Who is this guide for?

This guide is intended for homeowners, property owners, co-ownerships and small businesses in Luxembourg considering a photovoltaic installation and wanting to understand the steps before starting the work.

Before the quote: the first points to check

The first step is to check whether the project makes technical sense. Two homes located in the same municipality can deliver very different results depending on roof orientation, shading, available surface area, roof condition and consumption profile.

This step makes it possible to build a useful solar quote, not just a price. A good quote should explain the proposed capacity, the choice of panels, the inverter, electrical protections, the self-consumption logic and future upgrade possibilities.

Also read: points to check before signing a solar quote and sizing a photovoltaic installation in Luxembourg.

Municipal authorization: why you should check before the work begins

In Luxembourg, it is important to remain cautious about authorizations. According to Guichet.lu, for each type of installation, you should check with the municipal administration of the building’s location whether a building permit is required or not.

You should therefore not assume that one single answer applies across the whole country. Some municipalities may have specific requirements, especially depending on the type of building, visibility from public space, protected areas or local planning rules.

Grid connection: what is the request for?

A photovoltaic installation connected to the grid must be technically validated by the competent grid operator. This step is used to check that the project is complete, technically feasible and compliant with connection requirements.

For customers connected to the Creos grid, the request is made through the myCreos customer area. Klima Agence indicates that, for self-consumption, the request is made under “Easy Grid Connect”. In other areas, the operator may be the City of Diekirch, the City of Ettelbruck or Sudstroum.

Creos recommends completing the online request with the electrician. Depending on the case, the electrician may also submit the request on behalf of the customer. This is an important point: even if the owner remains involved in the project, technical support often helps avoid file errors.

At Ecoclima, we support you through all these steps.

Self-consumption, surplus or full injection: how to choose?

The operating mode should be chosen in line with your real consumption. The goal is not simply to produce as much as possible, but to produce useful energy that is properly valued and suited to your home.

Mode	Principle	To consider if…
Self-consumption	You consume part of your solar production on site.	You have daytime consumption, a heat pump, an electric vehicle or a battery project.
Self-consumption with surplus	You consume part of the electricity and inject the excess into the grid.	You want to optimize the use of your production while valuing the surplus you do not consume.
Full injection	The production is injected into the grid instead of being consumed directly on site.	Your main goal is selling the production, depending on the conditions applicable to the project.

For self-consumption, Klima Agence indicates that the request to operate the installation in self-consumption mode must be communicated to the grid operator. To sell surplus electricity, a buyback contract must also be concluded with an electricity supplier.

During the work: what needs to be coordinated

Installing solar panels is not limited to mounting modules on the roof. A reliable installation must coordinate the roof work, electrical work, protections, connection, inverter, monitoring and grid operator requirements.

This is also when execution quality matters most. A well-installed project should be clean, documented and designed to last. This concerns solar production as much as electrical safety and future maintenance.

After installation: commissioning, buyback contract and follow-up

Once the panels are installed, the project is not finished. Documents, commissioning authorizations, possible checks and procedures related to injection or self-consumption still need to be finalized.

Creos indicates that, depending on the configuration, commissioning takes place after the required documents have been received. The electrician must also complete the work completion notice through the dedicated application. The grid operator can then check the work and request an inspection if necessary.

What about photovoltaic prefinancing?

Photovoltaic prefinancing is separate from grid procedures. The principle is simple: when the conditions are met, the Klimabonus subsidy can be deducted directly from the final invoice by an installer registered in the list of installers admitted to the procedure.

This is not a reason to neglect the technical steps. Guichet.lu specifies in particular that the prefinancing request involves documents such as the final invoice, the work completion declaration sent to the competent grid operator and the co-signed customer agreement.

Also read: photovoltaic prefinancing in Luxembourg.

What Ecoclima can handle in your project

An installer’s role should not be limited to installing panels. For a photovoltaic project in Luxembourg, support should help the customer understand the steps, prepare the right technical documents and coordinate the required interventions.

Step	Your role	Possible support
Project study	Share your bills, consumption habits and goals.	Analysis of the roof, solar potential, relevant capacity and suitable equipment.
Municipality	Check the applicable requirements with your municipality if necessary.	Provision of useful technical information to make the exchange easier.
Connection	Validate the requested information and documents.	Preparation or support for the request with the electrician depending on the case.
Work	Provide access to the building and validate the schedule.	Installation, electrical connection, protections, configuration and finishing.
After installation	Keep the documents and monitor production.	Commissioning, technical follow-up, usage advice and self-consumption optimization.

Mistakes to avoid before starting the work

• Signing a quote without understanding the operating mode: self-consumption, surplus or full injection.
• Forgetting to check municipal requirements before installation.
• Choosing only the lowest price without looking at electrical protections, equipment and follow-up.
• Oversizing the installation without linking it to real consumption.
• Not anticipating a future battery, charging station or heat pump.
• Neglecting completion documents, which are useful for subsidies, follow-up and future resale of the property.

FAQ: solar panel procedures in Luxembourg