Financial aid for energy efficiency renovation of a residential building based on an energy performance assessment (Klimabonus scheme 2026)
Last update
Important information: Continuation and partial reform of the 'Klimabonus Wunnen' financial aid scheme
You will be able to submit your application for the Klimabonus Wunnen 2026 financial aid scheme from 1 January 2026, the date on which the scheme is scheduled to take effect, with retroactive effect if the law has not been published before that date. However, because the law is still going through the legislative procedure, the processing and consideration of your application remain subject to the publication of the law in the Official Journal.
Summary:
You can apply for financial aid under the Klimabonus 2026 scheme subject to certain conditions.
The Environment Agency (Administration de l’environnement – AEV) grants subsidies for renovation projects undertaken to:
- improve the long-term sustainability of a residential building;
- implement technical installations making use of renewable energy sources.
The Klimabonus scheme applies to sustainable energy efficiency renovations of residential buildings older than 10 years from the date of issue of the building permit.
For energy performance assessments conducted before 31 December 2025, the former Klimabonus aid scheme (RGD 2022) applies, provided that the application for an agreement in principle was submitted by 31 December 2025.
You may receive Klimabonus aid only once per construction element, and only for a residential building located in Luxembourg.
Who is concerned
Applicants concerned
Anyone who wishes to improve the energy performance of their residential building – that is, any:
- natural person;
- legal person established under private law;
- public legal person other than the State.
You can submit your application in your capacity as:
- the legal representative of a group of natural or legal persons, provided that you are a part of this group yourself;
- the owner of the dwelling, except when there is a change of ownership and the new owner of the dwelling and/or technical installation forgoes the aid in question for the benefit of the former owner who made the investments.
Works concerned
You may apply for aid for:
- the insulation of roofing;
- the insulation of an external wall;
- the insulation of a ceiling slab in contact with an unheated attic;
- the insulation of the lower floor slab that adjoins an unheated basement or the floor, or the exterior;
- the insulation of a wall in contact with the ground or an unheated zone;
- the replacement of windows;
- centralised or decentralised controlled ventilation systems.
Prerequisites
Eligible buildings
The residential building must be older than 10 years from the date of issue of the building permit when the financial aid application is submitted.
The date of the building permit or the certificate issued by the communal administration constitute proof of the age of the building.
The energy performance assessment must be supplemented by occasional monitoring by the approved energy consultant during the energy efficiency renovation.
Technical requirements to be fulfilled
To be eligible for the subsidy:
- the renovated elements must not exceed certain heat transfer coefficients;
- the minimum thickness of the insulating material (performance standard III) must be complied with for all other performance standards.
No aid will be allocated for the surfaces of elements renovated with fossil-based insulation material, except for ground-supported walls, green roofs, green walls and floor slabs in contact with the ground. This provision does not apply to fossil-based insulation material made from more than 50% recycled materials. 'Fossil-based' (synthetic insulation) insulation materials for which more than 50% of the raw materials come from biomass are eligible under the category 'other materials'.
If the attic space is heated, the renovation of the roofing must be combined with the replacement of the roof windows if these windows are more than 10 years old and do not have a heat transfer coefficient lower than or equal to 1.40 W/m2K.
to prevent humidity due to condensation, and the ensuing problems (mould, etc.), the renovation of the windows may be subsidised, provided that:
- the external wall or the roof of the heated attic space has a heat transfer coefficient lower than or equal to 0.85 W/m2K; or
- the building has a controlled mechanical ventilation system.
If a controlled ventilation system with heat recovery is being installed:
- the yield of the heat recovery system must be greater than or equal to 80%;
- the absorbed electrical power may not exceed 0.40 W/(m3/h);
- the building must be airtight (n50 ≤ 2.01 hour), as established by an airtightness test;
- at least 80% of the energy reference area must be mechanically ventilated.
| Performance standard III | Performance standard II*** | Performance standard I*** | |
|---|---|---|---|
| Minimum thickness of insulation in cm | Maximum value of U (W/m2K) | Maximum value of U (W/m2K) | |
| External wall (external insulation) | 15 | 0.17 | 0.13 |
| External wall (internal insulation) or insulation of the interior side combined with insulation of the exterior side***** | 8* | 10 cm* | 12 cm* |
| Ground-supported wall or unheated zone | 12 | 0.22 | 0.17 |
| Pitched or flat roof**** | 20 | 0.13 | 0.11 |
| Ceiling slab against unheated zone | 20 | 0.13 | 0.10 |
| Floor slab in contact with an unheated zone, the ground or the exterior | 12 | 0.22 | 0.15 |
| Windows and French windows** | Ug ≤ 0.6 W/(m2K) |
The minimum thicknesses of the thermal insulation materials shown in the table above apply to a heat conductivity of 0.035 W/(mK) for the insulation material. For other heat conductivities, the minimum thicknesses should be converted based on the actual heat conductivity of the insulation material.
* The minimum thicknesses of the thermal insulation materials shown in the table above for external walls insulated on the interior side apply to a heat conductivity of 0.040 W/(mK) for the insulation material. For other heat conductivities, the minimum thicknesses should be converted based on the actual heat conductivity of the insulation material.
** Conditions for granting the aid:
- either guarantee a certain heat quality of the external wall based on the targeted performance standard (Uwall ≤ 0.85 W/m2K);
- or install a controlled mechanical ventilation system.
*** The minimum thickness of the insulation material (performance standard III) must be complied with for all other performance standards.
**** If the attic space is heated, the renovation of the roof must include the replacement of the roof windows (if they are more than 10 years old, and if UW > 1.4 W/m2K) The new window must have a UW ≤ 1.4 W/m2K.
***** If both the interior and exterior sides are insulated, the insulation material applied on the exterior side must have a thermal resistance R of at least 2 (m2K)/W.
It should be noted that the minimum energy performance requirements also apply to residential buildings that are protected in the public interest, and are either fully or partially listed as national monuments.
Energy performance assessment
To receive the Klimabonus aid for the sustainable energy renovation of an existing building, you must first have an energy performance assessment carried out and obtain the related report. The assessment and report must be produced by an approved energy consultant to ensure that the energy efficiency renovation project is of suitable quality before the works begin.
The invoice for this consultancy service must be issued between 1 January 2026 and 31 December 2030 inclusive.
The report drawn up in connection with the energy assessment contains recommendations on how to improve the home's energy performance. Financial aid may also be granted for this consultancy service.
Financial aid for an energy assessment by an approved energy consultant
The amount of financial aid granted for a sustainable energy renovation project is:
- EUR 1,700 for a single-family residence (a house);
- EUR 2,000 for a residence comprising 2 flats. A EUR 60 supplement is added to this base amount for each additional flat. The total amount of aid is capped at EUR 3,000.
The amount of the financial aid can never exceed the actual cost of the energy consultation.
The financial aid for an energy performance assessment is reduced by:
- 50% if the same element is eligible for financial aid for the energy performance assessment under the 2017 financial aid scheme or the 2022 financial aid scheme;
- 70% if the energy performance assessment only covers the following technical installations:
- solar thermal systems;
- heat pumps;
- wood-fuelled boilers;
- installation of a heat network and/or connections to the heat network.
If the energy performance assessment was conducted in connection with a sustainable energy renovation project, the financial aid may be increased by EUR 160 (EUR 800 maximum) for the calculation of a thermal bridge and proposals for related treatments if:
- the renovation works have been implemented;
- the heating energy expenditure index of the building, after the works, reaches at least efficiency class C.
The energy performance assessment must be supplemented by occasional monitoring by the energy consultant, which can be covered by financial aid in the case of:
- measures taken to confirm the conformity of estimates provided for the works (EUR 100 per measure, capped at EUR 400);
- measures taken to confirm the conformity of the works on-site (EUR 250 per measure, capped at EUR 1,000).
Prior to commencing the energy efficiency renovation works, you must obtain an agreement in principle from the Single point of contact for housing assistance (Guichet unique des aides au logement), established on the basis of an energy consultant's report.
Deadlines
Applications for financial aid must be filed with the Single point of contact for housing assistance after the end of the works and no later than 4 years after 31 December of the calendar year to which the invoice pertains.
The invoices for the energy efficiency renovation works must be issued between 1 January 2026 and 31 December 2035 inclusive.
The first application for an agreement in principle must be submitted between 1 January 2026 and 31 December 2030 inclusive.
The invoice for the energy performance assessment must be issued between 1 January 2026 and 31 December 2030 inclusive.
Applications for financial aid for liquidation must be submitted no later than 31 December 2039.
How to proceed
You must file your application with the Single point of contact for housing assistance (Guichet unique des aides au logement).
- Prior to the works: application for the agreement in principle
- After the works: request for payment of the aid
Prior to commencing the energy efficiency renovation works, you must obtain an agreement in principle from the Single point of contact for housing assistance, established on the basis of an energy consultant's report.
To obtain an agreement in principle, you must submit your request:
- either online via MyGuichet.lu or the MyGuichet.lu mobile application (see 'Online services and forms' below). This is a procedure with authentication that requires:
- a LuxTrust product; or
- an electronic identity card (eID);
- or by post (preferably by registered mail), or by submitting the dedicated form (see 'Online services and forms') directly at the Single point of contact for housing assistance (Guichet unique des aides au logement):
- if you are a natural person: the DEPA-2026 aid application form for natural persons; or
- if you represent a legal person: the DEPA-2026 financial aid application form for legal persons.
The form must be accompanied by all the required supporting documents.
Once the agreement in principle has been obtained, you can begin the renovation works.
Note: If, based on the advice of the energy consultant, you change your renovation concept after obtaining the agreement in principle, you can file an application to obtain a new agreement in principle.
Once the energy efficiency renovation works have been completed, you can apply for the payment of the financial aid for energy efficiency renovation. To do this, you must use the form 'Confirmation of energy efficiency renovation of an existing residential building' (Confirmation rénovation énergétique d’un logement existant – CONF-2026) that has been provided by the approved energy consultant.
This form must be accompanied by supporting documents.
Supporting documents
- Application for the agreement in principle
- Application for payment of financial aid
For the application for the agreement in principle, in addition to the DEPA-2026 financial aid application form (natural or legal person), you must provide:
- the appendix form entitled 'Energy efficiency renovation concept' (Concept d’assainissement énergétique – COAS_2026), specifying all the projected energy efficiency renovation measures subject to the agreement in principle. It must be completed and signed by the approved energy consultant;
- a bank account identification document (RIB) for the account indicated in the application form;
- upon the AEV's request, the concluding report prepared by the energy consultant, including the overall inventory and the entire energy efficiency renovation concept;
- a copy of the initial building permit for the building or an official document certifying the age of the building;
- the energy performance certificate (certificat de performance énergétique – CPE) of the building before the renovation works;
- if a controlled mechanical ventilation system is being installed, construction plans that:
- correspond to the situation after the energy efficiency renovation works; and
- illustrate the energy reference area and the mechanically ventilated portion of this area;
- in the case of an extension or enlargement of the building's thermal envelope, building plans corresponding to the situation after the energy efficiency renovation works;
- an estimate of the energy consultant's fees or a confirmed estimate per projected measure;
- If the application is for a commonhold property or a multi-unit residence:
- the appendix form COLL-2026 and a power of attorney for each owner PROC-2026. Alternatively, a report drawn up by the commonhold association during a general meeting authorising the renovation works;
- the list of the flats, specifying the energy reference area per flat, excluding the common areas.
With respect to the application for the payment of aid, in addition to the form titled 'Confirmation of energy efficiency renovation of an existing residential building' (Confirmation rénovation énergétique d’un logement existant – CONF-2026), applicants must provide:
- if you are a private individual: the DEPA-2026 aid application form for natural persons;
- if you represent a legal person: the DEPA-2026 financial aid application form for legal persons;
- where applicable, the form reporting any change of address or bank account details;
- a recent bank account identification document (RIB) that indicates the account listed on the application form or the form reporting any change of address or bank account details;
- copies of invoices that prove the eligible costs and proof of payment (notice of debit or invoice receipted in due and proper form). The invoices may refer to a detailed estimate, in which case this estimate must be attached to the invoice. The invoices for the energy consultation must be detailed as follows:
- the energy consultation provided;
- confirmation of the conformity of the estimates;
- on-site confirmation of the conformity of the works;
- any thermal bridge calculations, if applicable;
- the final report prepared by the energy consultant upon confirmation of the conformity of the estimates and on-site confirmation of the conformity of the works;
- the energy performance certificate (certificat de performance énergétique – CPE) of the building after the renovation works;
- if a controlled mechanical ventilation system with heat recovery is installed, the duly signed airtightness assessment reports and certificate;
- if the application pertains to a commonhold or multi-unit residence (if any amendments have been made to the first application):
- the appendix form COLL-2026 and a power of attorney for each owner PROC-2026. Alternatively, a report drawn up by the commonhold association during a general meeting authorising the renovation works;
- the list of the flats, specifying the energy reference area per flat, excluding the common areas.
The Single point of contact for housing assistance may ask you to provide any documents it deems necessary to process the file.
Amount of subsidies
Basic subsidy
The amounts are calculated based on the surface areas of the renovated elements. The area of the renovated element is multiplied by the corresponding amount shown in the table below.
| Refurbished construction element of the thermal envelope | Category of insulation material | Performance standard III | Performance standard II | Performance standard I |
|---|---|---|---|---|
| Element in contact with the exterior: external wall (insulated on the exterior side, on the interior side in combination with insulation on the exterior side, or insulated only on the interior side***), pitched or flat roof, floor slab in contact with the exterior | a. fossil-based (minimum 50% recycled)* and other materials** | 35 | 45 | 60 |
| b. mineral | 60 | 70 | 85 | |
| c. eco-friendly | 90 | 100 | 115 | |
| External wall (insulated on the exterior side) with cladding**** | c. eco-friendly | 105 | 115 | 130 |
| Element in contact with an unheated zone or the ground: ceiling slab in contact with an unheated zone, wall or floor slab in contact with the ground or an unheated zone | a. fossil-based (minimum 50% recycled)* and other materials** | 20 | 30 | 45 |
| b. mineral | 25 | 35 | 50 | |
| c. eco-friendly | 40 | 50 | 65 | |
| Windows and French windows | 70 |
* recycled fossil-based insulation material required except for walls in contact with the ground, green roofs, green walls and slabs in contact with the ground;
** other materials: materials that do not fall under the definitions of categories (b) and (c) and that are not fossil based;
*** for insulation that is only on the interior side, the specific financial aid [euros/m2 renovated] listed in the table above is reduced by 25%;
**** eco-friendly insulation material and cladding must be attached mechanically; cladding that contains fossil-based materials is not permitted.
The requirement of mechanical attachment for category (c) eco-friendly insulation materials does not apply to walls insulated from the inside or outside.
Aid mark-up for the use of recycled materials for mineral insulation material
If mineral insulation materials made from at least 50% recycled materials are used, a EUR 15 mark-up on the base subsidy is granted.
Aid mark-up for the use of eco-friendly insulation materials whose components are sourced from certified sustainable crops
If eco-friendly insulation materials whose components are sourced from certified sustainable crops are used, a EUR 15 mark-up on the base subsidy is granted.
Aid mark-up for laying exterior green spaces
If the renovation project involves installing a green roof or a green external wall, a EUR 15 mark-up on the base subsidy is granted.
Energy class bonus
If the building meets thermal insulation classes C, B, A or A+ after renovation, the amount of the subsidy granted for the individual measures implemented on the thermal envelope may be increased, provided that the thermal insulation class has improved by at least 2 grades.
To receive the bonus, the insulation measures may also be implemented in stages.
| Thermal insulation class after renovation | Bonus on the amount of the subsidy granted for measures implemented on the thermal envelope |
|---|---|
| C | 20% |
| B | 30% |
| A or A+ | 50% |
Proof of eligibility for the bonus must be demonstrated by producing the energy performance certificates before and after the energy efficiency renovation works.
Measures implemented and subsidised under the former aid schemes may be taken into account to demonstrate the improvement by at least 2 classes, which is required for eligibility for the aid bonus.
Controlled mechanical ventilation system
The financial aid is calculated based on the energy reference area.
The energy reference area is multiplied by the corresponding amount shown in the table below.
| Single-family house | Dwelling in a multi-unit building | |
|---|---|---|
| Ventilation with heat recovery | 60 | 60 |
Payment of financial aid
The aid is generally transferred directly to your bank account.
If you are acting in your capacity as a legal representative of a group of natural or legal persons, the aid is transferred directly to your bank account and you must immediately credit the bank accounts of the natural or legal persons concerned with their respective share of the aid.
A copy of these payments must be sent to the Single point of contact for housing assistance.
Repayment of aid
If you have already received the aid, you may be required to return it, if:
- you are found to have made inaccurate or incomplete statements in order to obtain the aid; or
- you fail to provide the Single point of contact for housing assistance with the requested declaration, information or documents.
Good to know
Some communes grant supplementary aid on top of state aid for energy savings and renewable energies. For more information, please contact your commune of residence or Klima-Agence.
Online services and forms
Online services
Downloadable forms
Note: view tips for using PDF forms.
Applications and attachments (to be filled in by the applicant)
Certificates of conformity (to be filled in by the professionals)
Change of address and/or bank account
Who to contact
Klima-Agence
- Address:
- 2, circuit de la Foire Internationale L-1347 Luxembourg Luxembourg
- Phone:
- (+352) 8002 11 90
- Email address:
- info@klima-agence.lu
- Website:
- http://www.klima-agence.lu
Ministry of Housing and Spatial Planning Single point of contact for housing assistance
- Address:
- 11, rue de Hollerich L-1741 Luxembourg Luxembourg
- Phone:
-
(+352) 80 02 10 10
Monday to Friday from 8.00 to 16.00
- Fax:
- (+352) 45 88 44
- Email address:
- info@ml.etat.lu
- Website:
- http://www.logement.lu
Closed ⋅ Opens Monday at 8.00
- Friday:
- 8.00 to 12.00 , 13.30 to 16.00
- Saturday:
- Closed
- Sunday:
- Closed
- Monday:
- 8.00 to 12.00 , 13.30 to 16.00
- Tuesday:
- 8.00 to 12.00 , 13.30 to 16.00
- Wednesday:
- 8.00 to 12.00 , 13.30 to 16.00
- Thursday:
- Closed
Related procedures and links
Procedures
Links
Legal references
-
Commission Regulation (EU) 2023/2831 of 13 December 2023
on the application of Articles 107 and 108 of the Treaty on the Functioning of the European Union to de minimis aid
-
Projet de loi 8585
instituant un régime d’aides pour la promotion de la durabilité, de l’utilisation rationnelle de l’énergie et des énergies renouvelables dans le domaine du logement
