How can you finance a solar PV system in Luxembourg: Klimabonus pre-financing, loan or leasing?
By Yacine Sahnoune, founder of renov.lu
In Luxembourg, pre-financing of the solar PV Klimabonus means you never advance the grant: an installer listed in the register deducts it from your invoice, and the deposit is capped at 30%. For 6 kWp at €12,000 including VAT, you pay at most €3,600 when ordering and €2,658 at the end. The rest can be financed with a Klimaprêt, on which the State pays 1.5% of interest a year.
- Pre-financing: available for solar PV since January 2026, for the same grant amount as the standard procedure
- Deposit: at most 30% of the price incl. VAT; grant deducted from the invoice incl. VAT
- Timeframes: decision within 15 working days (no reply means approval), installer paid within the next 15 working days
- Excluded: a battery added on its own, leased systems, commercial companies
- Dates: order signed by 31 December 2029, application by 31 December 2031
- Klimaprêt: 1.5% of interest a year paid by the State, on up to €100,000 and 15 years, with no income condition
- Heat pumps and insulation: pre-financing only for invoices issued from 1 January 2027
Installers who pre-finance the grant
Ask installers established in Luxembourg for quotes: each offer states the grant deducted and the deposit requested.
Solar Klimabonus pre-financing in brief
Pre-financing is optional: instead of paying for the whole system and then waiting for the grant, you let the installer deduct the Klimabonus from the invoice and apply for the grant from the State. The amount is the same as in the standard procedure: €5,742 for 6 kWp, €10,000 from 15 kWp.
- Legal basis: law of 19 December 2025 introducing a pre-financing procedure for solar PV systems (parliamentary doc. 8463), managed by the Ministry of the Economy. On 1 January 2027 the scheme is incorporated into the Klimabonus Wunnen law of 24 July 2026.
- What it covers: the solar PV system and a battery bought at the same time.
- For other works: pre-financing of heat pumps and insulation will only apply to invoices issued from 1 January 2027; the company will then deduct the grant from the price before VAT.
Who pays what, and when: the timetable with a worked example
With pre-financing, you pay the deposit when ordering and the balance at the end, with the grant already deducted; the State then pays the installer. Example for a house installing 6 kWp invoiced at €12,000 incl. VAT.
| Step | You | The installer and the State |
|---|---|---|
| 1. Order | You sign the offer and the statement mandating the installer; deposit of at most €3,600 (30%) | The installer must be listed in the register |
| 2. Installation and declarations | — | Registration with the grid operator, then the end-of-works declaration, required before the grant application |
| 3. Final invoice | You pay the balance: 12,000 − 3,600 − 5,742 = €2,658 | The invoice states the output, the grant deducted and the deposits |
| 4. Grant application | — | The installer files the application on your behalf on MyGuichet.lu |
| 5. Decision and payment | — | Decision within 15 working days (silence means approval), installer paid within the next 15 working days |
With a 7 kWh battery bought at the same time (€18,000 in total), the deposit rises to at most €5,400 and both grants (€5,742 + €2,139) are deducted: the final balance is €4,719. In the standard procedure, you pay the installer in full, then claim the grant yourself after installation: you therefore advance €5,742 until it is paid. The details of that route are on our page on 2026 solar grants.
Pre-financing conditions and exclusions
| Condition | Rule |
|---|---|
| Beneficiary | Owner or holder of property rights in a residential building in Luxembourg, private individual or non-commercial legal entity; a co-ownership acts through its property manager, with the general meeting’s approval |
| System | At least 2 kWp, on the roof or façade, in self-consumption, with the guaranteed feed-in tariff waived |
| Installer | Listed in the register of installers admitted to pre-financing |
| Deposit | At most 30% of the price incl. VAT |
| Documents | Statement co-signed by you and the installer, end-of-works declaration, detailed final invoice |
| Dates | Order signed by 31 December 2029, application by 31 December 2031 |
| Exclusions | Leased systems; a battery added on its own to an existing system; companies carrying on an activity subject to a business permit |
The register of installers admitted to pre-financing
Only an installer listed in the register published by the Ministry of the Economy on guichet.lu can deduct the grant from the invoice. Check the listing before signing: if the installer is not in it, pre-financing is impossible and you will advance the grant. The register can be consulted on guichet.lu, installer register.
Financing the remaining cost: the Klimaprêt
The Klimaprêt is not a zero-interest loan: it is an ordinary bank loan on which the State pays 1.5% of interest a year, without exceeding the loan rate, on capital of up to €100,000 per dwelling over up to 15 years. The total contribution is capped at 10% of the capital, and there is no income condition.
- Conditions: you are the sole owner, the dwelling is over 10 years old, the Klimabonus has already been granted, and the dwelling becomes your main residence within 3 years of the start of works. The base is limited to the costs accepted for the Klimabonus.
- Procedure: form F3 at the Guichet unique des aides au logement, with a partner bank.
- Example: €6,000 borrowed over 10 years with constant capital repayment; the State pays about €500 of interest, below the €600 cap (10% of the capital).
- State guarantee: up to €50,000 on a dedicated mortgage loan; it requires a Klimabonus approval in principle, which only exists for insulation, windows and ventilation. For a solar-only project, ask the Guichet unique whether it is available.
- The zero-interest climate loan no longer exists for new applications.
Lower-income households can also apply for the Topup social Klimabonus, worth 10 to 100% of the Klimabonus depending on income; how it fits with the 2026 scheme, including for solar PV, remains to be confirmed with the Guichet unique des aides au logement.
Leasing, rental and shared installations
A leased solar PV system cannot be pre-financed. If you are offered a rental or leasing contract, have it stated in writing who receives the Klimabonus, who owns the modules, the total cost over the contract and what happens if you sell the house: compare that total with the purchase price minus the grant.
Without a roof of your own, two models let you benefit from a shared installation: collective self-consumption within a building, and the energy community, local or national. The Klimabonus remains possible for a system operated within an energy community. See our guide to solar self-consumption.
Cash, pre-financing or loan: which to choose?
| Your situation | Solution | Why |
|---|---|---|
| You have the savings | Pre-financing, paid in cash | No interest, grant deducted on the invoice |
| You would rather not touch your savings | Pre-financing + Klimaprêt for the rest | 1.5% of interest paid by the State |
| Your installer is not in the register | Standard procedure | You advance the grant, then claim it yourself |
| You are adding a battery to an existing system | Standard procedure | Pre-financing excludes a battery on its own |
| You are offered leasing | Compare the total cost with a funded purchase | No pre-financing with leasing |
What the system earns once financed: see our page on solar payback. Reference prices are on the solar panel cost page.
Pitfalls to avoid with pre-financing
- A deposit above 30%: it falls outside the pre-financing rules. Have it written as a percentage of the price incl. VAT.
- An incomplete statement: it must be co-signed by you and the installer; the final invoice must state the output, the battery capacity, the grant deducted and the deposits.
- A postponed battery: added on its own later, it can no longer be pre-financed.
- The wrong scheme: pre-financing means waiving the guaranteed feed-in tariff; above 10 kWp, compare both options first.
Request quotes with the grant pre-financed
Say that you want pre-financing: installers established in Luxembourg will reply with a quote showing the grant deducted and the deposit. Free and without obligation.
Frequently asked questions about solar pre-financing and financing
How does solar Klimabonus pre-financing work?
You sign the offer and a statement mandating the installer, pay a deposit of at most 30%, then pay the balance with the grant deducted. The installer listed in the register files the application on your behalf and the State reimburses the installer. The grant amount is the same as in the standard procedure.
What is the maximum deposit an installer can ask for with pre-financing?
30% of the system price including VAT. For 6 kWp invoiced at €12,000, the deposit does not exceed €3,600; after deducting the €5,742 Klimabonus, the balance to pay at the end is €2,658.
How can I check that an installer is in the pre-financing register?
The register of installers admitted to pre-financing is published by the Ministry of the Economy on guichet.lu: look up the company’s name there before signing. Without a listing, the installer cannot deduct the grant and you will have to claim it yourself.
Can a battery added later be pre-financed?
No. Pre-financing covers a battery bought together with the solar PV system, not a battery added on its own to an existing system. In that case, you pay for the battery and then claim the grant yourself under the standard procedure.
Can the Klimaprêt finance solar panels?
In principle yes, for the costs accepted for the Klimabonus, once the grant has been awarded: the State pays 1.5% of interest a year on up to €100,000 over 15 years, within a limit of 10% of the capital, with no income condition. The dwelling must be over 10 years old and become your main residence within 3 years. For solar PV, have the eligibility confirmed by the Guichet unique des aides au logement before signing the loan.
Can a leased solar PV system benefit from pre-financing?
No, a leased system is excluded from pre-financing. Before signing a leasing or rental contract, have it specified who receives the Klimabonus, who owns the modules and the total cost over the term, then compare it with a purchase with the grant deducted.
What happens if the administration does not reply to the pre-financing application?
Without a reply within 15 working days, the application is deemed approved. The installer must then be paid within the next 15 working days: the full cycle takes about six weeks after a complete application is filed.