Photovoltaic systems: Ground vs. roof - How to make the best choice?

Photovoltaic systems: how to choose between ground and roof?

Faced with the energy transition and steadily rising electricity prices, many private individuals and professionals are turning to solar energy to generate their own electricity. However, a crucial question arises right from the start of the project: should the photovoltaic system be ground-mounted or roof-mounted? This decisive choice will influence not only the performance of your installation, but also its cost, its integration into the landscape and its durability.

At Wattuneed, a specialist in renewable energy equipment, we work with our customers on a daily basis to help them make the right choice. Our experience has taught us that every situation is unique and deserves a personalized analysis.

Rooftop photovoltaic systems: the most widespread option

The installation of rooftop solar panels is currently the preferred solution for most private individuals and many businesses. This popularity is due to a number of considerable advantages.

Advantages of rooftop installations

• Optimization of available space: Roofs are often unused surfaces that can be put to good use without impacting on land use.
• Administrative simplification: In many cases, administrative procedures are simpler than for ground-mounted installations, particularly in terms of town planning.
• Protection against vandalism: Their elevated position makes them less accessible and therefore less vulnerable to deliberate damage.
• Landscape impact: Often less visible from the ground, they generally blend in better with the surrounding landscape.

Technical criteria for optimum rooftop installation

To maximize the performance of a rooftop installation, several factors need to be taken into account:

• Orientation: Ideally south-facing, with an acceptable east-west tolerance at a slight loss of yield.
• Tilt: The optimum angle is generally between 30° and 35° in our latitudes, but adapting to the existing roof pitch is often the most economical.
• Absence of shading: Any obstacle casting a shadow (chimney, tree, neighbouring building) can significantly reduce production.
• Roof structure and age: The load-bearing capacity of the roof and its general condition must be assessed to ensure the long-term safety of the installation.

"After installing 16 panels on our southwest-facing roof, our electricity bill fell by 70%. Visual integration is perfect and we haven't lost any useful space in our garden."

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Bernard family, Liège

To assess whether your roof is suitable for solar panel installation, contact our experts who can carry out a personalized study of your situation.

Constraints and limitations of rooftop installations

Despite their many advantages, rooftop installations present certain constraints:

• Complexity of installation: Working at height requires specific safety measures and increases the technical difficulty of installation.
• Imposed configuration: You have to deal with the existing orientation and inclination of your roof, which are sometimes not optimal.
• Surface limitations: The size of the installation is restricted by the dimensions of your roof.
• Waterproofing issues: A poorly installed system can compromise the waterproofing of the roof.

Ground-mounted photovoltaic systems: a powerful alternative

Ground-mounted photovoltaic systems are less common among private customers, but are very popular in the agricultural and industrial sectors. They are an interesting alternative when conditions are right.

Advantages of ground-mounted systems

• Total optimization of orientation and inclination: Unlike roofs, panels can be perfectly positioned to maximize yield.
• Ease of maintenance: Simplified access allows regular cleaning and easier technical intervention.
• Scalability: It's generally easier to expand a ground-mounted system as energy needs change.
• Natural cooling: Air circulation around the panels improves their efficiency, particularly in hot weather.

Innovative technologies for ground-mounted systems

Ground-mounted systems benefit from specific technologies to optimize their performance:

• Tracking systems: These devices enable the panels to follow the path of the sun throughout the day, increasing production by up to 30% depending on the model.
• Bifacial structures: The panels capture light from both sides, also taking advantage of the radiation reflected by the ground.
• Agrivoltaic solutions: Combining agricultural production and solar energy, these systems make double use of the land.

"As a farmer, I installed a 100 kWp ground-mounted power plant on a plot of land with low fertility. The tracking system allows me to produce 15% more electricity than a fixed installation, while still allowing me to graze my sheep under the panels."

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Mr. Dupont, farmer in the Namur region

Discover our complete range of equipment for ground-mounted photovoltaic installations, including innovative structures adapted to all types of terrain.

Constraints specific to ground-mounted installations

Ground-mounted photovoltaic projects face a number of important limitations:

• Sufficient land available:
• A ground-mounted installation consumes space that cannot be used for other activities (except in the case of agrivoltaics).
• More complex administrative procedures:
• Depending on size and location, a building permit is generally required.
• Greater landscape impact: Visible in the surrounding environment, the installation may arouse opposition from neighbors.
• Increased risk of vandalism: Their accessibility makes them more vulnerable, sometimes requiring additional security measures.

Comparative analysis: ground versus roof

To help you make the best choice for your situation, here's a detailed comparative table of the two solutions:

Economic analysis of photovoltaic systems

Installation costs and return on investment

The cost of a photovoltaic installation varies significantly according to its type and size. In 2025, the following trends can be observed:

• Roof-mounted: Between €1,500 and €2,200/kWp for a complete installation, including panels, inverters, fastenings and labor.
• Ground-mounted: Between €1,300 and €1,800/kWp, generally less expensive per kWp for larger powers thanks to economies of scale.

Payback time depends on a number of factors:

• The initial cost of the installation
• Annual production (influenced by orientation, inclination and geographical location)
• The price of electricity and its foreseeable evolution
• Current support mechanisms (premiums, feed-in tariffs, green certificates)

Case study with figures

Case 1: Residential rooftop installation

• Installed capacity: 6 kWp
• Total cost: €12,000 (after deduction of subsidies)
• Annual production: 5,400 kWh/year
• Annual savings/income: €1,200/year
• Return on investment: 10 years

Case 2: Professional ground-mounted system

• Installed capacity: 100 kWp
• Total cost: €130,000 (after deduction of subsidies)
• Annual production: 105,000 kWh/year
• Annual savings/income: €15,750/year
• Return on investment: 8.5 years

Use our profitability simulator to accurately assess the economic potential of your photovoltaic project.

Recommendations according to your profile

For private customers

Owners of single-family homes generally prefer roof-mounted systems for a number of reasons:

• Limited space available on the ground
• Enhancement of an already-built surface
• Aesthetic integration with the building
• Simplified administrative procedures

Recommendation: If your roof faces south-east to south-west, with a slope of between 20° and 45° and no significant shading, a roof-mounted system is often the ideal solution.

For farmers

The agricultural sector generally has two viable options:

• Large hangar roofs: large surfaces often well oriented and easily exploitable
• Ground-mounted installations: valorization of less productive land with the possibility of agrivoltaics

Recommendation: For farms with less fertile land or land that is difficult to cultivate, ground-mounted systems with tracking systems represent a particularly interesting opportunity to diversify income.

For business and industry

Companies can consider different approaches depending on their real estate situation:

• Roofs of industrial or commercial buildings: Generally flat and large in area, ideal for maximizing installed power
• Car park canopies: An intermediate solution for making the most of parking spaces
• Ground-mounted power plants: For companies with unused land

Recommendation: Companies should opt for a self-consumption approach, with sizing adapted to their consumption profile, potentially combining different solutions to maximize the self-generation rate.

Legal framework and financial support

In France

The French regulatory framework clearly distinguishes between two types of installation:

• Rooftop installations: A simple declaration of works is generally sufficient for installations of less than 3 kWp. Beyond that, the process can become more complex, depending on the municipality and the location.
• Ground-mounted installations: Planning permission is required for any ground-mounted installation whose output exceeds 3 kWp or whose height exceeds 1.80 m.

The main subsidies available in 2025 include

• Self-consumption bonus (up to €380/kWp)
• Reduced VAT of 10% for installations under 3 kWp
• Subsidized feed-in tariff for electricity fed into the grid

In Belgium

The Belgian framework has some important regional specificities:

• In Wallonia: The green certificate mechanism remains in force, with gradual changes to the metering system.
• In Flanders: The compensation system has been replaced by the prosumer tariff and installation bonuses.
• In Brussels: Specific bonuses are available depending on the category of applicant.

For ground-mounted installations, planning permission is generally required, with varying conditions depending on the municipality and the area concerned.

Care and maintenance: key factors in sustainability

Maintenance of rooftop installations

Roof-mounted systems require specific maintenance:

• Cleaning: Less frequent thanks to the slope, which favors self-cleaning by rain, but more complex to carry out
• Structural inspection: Periodic check of fixings and waterproofing
• Electrical inspection: Annual check of connections and performance to detect any anomalies

Average annual maintenance cost: €15 to €25/kWp

Maintenance of ground-mounted systems

Ground-mounted systems have different requirements:

• Cleaning: More frequent because the panels are more exposed to dust and dirt, but easier to carry out
• Grounds maintenance: Regular mowing of vegetation to avoid shading and facilitate access
• Maintenance of mechanical systems: In the case of trackers, maintenance of moving parts

Average annual maintenance cost: €20-30/kWp

To guarantee your system's optimum performance over the long term, find out more about our preventive maintenance contracts for all types of photovoltaic systems.

Frequently asked questions

Do I need planning permission for a photovoltaic system?

In France, for roof-mounted systems, a simple declaration of works is generally sufficient for systems of less than 3 kWp. For ground-mounted installations, planning permission is required if the power exceeds 3 kWp or the height exceeds 1.80 m. In Belgium, rules vary from region to region, but planning permission is generally required for ground-mounted installations, while roof-mounted installations may sometimes be exempt, depending on their integration.

What financial assistance is available for installing solar panels?

Financial assistance varies from country to country and region to region. In France, there's the self-consumption bonus, reduced VAT and subsidized feed-in tariffs. In Belgium, the system differs by region, with green certificates in Wallonia and specific bonuses in Flanders and Brussels. In both countries, low-interest loans are also available to finance these installations.

What is the average lifespan of a photovoltaic system?

The average lifespan of photovoltaic panels is 25 to 30 years, with a degradation in performance of around 0.5% per year. Inverters generally have a shorter lifespan, between 10 and 15 years, requiring replacement during the life of the installation. Mounting structures, whether ground- or roof-mounted, are designed to last at least 25 years under normal conditions of use.

How do I choose between ground-mounted and roof-mounted if I have both options?

If you have the option of installing solar panels both on the ground and on your roof, several factors should guide your choice: the orientation and inclination of your roof (if they are close to optimal, roofing may be preferable), the surface area available in relation to your energy needs, local planning constraints, and the use you intend to make of the land (if it has other potential uses, give preference to roofing). A personalized technical-economic analysis is often necessary to determine the most cost-effective solution for your specific situation.

Are photovoltaic systems weatherproof?

Modern photovoltaic systems are designed to withstand extreme weather conditions, including hail, snow and strong winds. Panels are tested to withstand significant hail impacts and heavy snow loads. Mounting structures, both ground and roof-mounted, are calculated according to current standards to withstand the prevailing winds of each region. However, it is important to ensure that installation is carried out by qualified professionals who scrupulously respect these standards to guarantee this resistance over the long term.

Conclusion: make the right choice for your situation

The choice between a ground-mounted or roof-mounted photovoltaic system depends on many personal and contextual factors. There is no universally better solution, but rather configurations more suited to each particular case.

For individuals with a well-oriented roof, a roof-mounted system is generally the most practical and economical solution. For professionals with high energy requirements and available land, ground-mounted installations can offer better energy optimization and easier maintenance.

In all cases, a personalized study that takes into account all technical, economic and regulatory parameters is essential to make the most appropriate choice.

Wattuneed's experts are at your disposal to help you make the right choice and offer you the photovoltaic solution best suited to your specific needs.

Contact us

Wattuneed
Rue Henripré 12
4821 Andrimont
Belgium
+32 87 45 00 34
info@wattuneed.com