FAQ

A LENOZ certificate can be issued for all residential buildings with an energy passport, whether they are new or existing residential buildings.

Issuance of the certificate is associated with Class 4 “minimum sustainability” (Chapter 0.2 of the Annex to the Grand Ducal Regulation on housing sustainability certification).
Existing residential buildings can achieve this "minimum sustainability" by means of comprehensive retrofitting works.

No, LENOZ is an optional certificate that provides information to the main contractor and the owner about the level of sustainability of a residential building.

The following persons are authorised to issue LENOZ certificates:

• architects and engineers within the meaning of the Law of 13 December 1989 organising the professions of architect and consulting engineer;
• accredited persons within the meaning of the Law of 5 August 1993 on the rational use of energy;

• energy consultants within the meaning of the Act of 21 April 1993 on the approval of natural persons or legal entities, private or public, other than the State, for the performance of technical study and verification tasks in the environmental field.

For the preparation of a LENOZ certificate, you can apply for financial aid (preparation grant) amounting to €1,500 gross per single-family home and €750 gross per flat in a block of flats.

A LENOZ certificate includes an estimate of the sustainability of a residential building, calculated on the basis of six categories: location, society, economy, environment, building and technical installations, and functionality. The certificate includes the sustainability class and the points obtained per category/criterion.

LENOZ is an optional global assessment strategy, adapted to the Luxembourg market, for quantifying the sustainability of housing. LENOZ stands for Lëtzebuerger Nohaltegkeets-Zertifizéierung.

The operator of a facility – in this case, you as an individual – is liable for the construction and operation of the facility in compliance with the applicable provisions and for all damages that may result therefrom. You should therefore check carefully that the drilling documents are complete. These should include:

the completed pressure test form as proof of the tightness of the geothermal probe once the probe has been placed (ask the drilling company if this report complies with VDI Guideline 4640);
the complete drilling report.

No. The Law of 19 December 2008 on water prohibits the direct or indirect discharge of water as well as other solid or gaseous substances. Groundwater heat pumps cannot therefore be authorised in Luxembourg.

• The size of the installation must be calculated in accordance with VDI (Association of German Engineers) Guideline 4640. Ask your chosen drilling company for information on this subject.
  In addition, you can also have a heat load calculation and a geological survey carried out in order to establish the sizing.
• You must ensure that you have obtained all necessary permits before the works start.
• The exact date of the start of drilling must then be notified to the water management authority in advance. Ensure that the drilling company and the installer coordinate their schedules.
• Plan appropriate access to the site in advance.