FAQ

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.

For existing buildings, only the primary energy requirement of the technical installations for conditioning the building should be considered for the I_prim indicator (Chapter 4.2). The primary energy expenditure of the existing building is not taken into account. 

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 values of the I_eco12 indicator are provided for some commonly used insulation materials in Chapter 7.3 of the Annex to the Grand Ducal Regulation on the Certification of the Sustainability of Housing and can be reused.

In the event that other insulation materials are used, experts can calculate the I_eco12 indicator using the I_calc calculator, which can be viewed online 

The I_eco12 indicator is used to assess new insulation installed on an existing building and is taken into consideration in the following cases:

• in the case of sustainable energy retrofitting of elements of the thermal building envelope under the Klimabonus subsidy scheme;
• as part of the LENOZ certification of an existing retrofitted building.

The indicator I_eco12 represents the environmental impacts (I_env) and the impacts induced by the primary energy requirement (I_prim) of an insulation material, evaluated on an equivalent thickness of 12 cm. This results in an independent environmental assessment of the existing building, while taking into account the grey energy consumed by the insulation material.

As is the case for buildings along the municipal public domain, buildings along the State road (national road and State-managed road) must, within the framework of the building permit application procedure, comply with the municipal urban planning regulations on setbacks.

For constructions located in the vicinity of the State public domain at a distance of 25 metres from a national road (N) or at a distance of 10 metres from a State-managed road (CR), established from the property line, a road permit is required from the Minister of Sustainable Development and Infrastructure. As part of a road permit, provisions regarding the setbacks of buildings in relation to the road will be applied. These may differ from the setbacks set by the municipalities.

• 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).