈ 4.8 kWh/kg, moisture < 10%.
ENplus A1: European certification for top-quality wood pellets (NCV ≥ 4.6 kWh/kg, ash ≤ 0.7%, moisture ≤ 10%). The standard required by most modern domestic boilers.
Wood chipsWoodchips · Forest chips · Cippato: Fuel shredded from forest or sawmill wood. Quality standard: ISO 17225-4. Particle size 3-50 mm, moisture 20-35%. More economical than pellets, but requires a larger silo.
LogsFirewood · Split logs: Split and dried wood, 33-50 cm long, ideal moisture < 20% (2 years of drying). NCV 4.2-4.5 kWh/kg for hardwood species (oak, beech, hornbeam). The cheapest fuel per kWh when sourced locally.
EN 303-5 Class 5Class 5 · Classe 5: European standard defining the highest performance class for solid-fuel boilers ≤ 500 kW: efficiency ≥ 87%, CO emissions ≤ 500 mg/m³, particulates ≤ 40 mg/m³ (at 10% O₂). A condition for energy grant eligibility in BeLuxFr.
EcoDesign ErPRegulation 2015/1189 · Ecodesign: European Regulation 2015/1189, mandatory since 2020 for every solid-fuel boiler placed on the EU market. Sets minimum thresholds for seasonal efficiency (ηs ≥ 75% for pellets) and emissions.
Energy Label ErPEnergy label: European Regulation 2015/1187 requiring the A+++ → G energy label to be visible on every boiler product. Modern pellet boilers reach A++; log boilers A+.
Seasonal efficiency (ηs)Seasonal efficiency · ηs: Average efficiency measured over a full heating season, including start-up, shutdown and part-load losses. More representative than nominal efficiency. A Tatano Class 5 boiler typically reaches ηs 88-93%.
1:4 modulationModulation · Modulation range: The boiler's ability to adjust its output between 25% and 100% of its nominal output. Avoids short on/off cycles that degrade efficiency and service life. A 30 kW boiler with 1:4 modulation operates between 7.5 and 30 kW.
Buffer tankHydraulic buffer · Buffer · Thermal store: Water tank (typically 500-2,000 L) that stores the heat produced by the boiler and releases it to the heat emitters. Essential for log boilers, strongly recommended for pellets. Also enables solar thermal coupling.
AugerFeed auger · Screw conveyor: Helical mechanism that carries pellets or wood chips from the silo to the combustion chamber. A wear part checked at the annual service. Variable speed to match the fuel flow to the output required.
Klimabonus WunnenKlimabonus · Klimabonus 2026: Luxembourg financial aid paid by the Ministry of the Environment for energy renovation. For a pellet boiler in a single-family home: a flat €8,000 when replacing a fossil-fuel system, €4,000 without. Application deadline: 4 years.
MaPrimeRénov'Prime Rénov · MPR: French energy renovation grant distributed by ANAH. Since 01/01/2026, a biomass boiler is no longer eligible as a single measure: only within a whole-home renovation (rénovation d'ampleur). Still available: CEE, 5.5% VAT and éco-PTZ.
Buildings ProgrammeProgramme Bâtiments · Das Gebäudeprogramm: Swiss subsidy programme for energy renovation, funded by the CO₂ levy and administered by the cantons. Replacing a fossil-fuel heating system with a wood boiler is subsidised depending on the canton (e.g. Vaud M-03: CHF 8,500; Geneva: CHF 3,000 + 50/kW). The application must be filed BEFORE the works.
Thermal kWThermal kilowatt · kWth: Unit of a boiler's instantaneous output. 1 kW = the capacity to produce 1,000 W of heat continuously. A 150 m² BBC (low-energy) house typically needs 9-12 kW, an average renovation 18-25 kW.
Useful kWhUseful kilowatt-hour: Thermal energy actually delivered to the home (after losses). Allows fuel costs to be compared for the same delivered output. Pellets ≈ 7.7 cents per useful kWh in Luxembourg in 2026.
NCVNet calorific value · Lower heating value: Quantity of heat released by the complete combustion of 1 kg of fuel, without recovering the condensation heat of the flue gases. ENplus A1 pellets: 4.8 kWh/kg; dry hardwood logs: 4.2 kWh/kg; wood chips at 30% moisture: 3.5 kWh/kg.
Particulate matter (PM)PM2.5 · Fine particles · Dust: Fine solid particles suspended in combustion flue gases, measured in mg/m³ or mg/Nm³. EN 303-5 Class 5 caps them at 40 mg/m³ (the Klimabonus requires ≤ 8 mg/m³).
Nm³Normal cubic metre: Cubic metre of gas measured under standard conditions (0 °C, 1,013 hPa). Unit used to normalise pollutant concentrations in flue gases regardless of actual dilution.
Heat exchangerExchanger: Component that transfers thermal energy from the combustion flue gases to the heating water circuit. Its cleanliness directly determines efficiency — hence the mandatory annual maintenance.
InsertFireplace insert · Closed firebox: Closed cast-iron or steel firebox fitted into an existing fireplace or a masonry surround. Tatano Kalorino KS inserts produce room heat (radiation) and hot water for radiators (integrated heat exchanger).
Thermo-fireplaceHydraulic fireplace · Water-jacketed fireplace: Insert variant fitted with a water heat exchanger so that the appliance can be connected to the central heating circuit. Suits homes that want to keep the look of a fireplace while supplying all the radiators.
Boiler roomPlant room · Technical room: Room dedicated to the boiler, its fuel silo, its circulating pumps and its hydraulic buffer. Must comply with strict rules on ventilation (air inlet/outlet), fire resistance and accessibility for maintenance.
CogenerationCHP · Combined heat and power: Simultaneous production of heat and electricity from the same fuel. Available from a few hundred thermal kW for Tatano industrial sites. Raises overall energy efficiency above 80%.
District heating networkDistrict heating · Heat network: Centralised heat production (0.5-3 MW biomass boiler plant) distributed to several buildings through a network of insulated pipes. Typical applications: new neighbourhood, business park, multi-unit residential complex.

Grants in Luxembourg

In Luxembourg, the Klimabonus 2026 scheme subsidises the installation of a wood-pellet boiler in an existing residential building. Since 1 January 2026, only PELLET boilers remain eligible — log-fired and wood-chip boilers have been removed from the support scheme (aligning with the EU RED directive).

Klimabonus 2026 — wood-pellet boiler

Up to €8,000 for a single-family home (€4,000 if no old installation is being replaced); €6,000 per dwelling in a multi-unit building (capped at €40,000). Bonuses: +15% of the grant with a buffer tank (30 l/kW), +€1,000 flat-rate with solar thermal.

Reserved for EXISTING residential buildings (housing — neither new-build nor commercial)
Pellet boiler with automatic feed and ignition: particulates ≤ 8 mg/m³, NOx ≤ 200 mg/m³, efficiency ≥ 90%
Application to be submitted within 4 years from 31 December of the year of the invoice
Law of 24 July 2026: amounts published on guichet.public.lu (page updated on 11/08/2026)

Official source ↗