Energy Audit and CPE in Luxembourg: Complete Guide 2026

The energy audit in Luxembourg: an essential step

In Luxembourg, the energy audit is the tool that lets you plan a renovation in the right order. Carried out by a certified energy consultant, it assesses the thermal performance of your building and proposes a prioritised action plan aimed at a higher energy classification (class A, B or C).

It matters financially, not just technically: as soon as you renovate more than one element of the thermal envelope, the energy consultation (conseil en énergie) is mandatory to access the Klimabonus. And for energy renovation of the envelope, the agreement in principle must be obtained before the works start. Get that order wrong and the aid is lost, whatever the quality of the works.

Klimabonus, PRIMe House: which scheme are you actually in?

The two names are constantly mixed up, so here is the timeline.

• PRIMe House is the closed 2017 scheme. It concerns you only if your energy consultancy was established before 31 December 2021 and your invoices are dated between 2017 and 2024. Those files remain admissible until 31 December 2026, and not beyond.
• Klimabonus has been the name of the scheme since 1 January 2022, the date on which it replaced PRIMe House.
• The 2026 reform changes the flat-rate amounts and several conditions inside Klimabonus. It does not rename the scheme. Guichet.lu also notes that applications can be filed from 1 January 2026 with retroactive effect, but that their processing remains subject to publication of the law in the Official Journal.

The practical consequence: any page still promising you up to 50% of your costs, capped at €15,000 is describing PRIMe House. The 2026 Klimabonus pays a flat rate per m2 of renovated surface for insulation, not a share of your invoice.

The CPE: what is it?

The certificat de performance énergétique (CPE), also called the Energiepass, is the Luxembourg energy passport, the local equivalent of the Belgian PEB or the French DPE. It rates the building from A+ (most efficient) to I (least efficient) on the basis of three indexes:

• the primary energy requirement, which gives the energy performance class;
• the heating energy requirement, which gives the thermal insulation class;
• the building's CO2 emissions, which give the environmental performance class.

The CPE is mandatory when selling, letting, renovating, extending or constructing a residential building. Sales and rental advertisements must state the energy performance class and the thermal insulation class. It is valid for 10 years, and it is established by an architect, an engineering consultancy firm or an expert approved by the Ministry of the Economy.

For a new building, the owner must complete the certificate with a measured consumption index for heating and hot water within 4 years at the latest.

Difference between the CPE and an energy audit

• CPE: a standardised document that classifies the building. Mandatory for sale, letting, renovation, extension and construction. Valid 10 years. It carries improvement recommendations for existing buildings, but it is not a costed renovation plan.
• Energy audit / energy consultation: an in-depth analysis with a step-by-step renovation plan, cost and saving estimates and a target classification. It is the document that unlocks the Klimabonus as soon as several envelope elements are involved.

Energy audit prices in Luxembourg in 2026

There is no official tariff for these services: the figures below are indicative market ranges and vary with the size and complexity of the building. Always compare several quotes.

The energy consultation is itself subsidised: €1,700 for a single-family house and €2,000 for a building with 2 flats, plus €60 per additional flat, capped at €3,000. Where the increased amounts apply, that becomes €2,000 for a house and €2,500 to €3,750 in a multi-dwelling building. The aid is only granted if at least one energy efficiency measure is actually carried out, it can never exceed the real cost of the assessment, and the consultation invoice must be issued between 1 January 2026 and 31 December 2030 inclusive.

If you renovate a single element without a full consultation, the works must be done by an approved business or in the presence of an energy consultant. A consultant who occasionally monitors the works can bring €400, plus a €100 supplement for verifying the conformity of the estimates.

The energy consultant: a key player

In Luxembourg the certified energy consultant sits at the centre of a renovation file:

• carries out the energy consultation and, where qualified to do so, the CPE;
• builds the file that supports the Klimabonus application;
• advises on materials, insulation standards and the order of works;
• can verify the conformity of the works and of the estimates;
• is listed among the Klima-Agence certified advisers.

Note that three routes exist, depending on the project: more than one envelope element means the energy consultation is mandatory; a single element means either an approved business or an energy consultant; technical installations (heating, ventilation, renewables) leave no alternative at all, a trade professional is required.

Klima-Agence, formerly myenergy: the one-stop shop

Klima-Agence is the national advisory structure for energy and renovation. It is the same organisation that used to be known as myenergy: the myenergy.lu address now redirects to klima-agence.lu. Its services are free for private individuals:

• telephone and online advice on energy renovation;
• directory of Klima-Agence certified advisers;
• information on the Klimabonus and on the other available support;
• events and information sessions for owners.

Applications themselves are filed with the Guichet unique des aides au logement, and the aid is granted by the Administration de l'environnement (AEV). No processing time is published by the Guichet unique, so no serious professional can promise you one.

Deadlines you cannot afford to miss

• Agreement in principle before the works start for energy renovation of the envelope.
• First application for an agreement in principle: between 1 January 2026 and 31 December 2030 inclusive.
• Eligible invoices: 1 January 2026 to 31 December 2035.
• Aid claimed within 4 years from 31 December of the year of the invoice, and by 31 December 2039 at the latest.
• Exception: photovoltaic panels and batteries are applied for after the works, with no agreement in principle.
• The building must be more than 10 years old from the date the building permit was issued. Since 2026, the age of the boiler being replaced is no longer a criterion.

Topup Klimabonus: the aid that can double yours

The Topup Klimabonus is a separate aid from the Ministry of Housing, formally the prime d'amélioration pour assainissement énergétique. It is worth 10% to 100% of the Klimabonus already granted, depending on the composition and income of your household.

• You must already have obtained a Klimabonus from the Administration de l'environnement.
• The application must be filed within 2 years of that grant decision, otherwise the right lapses.
• It cannot be combined with the classic prime d'amélioration.
• All capital housing aid combined is capped at €35,000 per beneficiary.
• Income ceilings apply, and the dwelling must be your main and permanent home for at least 2 years from the date the aid is granted.

VAT at 3%: get the condition right

Renovation of housing assigned to main residence use can benefit from the super-reduced rate of 3%, against a standard rate of 17%. Two routes exist: substantial works on a dwelling whose construction is at least 10 years old at the start of the works, carried out within 2 years from their commencement; or works completed within 5 years of an acquisition.

The frequently repeated « dwelling more than 2 years old » is wrong: those 2 years are the period of assignment to main residence use after the works. The « more than 20 years » figure is obsolete.

• Direct application of the 3% rate: quote of at least €3,000 excluding VAT, request filed before the works start.
• Reimbursement afterwards: each invoice of at least €1,250 excluding VAT, and the request must cover a minimum period of six months.

In both cases the advantage is capped at €50,000 per dwelling.

Request your free quotes

Have your CPE or your energy consultation carried out by a certified professional working in Luxembourg. Receive up to 5 free and non-binding quotes, then file your Klimabonus application in the right order: quotes, agreement in principle, works.