FAQ

The provision relating to the super-reduced rate reduces the scope of application to the level of the type of building that will be equipped with solar panels, namely “on private housing, housing and building, public and others, used for activities of general interest, and in close proximity to these”.

As far as “private housing” is concerned, this is housing of which at least three quarters of the total surface area is reserved for living purposes. The same rule applies to housing and public buildings and others used for activities of general interest: at least three quarters of the total surface area must be reserved for these purposes.

A definition of this is provided in the grand-ducal regulation of 23 December 2022 amending: 1° the grand-ducal regulation amended on 21 December 1991 determining the limits and application conditions of the reduced, super-reduced and intermediate rates of value added tax; 2° […], and the following explication is provided by bulletin No 816 issued by the Registration Duties, Estates and VAT Authority: “private housing and buildings used by public authorities not subject to tax for activities carried out as such or used by those subject to tax for activities of general interest exempt from VAT without the right to deduct input tax (notably hospitals, schools, children’s nurseries, youth hostels and retirement homes)”. The provision of cultural services is added to the latest list.

The delivery and installation of photovoltaic solar panels close to housing or buildings referred to above does not interfere with the application for the super-reduced VAT rate of 3 % as long as the delivery and installation takes place on adjoining or separate properties but located close to private housing or housing and buildings, public and others, used for activities of general interest and as long as such photovoltaic solar panels are connected to the thermal and/or electrical network of the housing or buildings in question.

The grand-ducal regulation of 23 December 2022 amending: 1° the grand-ducal regulation amended on 21 December 1991 determining the limits and application conditions of the reduced, super-reduced and intermediate rates of value added tax; 2° […] defines in the context of the reduction of the VAT rate the “delivery and installation of solar panels” as follows: “work on a property consisting of the delivery of solar panels and their installation”.

As a result, all the parts necessary for this installation and its operation also come under the super-reduced rate, which implies the following parts of the photovoltaic solar panels: photovoltaic panels (or hybrid solar collectors), fixing rails, DC and AC electric cabling connected directly to the photovoltaic installation, inverter, electrical protection devices, bidirectional meter; and for the thermal solar panels: thermal solar collectors, fixing rails, insulated pipework, solar storage reservoir, calorimeter, peripheral equipment (power feed, regulation, heat exchangers); as well as, of course, the costs of installation.

For the photovoltaic solar panels, a storage installation (battery) is therefore not involved.

It is also important to note that the super-reduced rate only applies to such installation work on a solar power plant. Bulletin No 816 issued by the Registration Duties, Estates and VAT Authority defines this notion of “work on a property” as follows: “Therefore, there is reason for understanding this new provision not as the delivery of solar panels or the installation of such panels carried out separately, but as work on a property that consists of a delivery of solar panels with installation”.

Applications for obtaining financial aid must be submitted no later than 12 months after the last invoice was issued in connection with the investment.

Regular maintenance of a rendered façade can considerably reduce the risk of algal growth and fungal attack. Façades most at risk (north-facing and shaded façades) must be cleaned regularly by a specialist company and painted if necessary. Damaged connection and expansion joints on window sills and air outlets of ventilation systems should be renewed.

In the case of composite thermal insulation systems, the choice of material and the application of the coating can delay the formation of algae. The following materials should be preferred:

• mineral renders;
• thick renders;
• renders without the addition of colour, which require a coat of paint after application;
• smooth-textured finishing renders.

Many renders contain biocides (pesticides) that are supposed to prevent the growth of algae and fungi, but over time these biocides are washed off by rain and end up in waterways and soils. Mineral renders are an environmentally friendly alternative to renders containing biocides.

Heavy insulating materials (with high bulk density) store heat better than light insulating materials. During short periods of low temperature, the façade cools down more slowly and less condensation forms on the rendered surface, which reduces the risk of algal and fungal growth.

Heavy insulating materials are generally made of renewable raw materials: wood fibres, cellulose, hemp, etc. The Luxembourg aid scheme Klimabonus provides for a specific category for insulation materials made from renewable, environmentally friendly raw materials with a higher subsidy.

In general, ventilated curtain walls and monolithic structures without a composite thermal insulation system are less vulnerable to algal and fungal growth.

Eaves and window sills as well as the substructural areas protect façades from rain and water splashes and thus reduce the risk of algal and fungal growth. This constructive protection against moisture is part of the architectural design and must be taken into account in the design phase.

Algal or fungal growth on façades is caused by moisture from rain or condensation on the rendered surface not evaporating quickly enough. The higher the humidity of the outside air and the lower the temperature of the rendered surface, the higher the condensation level. The humidity lasts for a particularly long time on the sides less exposed to the sun (north and west) and when trees or plants cast shade on the façade.

The growth of algae and fungi is favoured by the absence of protection against rainwater, such as eaves or a window sill, or against water splashes at substructure level.

Algae and fungi can form on both insulated and non-insulated façades. As a rule, thin-layer exterior renderings on insulated façades and coarse-textured façades are more vulnerable to algal growth. On the other hand, mineral coatings covered with a suitable paint are less vulnerable.