Applying for a LENOZ certificate for a building

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In 2017, Luxembourg introduced its own environmental certification scheme for residential buildings.

LENOZ (tzebuerger Nohaltegkeets-Zertifizéierung – Luxembourg sustainability certification) is designed to serve the specific needs of the residential sector (single-family houses and multi-unit residential buildings in Luxembourg).

LENOZ certification is optional. Its purpose is to:

  • raise awareness of sustainable housing;
  • bring more transparency to the property market: the certificate provides a great deal of information about the certified dwelling.

The certificate:

  • serves as a guide throughout the entire construction process;
  • can be used to assess the consequences of decisions taken by the owner of the building, not only in terms of energy efficiency but also in terms of:
    • the sustainability of the home;
    • its location;
    • indoor air quality.

The LENOZ certificate is based on data provided in the building's energy performance certificate.

LENOZ certificates can be issued by architects, consulting engineers, energy consultants and other professionals authorised to issue energy performance certificates.

The Ministry of Housing and Spatial Planning (Ministère du Logement et de l’Aménagement du territoire) grants financial support to building owners wishing to apply for a LENOZ certificate for their residential property.

Who is concerned?

The LENOZ certificate for a residential building must be applied for by:

  • the owner of a single-family home or a multi-unit residential building;
  • the building's developer, if they are the owner;
  • the co-ownership trustee, on behalf of the co-owners of a multi-unit residential building.

The certificate can be issued for:

  • any new residential building;
  • any substantial or comprehensive energy enhancement works;
  • any residential building or part thereof for which an energy performance certificate has been issued.


The person applying for the LENOZ certificate will be required to pay the cost of having it drawn up.

Financial aid may be granted by the Ministry of Housing and Spatial Planning to cover the cost of having the certificate drawn up.

How to proceed

LENOZ certification

The certification covers 6 assessment categories (comprising 143 criteria):

  • location: criteria relating to the location of the dwelling;
  • social: criteria used to assess the social features of a multi-unit building and how the floor space is used;
  • savings: criteria used to assess the energy costs for the dwelling;
  • environment: criteria used to assess, among other things, the environmental impact of the building materials used;
  • building and technical installations: criteria relating to the quality of the building and its technical installations;
  • functional features: criteria used to assess the adequacy of the dwelling for its intended use.

The sustainability certificate is drawn up by the expert handing the file, and shows the building's sustainability classification:

  • class 1: very high level of sustainability (4 LENOZ leaves), satisfying 85 % of the criteria;
  • class 2: high level of sustainability (3 LENOZ leaves), satisfying 70 % of the criteria;
  • class 3: good level of sustainability (2 LENOZ leaves), satisfying 55 % of the criteria; and
  • class 4: minimal sustainability (1 LENOZ leaf), satisfying 40 % of the criteria.

 Applying for a LENOZ certificate

The certificate is issued by:

  • an architect;
  • a consulting engineer;
  • an energy consultant;
  • a professional approved to perform technical tasks for the purpose of energy-related studies or inspections, and more particularly for the purpose of:
    • carrying out energy audits;
    • determining the energy performance of buildings and issuing energy performance certificates.

It is recommended that all such professionals take a LENOZ course.

The list of experts who have completed a LENOZ course is updated on a regular basis.

Applicants may contact an expert of their choice.

The LENOZ certificate must be issued in as many original copies as there are owners of the certified building.

Each owner must possess an original copy of the sustainability certificate.

Documents required for a LENOZ certificate

The applicant must enclose the following documents:

  • a copy of the energy performance certificate;
  • a cadastral map;
  • a layout plan;
  • plan views;
  • sectional plans;
  • elevation plans, showing walls, etc.

Before issuing the certificate, the expert may require other documents.

Validity period

LENOZ certificates are valid for 10 years from their date of issue. The date of issue and expiry date are shown on the certificate.

The certificate will cease to be valid if a new energy performance certificate needs to be issued for the dwelling in question.


In the case of a building held in co-ownership, the decision to apply for a LENOZ certificate is taken by majority vote of the co-owners present or represented. As such, a minority of co-owners cannot oppose an application for a LENOZ certificate.


A potential buyer or tenant who has expressed an interest in purchasing or renting a dwelling, whose owner has expressed their interest in selling or letting the dwelling in question, must be able to consult the sustainability certificate issued for the dwelling in question and for whose issuance the owner received financial support.

The Ministry of Housing and Spatial Planning keeps a register of all residential housing sustainability certificates and their annexes.

In the event of a change of ownership, the owner in possession of the sustainability certificate must give the original copy of the certificate to the new owner.

Who to contact

Ministry of Housing and Spatial Planning

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