Klimabonus 2026: the per-square-metre rate for roof insulation in Luxembourg

What is the Klimabonus Wunnen 2026?

The Klimabonus Wunnen 2026 is the 2026 scheme of the Klimabonus financial aid program for energy renovation in Luxembourg, whose new amounts have applied since January 2026 (law of 24 July 2026). It updates the rates of the Klimabonus, which itself replaced the former PRIMe House program in January 2022, and aims to encourage homeowners to improve the energy efficiency of their homes. The goal is to reduce CO2 emissions and lower household energy bills. This program is managed by the Klima-Agence in collaboration with the one-stop shop (MyGuichet.lu).

For roof insulation, the Klimabonus pays a rate per square metre refurbished: from 35 to 115 EUR/m² depending on the insulant and the performance standard reached, and up to 140 EUR/m² with the transitional increase (agreement in principle applied for between 01/01/2026 and 30/06/2027, invoice by 31/12/2030 at the latest). Other work is covered by separate aid schemes, such as a photovoltaic system (8,250 EUR for 10 kWp, a flat 10,000 EUR from 15 kWp) or a home battery linked to it (up to 2,250 EUR, reached from 9 kWh of usable capacity).

Eligibility Conditions for Roof Insulation

To benefit from the Klimabonus for roof insulation, several conditions must be met:

• Eligible dwelling: Main or secondary residence located in Luxembourg, in a residential building more than ten years old (counted from the building permit, on the date of the application for an agreement in principle). The super-reduced VAT of 3% has its own age requirement (otherwise standard VAT of 17% applies).
• Minimum performance: the law of 24 July 2026 (Annex II) requires at least 20 cm of insulant at λ 0.035 W/(mK), converted pro rata for another insulant (about 22.9 cm at 0.040), whatever the standard you aim for. For standard II, the insulated roof must also reach U ≤ 0.13 W/(m²K); for standard I, the most demanding and best-funded level, U ≤ 0.11 for a pitched or flat roof and U ≤ 0.10 for the floor of an unheated loft. If the loft is heated, roof windows older than 10 years with a U-value above 1.4 W/(m²K) must be replaced by windows with U ≤ 1.4.
• Materials: mineral insulant (glass wool, rock wool), ecological insulant (plant or animal fibres, fixed mechanically) or fossil-based insulant made of more than 50% recycled material. Non-recycled fossil insulants such as standard polyurethane or polystyrene do not qualify, except on a green roof.
• Approved company or adviser: if only the roof is renovated, the work must be carried out by a company approved under the law of 21 April 1993 or followed by an energy adviser; as soon as several elements are renovated, energy advice is mandatory before applying.

Additionally, depending on the work (raising the roof or changing its appearance), a municipal permit may be needed: check with your commune.

Aid Amounts per Square Metre

The table below summarizes the key amounts of the Klimabonus for roof insulation:

Note that the amount is proportional to the area actually refurbished: it is not a percentage of the quote. Insulation fitted exclusively on the inside is reduced by 25%, while a mineral insulant more than 50% recycled, an ecological insulant from certified sustainable crops, or a green roof each add 15 EUR/m².

How to Apply?

The application procedure is entirely online via MyGuichet.lu, the official portal for administrative procedures in Luxembourg. Here are the steps:

1. Get a quote: Contact a qualified artisan to obtain a detailed quote for the insulation work.
2. Create a file: Log in to MyGuichet.lu with your ID (or create an account). Select the form "Klimabonus Wunnen - Aid application".
3. Submit the quote: Attach the quote signed by the artisan and fill in the required information (area to insulate, materials, expected performance).
4. Receive approval: The Klima-Agence processes your application within 4 to 6 weeks. Once approved, you receive an approval letter valid for 12 months.
5. Carry out the work: Have the work done by the artisan within the given timeframe.
6. Request payment: After the work, submit the paid invoice and proof of performance (certificate from the artisan or thermal measurement). Payment is made within 2 to 3 months.

Important: the application must be made before the start of work, otherwise the aid is refused.

Additional Tax Benefits

In addition to the Klimabonus, homeowners can benefit from a super-reduced VAT rate of 3% on energy renovation work, provided the home was meeting the age requirement. This rate applies to labor and materials, provided the company invoices the client directly. Where the conditions are not met, the standard rate of 17 % applies.

Furthermore, loan interest for financing the work may be deductible from rental income (if the property is rented) or qualify for a tax credit under certain conditions. Check with the Administration des contributions directes.

Concrete Financing Examples

Take the example of a single-family home in Luxembourg City with a 100 m² roof to insulate using sarking. The artisan's quote amounts to 30,000 EUR (materials and labor). With a mineral insulant reaching standard II, the rate is 70 EUR/m², i.e. 7,000 EUR of aid for the 100 m² refurbished — and 8,000 EUR with the transitional increase. Aiming for standard I with an ecological insulant (115 EUR/m², 140 EUR/m² increased) raises the aid to 11,500 EUR, or even 14,000 EUR. On top of that, VAT at 3% (900 EUR on 30,000 EUR) instead of 17% (5,100 EUR) saves a further 4,200 EUR. In every case, the aid is capped at 60% of the costs of the work excluding VAT.

Another example: attic insulation for a 50 m² area, quote of 12,000 EUR. The floor of an unheated loft falls under the lower rate for an upper slab against an unheated zone: with a mineral insulant at standard III (25 EUR/m²), the aid is 1,250 EUR, rising to 1,500 EUR with the transitional increase (30 EUR/m²).

Tips to Maximize Your Aid

• Get multiple quotes: Compare offers from at least 3 artisans to get the best value for money.
• Check performance: Ensure the proposed insulation reaches at least 20 cm at λ 0.035 (or the equivalent thickness for its conductivity) and, if you aim for standard II or I, that the quote states the U-value of the roof after the work. Ask for a technical data sheet.
• Anticipate delays: Applications are processed within 4 to 6 weeks. Do not start work before approval.
• Keep all documents: Quotes, invoices, performance certificates are needed for payment.
• Plan each aid: If you also install solar panels or a heat pump, each installation falls under its own aid scheme, with its own conditions and its own cap.