Energy renovation in Luxembourg: the complete A-to-Z steps and procedures for receiving the Klimabonus
How do you launch an energy renovation in Luxembourg? In what order should works be carried out? What administrative procedures are mandatory before, during and after the project to receive Klimabonus grants? This guide accompanies you at every stage of the process — from the first free consultation at the Klima-Agence to the payment of subsidies into your account — helping you avoid the pitfalls that cost homeowners thousands of euros in lost grants.
⚡ The essentials in 30 seconds
In Luxembourg, every Klimabonus 2026 grant application requires an agreement in principle obtained before works begin. Without this agreement, no subsidy can be paid — regardless of the quality of the works carried out. The procedure is submitted on MyGuichet.lu via the DEPA-2026 form. For a renovation covering several elements, an energy advisory by a Klima-Agence certified advisor is mandatory.
The 2 Klimabonus 2026 pathways — which is yours?
Since 1 January 2026, the Klimabonus Wunnen scheme offers two procedures depending on the scope of your project. Choosing the right pathway determines the steps to follow and the grants you can claim. This distinction is fundamental and deserves to be well understood before starting anything.
| Pathway A — multi-element renovation | Pathway B — single-element renovation | |
|---|---|---|
| When to use it? | You are renovating several elements (e.g. insulation + windows + heat pump) | You are renovating only one thermal envelope element (e.g. only the windows OR only the roof insulation) |
| Energy advisory | Mandatory — by a Klima-Agence certified advisor | Optional — but strongly recommended (+€500 grant if carried out) |
| Form to submit | DEPA-2026 + energy advisory report | DEPA-2026 + DESC sheet |
| Energy advisory grant | Up to €1,500 reimbursed | €400 for occasional advisory + €100 for compliance verification |
| Grant ceiling | 62.5% of eligible costs | 62.5% of eligible costs (flat-rate grant) |
| Technical installations | Included (heat pump, biomass boiler, PV, MVHR…) | Can be added separately via the « technical installations » section |
⚠️ Important
If you are planning multiple works on your home in due course, it is always more advantageous to choose Pathway A from the outset. Carrying out works in two separate stages without overall planning can cause you to miss grant synergies and force you to restart administrative procedures from the beginning. Consult our page on improving your energy class for an overview of the most impactful works.
Pathway A — multi-element renovation, step by step
This is the recommended pathway for any global or partial renovation involving several items. It guarantees the most significant grants and a coherent approach to your energy project.
Online simulation and pre-assessment
Before contacting any professional, use the Klima-Agence official simulator (aides.klima-agence.lu) to obtain a first estimate of available grants for your home. This step is free, anonymous, and lets you arrive prepared for the energy advisory.
Duration: 10 to 15 minutes. Cost: Free.
Free basic consultation at the Klima-Agence
Make an appointment with a Klima-Agence advisor for a free basic consultation. This can be done at home, by phone or video call. The advisor carries out an energy diagnosis, identifies priority works and informs you of all available grants. This first consultation is completely free, funded by the Klima-Agence and your municipality.
Contact: klima-agence.lu/fr/conseil or free hotline 8002 11 90 (Monday–Friday, 8am–12pm and 1pm–5pm). Service available in French, Luxembourgish, German and English.
Duration: 1 to 2 hours. Cost: Free.
In-depth energy advisory with report (mandatory for Pathway A)
For a multi-element renovation, you must commission a full energy advisory with report from a Klima-Agence certified advisor. This report forms the centrepiece of your agreement in principle file. The advisory invoice must be dated between 1 January 2026 and 31 December 2030. The Klimabonus grant for the energy advisory can reach €1,500 and is reimbursed after works.
Duration: 2 to 4 weeks. Indicative cost: €800 to €2,000 gross (reimbursed up to €1,500).
Obtaining certified quotes and comparison
Based on the energy advisory report, request at least 3 quotes per work item from tradespeople registered with the Luxembourg Chamber of Skilled Trades. Only works carried out by accredited companies are subsidised. Quotes must be sufficiently detailed — description of works, surfaces, materials with certified thermal performance (U or R value), amounts excl. and incl. VAT.
Duration: 2 to 6 weeks. Cost: Free (non-binding quotes).
Agreement in principle application — DEPA-2026 form ⚠️ Critical step
This is the most important step in the pathway. Before starting works, you must submit an agreement in principle application via MyGuichet.lu (DEPA-2026 form). This application must be validated before any work starts and before any quote is signed. Documents to provide include the signed DEPA-2026 form, the energy advisory report, contractor quotes, proof of building age (over 10 years) and material technical data sheets. The first application must be submitted between 1 January 2026 and 31 December 2030.
Processing time: 4 to 8 weeks. Cost: Free.
Parallel applications: Enoprimes and municipal grants
In parallel with the Klimabonus application, submit your Enoprimes application to Enovos or SUDenergie (enoprimes.lu). This also requires prior agreement before signing the quote — not just before works begin. Also check with your municipal administration for possible municipal grants.
Duration: 1 to 3 weeks. Cost: Free.
Municipal building permit (if applicable)
Depending on the nature of the works, a works declaration or building permit may be required — systematically for ETI modifying the facade appearance, roof modification, or geothermal heat pump installation requiring ground drilling. Check with your municipal planning department before starting.
Duration: 2 to 8 weeks. Cost: Variable.
Carrying out works — in the correct order
Once the agreement in principle is obtained and quotes are signed, works can begin. Sequencing is fundamental: start with the envelope (roof insulation, then walls, then windows) before installing or replacing the heating system. A heat pump installed before insulation will be oversized afterwards. During works, keep all material delivery notes and request a works completion certificate from each tradesperson.
Duration: 2 to 6 months. Allow 2 to 8 months for tradesperson lead times.
Post-works energy passport (if required)
After works, an updated energy passport must be established by an accredited expert for certain significant works on the thermal envelope (regulatory obligation from the Grand Ducal Regulation of 9 June 2021). This document enhances your property value and may be required for the Klimabonus payment application.
Duration: 1 to 2 weeks. Cost: €400 to €800.
Payment application — receiving Klimabonus grants
After receiving final paid invoices, submit the grant payment application via MyGuichet.lu (DEPA-2026 form — payment section). This file must be submitted within 4 years of 31 December of the invoicing calendar year. Grants are transferred directly to your bank account.
Processing time: 4 to 12 weeks. Cost: Free.
Simulate your Klimabonus grants in a few minutes before launching your procedures.
Simulate my grants →Pathway B — single-element renovation (simplified procedure)
If you only wish to renovate one thermal envelope element, you can use the simplified procedure without a mandatory energy advisory. This procedure is faster but grants are strictly limited to the item concerned.
Elements eligible under the simplified procedure (one at a time): external wall insulation, roof or loft insulation, floor insulation, replacement of windows and external doors.
Obtain a quote from a certified tradesperson
Have a quote drawn up by a company registered with the Luxembourg Chamber of Skilled Trades. The quote must state the materials used and their thermal performance (R-value in m².K/W or U-value in W/m²K). A tradesperson holding the « Klima-Agence certified Artisan » label can handle the administrative procedures directly for individual measures.
Complete the DESC sheet and submit DEPA-2026
Complete the annex sheet « Description of the measure for the construction element » (DESC). This sheet must be signed by you and the tradesperson. Submit the DEPA-2026 form with the DESC sheet on MyGuichet.lu. Include proof of building age (over 10 years) and the cost estimate or quote. This step must be completed before works begin.
Carry out works after the agreement in principle
Only start works after receiving the official agreement in principle notification. Keep all documents: material delivery notes, signed installation certificate, ten-year and satisfactory completion guarantees.
Payment application after invoicing
Submit your payment application with paid invoices and proof of payment within 4 years of 31 December of the invoicing year. Payment is made directly to your bank account within 4 to 12 weeks.
💡 Tip
Even under the simplified procedure, calling on an energy advisor to verify quote compliance earns you an additional €500 grant (€400 for occasional advisory + €100 for compliance verification).
In what order should works be carried out?
The sequence of works is a crucial technical point, often overlooked. A poor sequence can lead to energy inefficiencies, an oversized heating system or thermal bridges that insulation can no longer correct afterwards.
Priority 1 — roof and loft insulation
The roof accounts for 25 to 30% of heat losses. It offers the best return on investment (4 to 8 years for unoccupied lofts). Starting with the roof allows correct sizing of subsequent steps and immediately reduces the heating bill. See our complete guide on roof and loft insulation.
Priority 2 — external wall insulation (ETI)
Walls account for 20 to 25% of losses. External thermal insulation (ETI) is preferred as it eliminates structural thermal bridges and preserves interior living space. It must be carried out after the roof to ensure insulation continuity at the roof/wall junction. Where ETI is impossible, internal insulation (ITI) is the alternative.
Priority 3 — window and door replacement
Windows account for 10 to 20% of losses. They must be replaced after ETI to ensure insulation continuity with the new facade reveal and avoid thermal bridges around the frames. See our comparison of double vs triple glazing.
Priority 4 — heating system (heat pump)
The heating system must be sized after insulation to match the actual needs of the renovated building. A heat pump installed before insulation will be oversized — it consumes more electricity, degrades faster from excessive cycling, and its actual COP is lower than the nominal COP. A serious Luxembourg heating installer will refuse to size the heat pump before knowing the building’s final thermal performance.
Priority 5 — MVHR (heat recovery ventilation)
In a well-insulated and airtight home, natural air renewal becomes insufficient. MVHR must be installed after insulation and airtightness works, but before interior finishes to allow duct routing. See our complete guide on MVHR in Luxembourg.
Priority 6 — photovoltaic panels and battery
PV panels can technically be installed at any stage, but it is advisable to install them last to account for the actual electricity consumption of the renovated home — particularly with the heat pump. This allows optimal sizing of the installation. The Klimabonus pre-financing available since 4 January 2026 considerably simplifies the financial process.
Assembling the administrative file — required documents
To avoid back-and-forth with the single housing grants window, here is the complete list of documents to prepare according to the chosen procedure. An incomplete file is the most common cause of additional delay.
| Document | Pathway A (multi-element) | Pathway B (simplified single-element) | Where to obtain it |
|---|---|---|---|
| DEPA-2026 individual person form | ✓ Mandatory | ✓ Mandatory | MyGuichet.lu |
| Energy advisory report | ✓ Mandatory | ✗ Not required (unless +€500 grant sought) | Klima-Agence certified advisor |
| DESC sheet (measure description) | ✓ For each envelope element | ✓ Mandatory | MyGuichet.lu — to complete with tradesperson |
| Quote or cost estimate | ✓ Mandatory | ✓ Mandatory | Tradesperson registered with Chamber of Skilled Trades |
| Original building permit (proof of age >10 years) | ✓ Mandatory | ✓ Mandatory | Municipality, cadastral archives or notarial deed |
| Construction plans (if extension) | If applicable | If applicable | Architect or municipality |
| COLL-2026 sheet (co-ownerships) | If co-ownership | If co-ownership | MyGuichet.lu |
| PROC-2026 proxy for each co-owner | If co-ownership | If co-ownership | MyGuichet.lu |
| For the payment application (after works): | |||
| Detailed paid invoices | ✓ Mandatory | ✓ Mandatory | Tradesperson |
| Invoice payment proof | ✓ Mandatory | ✓ Mandatory | Bank statement or payment receipt |
| Bank account details (IBAN) | ✓ Mandatory | ✓ Mandatory | Your bank |
⚠️ Proof of building age
If you cannot find the original building permit, other official documents may be accepted: notarial purchase deed mentioning the construction date, municipal certificate, cadastral extract or land register extract. As a last resort, an expert can certify the building’s age based on a technical inspection.
Submitting your application on MyGuichet.lu — step-by-step guide
The MyGuichet.lu platform is the official portal of the Luxembourg administration for all online procedures, including Klimabonus applications.
Create or activate your MyGuichet account
Go to myguichet.lu. Login is via LuxTrust (token or card), the Luxembourg government mobile app, or eID. If you do not yet have a LuxTrust account, allow 1 to 2 weeks to obtain one. For foreign residents, login via eIDAS (European electronic identity card) is also accepted.
Access the DEPA-2026 form
In the « Housing grants » section of MyGuichet.lu, select « Klimabonus Wunnen 2026« , then choose the appropriate procedure. The DEPA-2026 form is entirely online and can be completed in multiple sessions — save your entry at any time.
Upload supporting documents
Scan all required documents in PDF or JPG format. Clearly name your files (e.g. « QUOTE_roof_insulation_tradeX.pdf »). Scan quality must allow unambiguous reading.
Submit and keep the receipt
After submission, you receive an electronic receipt with a case number. Keep this receipt: it proves the submission date. Paper submission is also possible at the single grants window or by registered post with acknowledgement of receipt.
Case tracking and receipt of agreement in principle
Your case progress is viewable at any time on MyGuichet.lu. The agreement in principle is notified officially within a typical 4 to 8 weeks. Wait for this written confirmation before starting works — not before, and not on the very day of receiving the notification.
Official Klimabonus 2026 calendar and deadlines
The 2026 Klimabonus scheme offers a long time window, but several key deadlines must be strictly respected to avoid losing all or part of the grants. These are limitation deadlines — they cannot be extended after expiry.
| Event / Deadline | Deadline date | Note |
|---|---|---|
| First agreement in principle application (DEPA-2026) | 31 December 2030 | Must be submitted before any work begins and before any quote is signed |
| Eligible invoices (works carried out) | 1 Jan. 2026 → 31 Dec. 2035 | Invoices issued before 1 Jan. 2026 may fall under the 2022 scheme |
| Energy advisory invoice | 31 December 2030 | Must be issued within the eligibility period to be reimbursed |
| Payment application (liquidation) | 4 years after 31 Dec. of the invoicing year | 2026 invoices → file before 31 Dec. 2030. Absolute limitation deadline. |
| Absolute payment deadline | 31 December 2039 | No application accepted after this date under any circumstances |
| Agreement in principle — processing time (indicative) | 4 to 8 weeks | Variable depending on AEV administrative workload |
| Grant payment after application (indicative) | 4 to 12 weeks | Direct bank transfer — extended during high-demand periods |
ℹ️ PV pre-financing (since 4 January 2026)
For photovoltaic installations only, the pre-financing mechanism allows an officially registered installer to deduct the Klimabonus subsidy directly from the final invoice. You therefore pay the net amount immediately — without advancing the subsidy amount and without waiting for the state to pay. The extension of this mechanism to other work items is planned for a later phase.
Combining with Enoprimes
Enoprimes are complementary grants offered by Luxembourg distribution network managers (Creos and Sudstroum/Enovos). They are stackable with the Klimabonus and provide up to €10–15/m² more on thermal insulation and additional grants for technical equipment.
Check your eligibility on enoprimes.lu
Visit enoprimes.lu. Contrary to common belief, you do not need to be an Enovos or SUDenergie customer to benefit from Enoprimes — they are accessible to all Luxembourg residents whose home is connected to the Luxembourg distribution network.
Request Enoprimes prior agreement BEFORE works AND before signing the quote
Enoprimes require prior agreement before signing the quote — not just before works begin. This rule is stricter than the Klimabonus. Submit your application on enoprimes.lu with your tradesperson’s unsigned quote. The application is typically processed within 1 to 2 weeks.
Send invoices after works for payment
After works are completed, submit paid invoices and proof of payment on enoprimes.lu. Payment typically occurs within 4 to 8 weeks. Enoprimes management is entirely independent of the Klimabonus.
Combining with municipal grants
Many Luxembourg municipalities offer supplementary grants for energy renovation, generally expressed as a percentage of the Klimabonus received. The Klima-Agence simulator (aides.klima-agence.lu) automatically indicates the municipal amounts applicable to your situation.
| Municipality (examples) | Municipal grant (% of Klimabonus) | Indicative ceiling |
|---|---|---|
| Lintgen | 50% | ~€1,500 |
| Differdange | 40% | Variable |
| Bertrange | 25% | ~€1,800 |
| Rambrouch | up to 50% | Variable by item |
| Your municipality | → Check at aides.klima-agence.lu or directly with your municipal administration | |
💡 Procedure and timing
Municipal grants are generally applied for directly with your municipal administration after receiving the Klimabonus grants. Supporting documents typically required include the Klimabonus award notification, works invoices and proof of payment.
PV pre-financing — the 2026 major innovation
Since 4 January 2026, photovoltaic installations benefit from a pre-financing mechanism: the Klimabonus subsidy is deducted directly from the final invoice by the installer, without you needing to advance the subsidy amount and wait for state reimbursement.
Choose an installer registered in the official registry
To benefit from pre-financing, your installer must be registered in the registry of installers admitted to the pre-financing procedure, published by the Ministry of the Economy on guichet.public.lu. Check this registry before contacting any PV installer.
The installer submits the grant application
Under the pre-financing scheme, it is the installer who submits the financial aid application to the administration. They deduct the subsidy amount directly from your final invoice. You pay only the net amount after subsidy, upon completion of works.
Conditions to be met
The installation must have a minimum capacity of 2 kWp and maximum of 30 kWp (the maximum subsidy of €10,000 is reached at 15 kWp). It must operate in self-consumption mode and be connected to the grid. A domestic battery can be included in the pre-financing (max. subsidy €2,250 for 9 kWh capacity).
7 critical errors that cause grants to be lost
Starting works before the agreement in principle
This is error number one and it is irreversible. If works begin before the official agreement in principle notification, all Klimabonus grants are permanently lost for the elements concerned. No exceptions are provided for in the regulations, and no appeal is possible.
Having works carried out by a non-accredited company
Only tradespeople registered with the Luxembourg Chamber of Skilled Trades are eligible. A non-registered tradesperson, however skilled, does not give entitlement to any grant. Check the tradesperson’s registration number on each quote before approving it.
Forgetting to apply for Enoprimes BEFORE signing the quote
Enoprimes require prior agreement before signing the quote — not just before works begin. A homeowner who only applied for the Klimabonus permanently loses this supplementary grant. On a house, this can represent €1,000 to €3,000 lost.
Submitting the payment application too late
The 4-year deadline from 31 December of the invoicing year is a limitation deadline: after this deadline, the right to the grant is permanently lost. For 2026 invoices, the payment application must be submitted before 31 December 2030.
Not keeping proof of invoice payment
The single grants window requires detailed paid invoices accompanied by proof of payment. An invoice without corresponding proof of payment will not be accepted in the payment application file. Scrupulously keep all bank statements covering your works payments.
Carrying out several elements under the simplified procedure to circumvent the energy advisory requirement
The simplified procedure (Pathway B) only applies to a single thermal envelope element. As soon as you are working on two or more elements, Pathway A with energy advisory is mandatory.
Choosing a PV installer not registered in the pre-financing registry
To benefit from the pre-financing mechanism, the installer must be registered in the Ministry of the Economy’s official registry. An unregistered installer cannot offer pre-financing: you will need to advance the subsidy amount and wait for standard reimbursement.
Frequently asked questions about energy renovation procedures
How long does the whole process take from first step to grant payment?
For a complete project with energy advisory, allow 6 to 18 months in total: 1 to 2 months for the advisory and quotes, 4 to 8 weeks for the agreement in principle, 2 to 6 months for works (tradesperson lead times included), then 4 to 12 weeks for payment application processing. The earlier you begin administrative procedures, the better your cash flow will be preserved.
Can my tradesperson manage all the procedures on my behalf?
Some certified tradespeople offer full administrative support. This is a practical option, particularly for Pathway B. However, for Pathway A, the agreement in principle remains an official procedure in your name: you must authenticate on MyGuichet.lu with your personal LuxTrust to finalise and submit the DEPA-2026 form. Your tradesperson or advisor can prepare the file, but the final submission is yours.
Can I receive grants if I rent out my property?
Yes, subject to conditions. Landlords can apply for Klimabonus grants for renovation works on their Luxembourg rental property. Improving the energy class of a rental property is particularly relevant given discussions on rent regulation according to CPE class.
What if I no longer have the original building permit?
Other official documents proving the building’s age (over 10 years) may be accepted: notarial purchase deed mentioning the construction date, municipal certificate, cadastral extract or land register extract. If you encounter difficulties, contact your municipality or the National Archives. Check with the single grants window before blocking your file on this point.
Is the Klimabonus taxable?
No. For resident individuals, Klimabonus grants do not constitute taxable income and do not need to be declared in the Luxembourg tax return. For owners who deduct works for professional or rental purposes, consult a tax advisor — particularly regarding the accelerated depreciation of 6% over 10 years provided for landlords who have carried out a Klimabonus renovation.
What happens if works cost less than the approved quote?
The grant is calculated on actual costs stated on invoices, not on the estimated quote. If works cost less than expected, the grant will be proportionally reduced. If works cost more (unforeseen site issues), you can in some cases submit a modification request to the agreement in principle before exceeding the initial budget.
Is the Klima-Agence basic consultation different from the energy advisory with report?
Yes, these are two distinct services. The basic consultation is free, informal and produces no official report usable in a Klimabonus file. The energy advisory with report (paid, reimbursed up to €1,500) is a regulated service producing a formal report mandatory for Pathway A. If in doubt, start with the free basic consultation to assess the scope of your project.
What number should I call if I have questions about the procedures?
The Klima-Agence has a free hotline: 8002 11 90, available Monday to Friday from 8am to 12pm and 1pm to 5pm (excluding public holidays). The service operates in French, Luxembourgish, German and English.
Ready to launch your project? Start by estimating your grants
Use our simulator to precisely calculate the grants available for your renovation, then request quotes from Klima-Agence certified tradespeople. Our partners can support you through all Klimabonus administrative procedures.