Insulation subsidies in Luxembourg 2026: Klimabonus rates per m²

How much the state pays per m²

The rate depends on where the element is, the insulation material and the performance standard reached (III, II or I, where I is the best). The amount in brackets applies when the approval in principle is requested between 1 January 2026 and 30 June 2027 and the invoice is issued by 31 December 2030.

"Against an unheated space" covers the ceiling of an unheated cellar, the floor of an unheated attic, and walls next to unheated rooms.

Example: 120 m² of outside wall insulated with a mineral material to standard II gets 120 × 80 € = 9.600 € when the approval in principle is requested by 30 June 2027, and 120 × 70 € = 8.400 € after that.

Adjustments

• Insulation on the inside only: the rate is 25 % lower.
• +15 €/m² for mineral insulation with at least 50 % recycled content, for eco-friendly insulation from certified sustainable crops, and for a green roof or green outside wall.
• Fossil-based materials (synthetic insulation) get no aid unless they contain more than 50 % recycled material, except on walls against the ground, green roofs, green walls and floor slabs against the ground.

What each standard requires

Standard III is a minimum thickness, measured for a material with a conductivity of 0,035 W/(mK). Standards II and I are a maximum U-value in W/(m²K). The standard III thickness is required for every standard.

Conditions

• Building age: the house or flat must be more than 10 years old, counted from the building permit, when you apply.
• Approval first: the approval in principle must be requested before the work starts. Work started without it is not subsidised.
• Who does the work: an approved business, or work monitored by an approved energy consultant. The consultant's help is itself subsidised: 100 € for checking the quotes and 400 € for checking the work on site.
• Heated attic: if the roof is renovated, roof windows older than 10 years with a U-value above 1,4 must be replaced by windows with U ≤ 1,4.
• Deadlines: the first approval in principle between 1 January 2026 and 31 December 2030, invoices up to 31 December 2035.

1. 01Quote with m² and materialAsk for the area per element, the insulation material and the thickness or U-value reached, so the rate can be read off the table.
2. 02Approval in principleBefore any work starts, a registered energy adviser or tradesperson applies for the approval in principle with the DESC form and the signed quote.
3. 03WorkDone by an approved business, or monitored by an approved energy consultant. A changed concept needs a new approval.
4. 04PaymentAfter the work, apply with the CONF-2026 confirmation, the invoices and proof of payment, at the latest 4 years after 31 December of the invoice year.

With a full energy assessment

If you plan several measures, an approved energy adviser can assess the whole building first. The same rates per m² apply, and:

• the aid for the insulation rises by 20 %, 30 % or 50 % when the building improves by at least two energy classes and reaches class C, B or A;
• the assessment itself gets 1.700 € for a house (2.000 € when the approval is requested by 30 June 2027), never more than its cost;
• ventilation with heat recovery gets 60 € (70 €) per m² of heated floor area.

Pre-financing from 2027

From 1 January 2027, a company listed in the register of intermediary applicants can file the application and deduct the aid from your invoice. Each insulation measure then needs its own application and its own invoice.

Commune top-ups and 3 % VAT

Many communes add a share of the state aid, most often 10 %, 25 % or 50 %, with a cap that differs from one commune to the next. Klima-Agence's aid simulator shows the amounts for your commune. Facade and roof work on a main residence older than 10 years can be invoiced at 3 % VAT instead of 17 %; see 3 % VAT on renovation.

What to ask for in your quotes

• The area in m² for each element, with the element type (outside, ground or unheated space).
• The insulation material and its category: fossil-based, mineral or eco-friendly.
• The thickness and the U-value reached, so you know the standard.
• Who files the approval in principle, and a separate invoice for each element.

Windows have their own page: window subsidies.