Klimabonus 551

Luft-Wasser-Wärmepumpe

What is Klimabonus 551?

Klimabonus 551 is a public subsidy scheme in Luxembourg supporting the installation of Luft-Wasser-Wärmepumpen in residential buildings.

An air-to-water heat pump uses energy from the ambient air to provide heating for the building. It is a renewable heating solution that helps reduce fossil fuel consumption and supports climate protection.

Technical requirements for air-to-water heat pumps

To be eligible for Klimabonus 551, the installation must meet the following technical requirements:

General technical requirements

Hydraulic balancing must be carried out after installation.
Installation of:
- eine separate or integrated electricity meter for the heat pump,
- eine separate or integrated heat meter for the heat pump.

Additional requirements for existing buildings

Installation of a buffer tank (boiler) with a minimum capacity of
30 litres per kWth of heating power.
This requirement does not apply to heat pumps equipped with a frequency converter (inverter) allowing speed or power modulation.

Performance requirements

The heat pump must meet the following coefficient of performance (COP) requirements in accordance with EN 14511:
- Air-to-water heat pump (including exhaust air heat pumps):
  COP ≥ 3.1 at A7/W35

Noise level requirements

- Der sound power level (Lw) of the external unit must comply with the following limits (according to the ErP label):
  - ≤ 5 kW: max. 48 dB(A)
  - > 5 kW and ≤ 12 kW: max. 51 dB(A)
  - > 12 kW: max. 55 dB(A)
  If the external unit exceeds these limits, the measured value may be reduced by installing additional soundproofing or noise protection equipment.
  Alternatively, if the sound power limits are not met:
  - the noise level at the boundary of the nearest building land must not exceed 40 dB(A),
  - compliance must be proven by an acoustic assessment based on a calculation tool provided by the Ministry,
  - this assessment must be carried out before installation.

Requirements for new buildings

For new buildings:

the heating system must be designed to supply the heating circuit with a maximum flow temperature of 35°C (W35).
If this is not possible, the heat pump must still achieve COP ≥ 3.1 at the selected operating temperature.

Hybrid systems

Für non-fossil hybrid systems:

at least 70% of the annual heat demand must be covered by the heat pump.

Conditions for receiving the subsidy

To receive Klimabonus 551, the following conditions apply:
- The subsidy is available only for heating systems in residential buildings.
- Only one heating system can be subsidised per residential building:
  - heat pump, oder
  - wood heating system, oder
  - connection to district heating.
- No state subsidy must have been requested for a technical installation under the 2016 or 2022 subsidy programmes.
- In the case of a hybrid system, the heat pump must cover at least 70% of the annual heat demand.

How to apply for Klimabonus 551

Der Beantragung der Förderung ist nach Abschluss der Installation möglich.

Klimabonus – sozialer Zusatzbonus

Förderfähige Haushalte können einen sozialen Zusatzbonus beantragen , nachdem sie den Bewilligungsbescheid für die Klimabonus-Förderung erhalten haben.

Applications must be submitted to:

Zentrale Anlaufstelle für Wohnungshilfe
11, rue de Hollerich
L-1741 Luxemburg
Großherzogtum Luxemburg
📧 guichet@ml.etat.lu
📞 (+352) 8002 10 10

Erforderliche Antragsformulare

Klimabonus – Basisförderung

“Demande d’une aide dans le cadre du paquet banque climatique et logement durable – DEPA-2026 – Personne physique”
(oder das Formular für Personnes morales)
“Chaudière à bois – Fiche BOIS 2026”
Or submission online via www.myguichet.lu
(only for private individuals and single-family homes)

Klimabonus – sozialer Zusatzbonus

“Demande en obtention d’une aide à l’assainissement énergétique (F3)”
“Déclaration relative à la composition de la communauté domestique (L/A21)”
“Déclaration sur l’honneur – Acquisition (A92)”

Validity of the Klimabonus 551 scheme

The Klimabonus 551 basic subsidy applies to:

Rechnungen mit Ausstellungsdatum zwischen dem 1 January 2026 and 31 December 2030,
subject to the finalisation of the legislative process for draft bill No. 8585.

Die auf dieser Seite beschriebenen Förderregeln beruhen auf dem offiziellen Rahmen der Klima Agence.
Da sich die Vorschriften ändern können, ist Klima Agence weiterhin die maßgebliche Stelle für die abschließende Prüfung.
Wir orientieren uns an ihren neuesten Leitlinien, damit unsere Kunden während des gesamten Prozesses korrekte und zuverlässige Informationen erhalten.

Our experts help you assess whether an air-to-water heat pump is suitable for your home, explain the technical requirements in clear terms, and guide you through the Klimabonus 551 subsidy conditions. Get practical advice, clear answers and support with the next steps free of charge and without obligation.

FAQ – Häufig gestellte Fragen

What does Klimabonus 551 support?

Klimabonus 551 supports the installation of air-to-water heat pumps in residential buildings, using renewable energy from the ambient air to provide heating.

Who can apply for Klimabonus 551?

The subsidy is available only for residential buildings, provided all technical and administrative requirements are met.

What technical requirements must the heat pump meet?

The installation must include: hydraulic balancing after installation, a separate or integrated electricity meter, a separate or integrated heat meter. Additional requirements may apply depending on the building type.

Is a buffer tank required?

Yes, for existing buildings, a buffer tank of at least 30 litres per kWth of heating power is required. This does not apply to inverter heat pumps with speed or power modulation.

What performance level is required?

The heat pump must achieve a Coefficient of Performance (COP) of at least 3.1 at A7/W35, in accordance with the EN 14511 standard.

Are there noise level requirements?

Yes. The outdoor unit must comply with defined sound power limits depending on system size. If these limits are exceeded, additional soundproofing may be used, or an acoustic assessment must demonstrate that noise levels at the nearest property boundary do not exceed 40 dB(A).

Are different rules applied for new buildings?

Yes. For new buildings, the heating system must be designed to operate with a maximum flow temperature of 35°C (W35). If this is not possible, the heat pump must still achieve the required COP value at the chosen operating temperature.

Are hybrid heating systems eligible?

Yes, provided the system is non-fossil and the heat pump covers at least 70% of the annual heat demand.

Can I receive multiple heating subsidies for one building?

No. Only one heating system can be subsidised per residential building: heat pump, or wood heating system, or connection to district heating.

Wann kann ich die Förderung beantragen?

The subsidy application can be submitted after the heat pump installation has been completed.

Is a social top-up subsidy available?

Yes. Eligible households may apply for a Social Top-Up Klimabonus after receiving the decision granting the basic subsidy.

Wer trifft die endgültige Entscheidung über die Förderung?

Final eligibility and approval are determined by the competent public authority, in accordance with the applicable legislation.

How long is Klimabonus 551 valid?

The Klimabonus 551 basic subsidy applies to invoices dated between 1 January 2026 and 31 December 2030, subject to the final adoption of draft bill No. 8585.