FAQ

When windows are not properly sealed, it leads to insufficient and unreliable ventilation and generally prevents correct ventilation in a dwelling. Adequate ventilation is achieved by opening windows or using a comfort ventilation system (CMV). On the other hand, windows that are not tightly sealed cause heat loss and draughts on cold days. These factors thus combine to create an unpleasant indoor climate and unnecessarily high heating costs.  

In you are retrofitting, it is advisable to have the new windows installed by a specialist, who will take care to remove any existing thermal bridges.

Mould growth is associated with elevated humidity levels and insufficient ventilation rather than with good insulation practice.

Indeed, the reverse is true: improved insulation quality prevents the formation of mould. This is found to be the case in many energy-efficient homes and buildings that have been retrofitted for energy efficiency. They are perfectly insulated, airtight and completely free of mould. If the external walls are not satisfactorily insulated, air moisture condenses in the cold areas, which favours the formation of mould. Effective thermal insulation of the façade tends to raise the surface temperature of the external wall and thus prevent moisture from accumulating.

It is likewise important to identify and eliminate all thermal bridges in the building (i.e. places where there are gaps in the insulation). Such bridges can be found, among other places, in recesses for radiators or on balconies. In addition, it is not advisable to place furniture in front of external walls, as this prevents the indoor air from circulating freely, meaning that the surfaces behind the furniture cool down.  
 

Benefit from financial support of up to 50% of the investment cost!

Under Article 4(h) of the Law of 31 May 1999, as amended, establishing a fund for the protection of the environmental, municipal administrations, municipal associations and public bodies under the supervision of the municipalities may receive aid covering up to 50% of the investment cost for projects for the rational use of energy and the promotion of new and renewable energy sources. This financial aid is accessible to all municipalities, regardless of their commitment to the climate pact.

The Ministry of the Economy regularly checks the calculations. The experts concerned can therefore be reported to the Ministry of the Economy or to Klima-Agence.

The Ministry of the Economy regularly publishes a list of approved experts who have undergone specific training: www.guichet.lu/experts-energie.

In addition, it is also possible to obtain a list of approved experts from the OAI. If in doubt about an expert's accreditation, you can ask for their accreditation documents or contact the Ministry of the Economy.

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.

The deviations must be documented and the main contractor must be notified of them. The municipality has the right to request additional calculations and/or documentation. The "as built” EPC indicates whether the minimum requirements have been met despite the deviations once the building is completed. As with any non-compliance with the building permit, the municipality can demand that the construction work required to ensure compliance with the EPC be carried out during the construction period and call the police if necessary.

It is not mandatory to carry out inspections of building sites. However, the municipality has the right to go to the building site and check the construction work to check that it complies with the energy performance certificate.

The municipality has the right to request the "as built" EPC from the main contractor. Other measures may also be envisaged, for example the introduction of a deposit system. According to one Grand Ducal Regulation, municipalities even have the possibility of prosecuting the main contractor (sanctions enshrined in the Law of 5 August 1993 on the rational use of energy, as amended).