FAQ

Calculation of the environmental indicators is directly linked to calculation of the thermal transmittance U and its inherent calculation rules. However, the layers of membranes and seals, which are negligible when calculating the thermal transmission coefficient given their low impact in terms of their insulation capacity, should be taken into consideration for calculation of the predicted environmental indicators.

For a new building, the construction elements of the thermal envelope (= external structure) as well as internal walls and slabs are taken into account.

For the elements of the external structure, all the layers taken into consideration for calculation of the U value are also taken into consideration for calculation of the I _env and I_prim indicators.

Party walls and partition walls between different units in a block of flats should be considered internal walls (within the building envelope).

For existing buildings, only new insulating materials used during the retrofitting works are taken into consideration.

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.

The approved energy adviser is responsible for:

• carrying out on-site energy consulting;
• drafting the "conclusive report" (a comprehensive inventory of the property in question, the content of which must include a description of the property, the date of the site visit, the energy performance certificate prior to the retrofit and an integral energy renovation concept);
• checking the conformity of the offers to the measures proposed in the above-mentioned energy retrofitting concept;
• checking the conformity of the implementation on site with the measures proposed in the energy retrofitting concept;
• drafting a final report that must be attached to the request for payment of financial aid; 
• completing the forms for the request for an agreement in principle and for the payment of financial aid.

Yes, the EPC training courses developed by the Ministry are open to everyone, including municipal employees. They can be booked on the Internet portal www.guichet.lu/experts-energie. In addition, in 2017 a workshop was organised on the subject of site inspections led jointly by the Ministry of the Economy, Klima-Agence and Syvicol. Klima-Agence is also prepared to strengthen its collaboration with the municipalities. If necessary, the municipality can contact the qualified adviser at Klima-Agence. Some additional EPC training courses are also available on the main Luxembourg training portals.

• Demolition: sale of a ruin or a building that does not have a heating installation and which will be demolished after purchase.
• Inheritance or gift.

• New building: any building that is subject to a building permit application. (A feasibility study concerning the use of renewable energies should be appended to the building permit application.)
• Extension of an existing building.
• Modification of an existing building (building permit required), if the surface area of the modified element of the thermal envelope exceeds the surface area of the same existing element (walls, windows, roof, etc.) by 10% and if the modification has an impact on the energy performance of the building. (Issuance of an energy performance certificate for the new planned situation.)
• Substantial alterations to an existing building (without a building permit), if the surface area of the altered element of the thermal envelope exceeds the surface area of the same existing element (walls, windows, roof, etc.) by 10% and if the alteration has an impact on the energy performance of the building. (Issuance of an energy performance certificate for the new planned situation.)
• Change of owner or tenant.
• Demolition: sale of a building that will be demolished after purchase, if the building has a heating installation, exterior walls and a roof.
• Modification of technical facilities, if the modifications of these technical facilities exceed €1,500 (for a single-family house) or €3,000 (for a multi-family house).

The energy performance certificate is a regulatory obligation, therefore no subsidy is provided for its establishment.
The energy performance certificate is issued according to precise rules set out in the amended Grand Ducal Regulation of 30 November 2007 on the energy performance of residential buildings. It is valid for 10 years from the day of its issue. The issuance of an energy performance certificate and the information it contains shall not result in any direct obligation for energy retrofitting.

The energy performance certificate (EPC) or energy passport is the quality label that defines the energy performance of a residential building. The certificate provides information on the energy efficiency of residential buildings and thus allows comparisons to be made with other residential buildings. Thus, even without technical knowledge, the consumer can assess the energy quality of a residential building.