LENOZ (Luxembourgish: ‘Lëtzebuerger Nohaltegkeets Zertifizéierung fir Wunngebaier’, English: Luxembourg residential building sustainability certification) was introduced in 2016. Through LENOZ, the Ministry of Housing is following the recent trend of establishing sustainability certification systems for buildings and building techniques. LENOZ targets official and comparable certification of good practices, to make them more popular. At the same time, the certification can be used to as certification accessing construction and renovation funds.
Rationale for action
For over 40 years, energy consumption has been a quality and sustainability criteria for buildings. Energy consumption alone however does not provide sufficient information on the environmental impact of a building. Important features, such as materials and location also influence the sustainability rating.
The vast variety of construction techniques and materials make it difficult to assess the quality of a building. This applies especially to private developers who make up a large share of the building sector but who need training in assessing the quality of buildings.
LENOZ therefore combines two certification approaches for residential buildings. It certifies the quality of the building and also assesses the environmental impact of a dwelling and its construction process.
In doing so, LENOZ provides guidance for developers and owners on the quality and the environmental impact of their dwelling. Certification can be for new construction, or for existing projects, i.e. renovations. Based on simple, comprehensible criteria, LENOZ provides information for new projects or improvements to existing buildings.
LENOZ certification can equally be used to promote good practices in sustainable and high quality building techniques and materials. The aim is to increase awareness of dwelling quality and sustainability for housing owners and builders.
Additionally, LENOZ can also introduce common certification standards for the public sector, private builders, renovators and construction companies.
LENOZ certification was introduced in 2017.
The players behind LENOZ is the Ministry of Housing as well as building owners and builders.
Implementation steps and processes
LENOZ evaluates six categories; 1) location, 2) social function, 3) energy consumption and costs, 4) ecology, 5) building and technical equipment and 6) functionality. For each category there are several topics and criteria, giving a total of 37 topics and 143 criteria.
Many criteria are binary, with ‘yes’ or ‘no’ answers. This facilitates understanding of the certification for individuals. LENOZ certification is organised around four sustainability classes for housing projects with up to four points for projects in the highest class.
Anyone interested in certifying a dwelling can use information from LENOZ to design the project in cooperation with an architect or an energy consultant. This way, the project can follow the best LENOZ criteria. Applications for certification are submitted to the Ministry of Housing. Finalised projects can also be certified through LENOZ. The six evaluation categories highlight different features of housing projects.
Category 1 ‘location’ is innovative as it complements standard building classifications of energy or materials used (categories 3 and 4). For the location, LENOZ includes spatial planning principles in the evaluation. Under this category, dwellings gain additional points if they are in a decentralised development centre in the country or were developed on a vacant lot within a settlement structure. Dwellings in municipalities certified by ‘KlimaPakt’ (Climate pact) receive additional points.
Based on the total number of points attributed, a different certification level for buildings is issued. There’s a total of four classes, each corresponding to a level of achievement for the evaluated building. Class 1 for ‘very high sustainability’ is attributed for buildings achieving more than 85% for all categories, class 2 for ‘high sustainability’ for buildings achieving between 70% and 85%, class 3 for ‘good sustainability’ for buildings achieving between 55% and 70% and class 4 for ‘minimal sustainability’ for buildings achieving below 55% for all categories.
Owners and homebuilders looking to certify dwellings through LENOZ are supported financially, with EUR 750 per apartment in a multi-apartment house and EUR 1 500 for a single-family home. There is no information on the costs for setting up LENOZ.
LENOZ combines different certification approaches and also uses existing certifications. For example, data from the ‘energy passport’ is used for certain criteria. Since 2010, the energy passport has been mandatory for all buildings on sale or for rent in Luxembourg. The certification of dwellings through LENOZ remains optional.
Experiences, success factors, risks
LENOZ’s broad categories enable a ‘one-size-fits-all’ certification addressing several objectives, issues and features for housing development. By integrating ‘location’ for instance, houses that reduce or limit urban sprawl receive a better certification.
Certification can be used for different purposes. For instance, LENOZ is currently used to access the ‘PRIMe House’ programme where the Ministry of Energy and Spatial Planning financially supports sustainable, energy efficient dwellings.
LENOZ follows a new, comprehensive and combined approach to certifying housing projects. It was only introduced 2017, so uptake can be better seen by reviewing the following years.
Ms Annick Rock, Ministry of Housing: firstname.lastname@example.org
LENOZ general contact address, Ministry of Housing: email@example.com
Ministry of Housing, 2021: LENOZ information site (in French): https://logement.public.lu/fr/professionnels/promoteurs-sociaux/logement-durable0/classification.html
Ministry of Housing, 2019: Explanatory manual (in French): https://logement.public.lu/dam-assets/documents/publications/lenoz/lenoz-manuel-explicatif.pdf
Ministry of Housing, 2019: Procedure for requesting a LENOZ certification: https://guichet.public.lu/en/entreprises/urbanisme-environnement/energie/energie/certificat-lenoz.html