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.

Objective

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.

Time frame

LENOZ certification was introduced in 2017.

Key players

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.

LENOZ certification label. Source: Ministry of Housing, 2019.

Required resources

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.

Results

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.

Conclusion

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.

Contact

Ms Annick Rock, Ministry of Housing: annick.rock@ml.etat.lu

LENOZ general contact address, Ministry of Housing: lenoz@ml.etat.lu

Further reading

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

Late 2020, we interviewed Ms Lydie Polfer, Mayor of Luxembourg City on the role and potential of climate change adaptation in urban planning and municipal development. The interview also addressed questions on climate action in the capital of the Grand Duchy of Luxembourg.

Interviewer: Ms Polfer, measures addressing climate change can be for climate action, such as measures decreasing hazardous emissions, or for adaptation, so measures dealing with the consequences of climate change. What role does urban and district development play in adapting to climate change?

Mayor Polfer: Climate change adaptation and also climate action are key aspects that need to be considered together when planning in urban areas. On the one hand, climate actions reduce emissions of inhabitants and businesses in a district. On the other hand, climate change adaptation helps to protects inhabitants from natural hazards resulting from climate change.

There is a wide range of possible measures for climate action in the urban environment. For example, in Luxembourg City, we focus on reducing the need for transport by creating functional mixtures in the urban pattern. We adopt circular economy approaches, enabling building material to be reused and recycled in urban construction and we favour net-zero-energy buildings. These measures all have a positive impact on the energy footprint. To reduce this footprint, sustainable transport is also important. Just to give an example, Luxembourg City is a frontrunner in electric public mobility and about 30 % of the city busses are electric as of today in 2020.

For climate change adaptation, we focus on renaturalised rivers and waterways to increase absorption of rainwater in urban areas. We test technical measures for rainwater retention in ponds or temporary reservoirs and we try to limit the amount of soil sealed in existing and newly built-up urban areas. The guiding documents for our city to address climate action and climate change adaptation are the Municipal Environmental Report and Action Plans. These annual reports and plans orient Luxembourg City measures. They help us to work towards a good and secure urban life, and an urban life in line with sustainability objectives.

Interviewer: Where do you see priorities or opportunities to use existing or new spatial planning and urban development instruments for climate change adaptation in Luxembourg?

Mayor Polfer: The City of Luxembourg uses three complementary planning instruments for climate change adaptation. The land-use plan, so-called PAG, the special development plan, the PAP, and the Municipal Building Regulation, defining requirements and technical specifications for buildings and infrastructure.

The PAG is used for zoning areas and defines density requirements and limitations to soil sealing. With the PAP and the Municipal Building Regulation, the municipality uses two more nuanced instruments. These enable our municipal planners to take decisions on the future layout of areas and the location, orientation and shape of buildings. They also detail surfaces to be kept unsealed, and even define materials to be used. Also, we look to optimise the number of parking spaces to keep areas open that are usually sealed. This way, we integrate various elements in our plans to ensure that transformations and new developments are adapted to climate change. And of course, for climate action, these tools work equally well.

We conduct many experiments in urban planning practices and we research experimental building techniques. This leads to a high number of innovations in the building sector, especially in view of climate change. An example is the use of grey water, or rainwater in large residential buildings or greening roofs, for which new concepts are being tested. To benefit from the latest innovations, we need measures that allow us to design the district differently. Faster procedures and increased openness of projects towards new insights and concepts on climate action and adaptation in planning is required.

Interviewer: What potential for climate change adaption is there from converting urban brownfields?

Mayor Polfer: In conversion or re-conversion projects, for example ‘Porte de Hollerich’ or the 10 hectare area of ‘Josy-Barthel’, planners have a free hand. When we develop a district from scratch, we face fewer limitations. We also need to compromise less when it comes to implementing climate change adaptation measures. For example, a river can take its natural course again, an inundation area can fulfil its initial function. It also provides us with unique opportunities to design park areas as both zones helping to adapt the city to climate change and also as recreation areas for inhabitants of the districts.

Planning on unbuilt land also allows us to develop a priori climate change adaptation and action concepts that guide urban design and the layout. This way, the best option, yielding the best protection or adaptation can be planned and tested before being realised. We look at such concepts not just at the neighbourhood level but also for the district. Hence these new urban developments are key to increasing the resilience of our city, as changes to existing urban districts are limited for various reasons.

However, the question of ownership significantly influences climate change adaptation measures in such urban projects. Unless all land is owned by the City of Luxembourg, we rely on a consensus between all owners on what climate change adaptation measures will be implemented. If an owner does not approve, the procedure is postponed, or the plans have to be amended, compromising on the planned adaptation measures.

Interviewer: How can one combine the persistently high pressure on the housing market with measures of climate change adaptation, in your opinion?

Mayor Polfer: High pressure on the housing market and climate change adaption are not mutually exclusive. In a way, planning in cities is already an adaptation and a climate action measure. Let’s take the example of the City of Luxembourg. Luxembourg City accounts for about 2 % of the national territory and of this 2 % half are green areas, so forests, grassland, pastures or farmland. At the same time, about 20 % of the country’s population lives on the other 1 % and about 40 % of the national workplaces are located in the City of Luxembourg.

This results in density that offers proximity to daily activities such as workplaces or grocery shops, for inhabitants, reducing the need for transport. This helps us to offer much more targeted and effective measures.

The City of Luxembourg population has increased by more than 30 % during the past 10 years. This very high pressure is a challenge to urban planning in many ways. Increasing traffic, increasing pressure on the housing market, increasing pressure on public services, and so on. But despite this pressure, we have managed to make progress in achieving our environmental objectives, defined in the Municipal Environmental Report and Action Plans. This applies to the climate action measures, so to lower energy consumption or less municipal waste. This also applies to the adaptation measures, including the implementation of natural water retention systems or unsealing soil.

Of course, this does not come easily: when planning urban districts, we integrate environmental aspects in the conception plans from the very beginning. Therefore, it is important that the objectives and measures are clearly defined. This way, urban development and other urban functions can incorporate and work on environmental protection and climate change adaptation.

Mayor Lydie Polfer. Copyright: Maison Moderne – LaLa La Photo.

Interviewer: What is the role of the CIPU for climate change adaptation in Luxembourg?

Mayor Polfer: Urban development and planning is a complex and interrelated matter. When we develop plans, we usually touch on a variety of inter-connected disciplines, requiring us to work with various constrains and limitations. Sometimes urban planning meets disapproval from inhabitants and experts in related fields. Climate action and adaptation measures especially require planners to plan in a way that does not appear logical to the outside viewer.

CIPU should enhance mutual understanding and coordination between different policy fields, between planners and also between planners and inhabitants. This way, CIPU could be a mediator in the framework of urban development and for this year, focusing on climate change adaptation.

Interviewer: Thank you very much Mayor Polfer for the interview.

In case of questions or comments, please feel free to contact the editor (sebastian.hans@spatialforesight.eu) of this article.