Klimabonus Window Grant: 70 EUR/m2 in Luxembourg 2026

What is the Klimabonus window grant?

Since January 2026, the Klimabonus Wunnen program has replaced the old PRIMe House scheme. Managed by the Klima-Agence and the Ministry of Energy, it offers a grant for replacing window frames (windows, French doors) of 70 EUR per square meter of glazing replaced. This measure encourages thermal insulation of older homes, as windows are responsible for 10-15% of heat loss.

The 70 EUR/m2 applies to the glazing only, not the full frame. In practice, the grant is calculated on the glazing area of each window or French door replaced. For example, a standard window of 1.2 m x 1.3 m has a glazed area of about 1.2 m2, giving a grant of 84 EUR for that window.

To be eligible, the home must be located in Luxembourg and completed for more than two years. Works must be carried out by a company registered in Luxembourg, and materials must meet specific energy performance criteria.

Eligibility conditions for glazing

The installed glazing must have a thermal transmittance coefficient (U-value) less than or equal to 1.1 W/m2K. This typically corresponds to low-emissivity double glazing with argon gas, or triple glazing. The frame itself can be wood, PVC, aluminum, or mixed, but the glazing must meet the criterion.

Additionally, works must be part of the home's energy renovation. It is prohibited to replace windows in a room that is not part of the dwelling (e.g., an unheated garage). The application must be submitted before work begins, and Klima-Agence approval is necessary to guarantee the grant.

• The home must be your primary residence or rented (in which case the landlord can apply).
• Windows must be installed by a professional company and invoiced with VAT.
• The minimum area of glazing replaced is 1 m2 per project (or 0.5 m2 for doors).

How to apply?

Applications are submitted exclusively online via the Klima-Agence portal or through the single desk guichet.public.lu. Here are the steps:

1. Create an account on the Klima-Agence portal (klima-agence.lu) or use your LuxTrust credentials.
2. Fill out the application form for window replacement.
3. Attach required documents: detailed quote from the company, site plan, proof of home age (sales deed or building permit), and if possible a photo of existing windows.
4. Submit the application before work starts. Written approval from Klima-Agence is mandatory before ordering new windows.
5. After completion, send the paid invoice and photos of the new windows. The grant is paid into your bank account within 4 to 6 weeks.

It is highly recommended to consult an energy advisor to verify your project's eligibility and help you prepare the file. Some communes even offer free assistance.

Amounts and caps

The grant is 70 EUR per m2 of replaced glazing, with no specific cap for this item. However, the Klimabonus Wunnen program caps total aid for a home at 50,000 EUR over a rolling 5-year period. If you combine multiple works (insulation, heat pump, etc.), you must respect this overall cap.

Here are some calculation examples (for reference):

For a typical single-family house, the grant can cover 10-20% of the total cost of replacing frames, depending on the chosen joinery type.

Combining with other aids and reduced VAT

The window grant can be combined with other Klimabonus aids, such as roof insulation or heat pump installation. For example, if you insulate your roof and replace your windows, you can get both grants. The 50,000 EUR cap applies to the total.

Moreover, renovation works in a home over 2 years old benefit from the reduced VAT rate of 3% (instead of 17%). This reduction applies to labor and materials, provided the home is actually used as a residence. This represents a significant additional saving.

It is also possible to combine the grant with communal aids. Some communes offer additional subsidies for windows. Check with your local administration.

Common pitfalls and mistakes to avoid

Here are the most frequent errors that lead to grant refusal:

• Starting work before obtaining written approval from Klima-Agence.
• Installing glazing with a U-value higher than 1.1 W/m2K.
• Not keeping original invoices and proof of payment.
• Replacing only part of the window without changing the complete glazing (the grant applies to the entire glazing).
• Forgetting to attach the site plan of the home.

To avoid these pitfalls, it is advisable to work with a craftsman who knows Klimabonus requirements well. A good professional will provide a technical data sheet for the glazing and help you fill out the form.

Energy impact and comfort

Replacing your windows with high-insulation models significantly improves thermal and acoustic comfort. In winter, indoor temperature is more stable and drafts disappear. In summer, low-emissivity glazing reduces overheating. Energy-wise, savings can reach 20-30% on heating bills, depending on the building's initial condition.

Additionally, a well-insulated home has higher property value. Potential buyers are sensitive to energy performance, and the energy performance certificate (EPC) will be more favorable.

Typical project example

Consider a single-family house built in 1990 in Luxembourg City. The owner wants to replace 12 windows and 2 French doors. The total glazed area is 25 m2. The total cost of works (supply and installation) is estimated at 18,000 EUR excluding VAT.

With the window grant, he will receive 25 x 70 = 1,750 EUR. Thanks to the 3% VAT, he saves 14% VAT, about 2,520 EUR compared to normal VAT. In the end, the net cost for the owner is about 18,000 - 1,750 - 2,520 = 13,730 EUR. This calculation illustrates the benefit of combining aids.

To maximize aids, the owner could also consider insulating the roof in the same year, as both grants are combinable and the 50,000 EUR cap leaves room.