PVGIS Rooftop Nantes: Solar Calculator in Loire Valley Region

The Solar Potential of Nantes and the Loire Valley

Balanced Sunshine

Nantes displays an average yield of 1150-1200 kWh/kWp/year, positioning the region in the upper third of French cities for solar energy. A residential 3 kWp installation generates 3450-3600 kWh per year, covering 65-85% of a household's needs depending on the consumption profile.

Strategic geographic position: Located at the confluence of the Loire and near the Atlantic, Nantes benefits from a temperate climate without the thermal extremes of other regions. This mild climate promotes optimal photovoltaic panel performance.

Regional comparison: Nantes produces 10-15% more than Paris , 5-8% more than Rennes and Lorient , and positions favorably compared to major northern and eastern metropolitan areas. An excellent compromise between sunshine and climate comfort.

Loire Valley Climate Characteristics

Oceanic mildness: The Nantes climate is characterized by moderate temperatures year-round. Photovoltaic panels thrive in these conditions: no extreme heat waves (which reduce efficiency), no significant snow (which interrupts production).

Regular production: Unlike the Mediterranean south where production is highly concentrated in summer, Nantes maintains more balanced production throughout the year. The gap between summer and winter is 1 to 3 (versus 1 to 4 in the South), facilitating annual self-consumption.

Atlantic luminosity: Even in overcast conditions (frequent in Nantes), diffuse radiation allows for non-negligible production. Modern panels efficiently capture this indirect light, characteristic of the oceanic climate.

Productive transitional seasons: Spring and autumn in Nantes are particularly favorable with 280-350 kWh monthly for a 3 kWp installation. These extended periods compensate for less intense summer production than in the south.

Calculate your solar production in Nantes

Configuring PVGIS for Your Nantes Rooftop

Loire Valley Climate Data

PVGIS integrates over 20 years of meteorological history for the Nantes region, capturing the specificities of the Loire Valley climate:

Annual irradiation: 1250-1300 kWh/m²/year on average, placing the Loire Valley in a favorable position for photovoltaic development.

Regional homogeneity: The Loire Valley presents relatively uniform sunshine. Differences between Nantes, Angers, La Roche-sur-Yon, or Le Mans remain modest (±3-5%), facilitating estimation for the entire region.

Typical monthly production (3 kWp installation):

• Summer (June-August): 420-480 kWh/month
• Spring/Autumn (March-May, Sept-Oct): 280-360 kWh/month
• Winter (Nov-Feb): 140-180 kWh/month

This balanced distribution is a major asset for self-consumption: useful production year-round rather than concentrated over 3 summer months.

Optimal Parameters for Nantes

Orientation: In Nantes, south-facing orientation remains optimal. However, southeast or southwest orientations retain 90-94% of maximum production, offering great flexibility to adapt to architectural constraints.

Adaptation to oceanic climate: A slightly southwest orientation (azimuth 200-220°) can be interesting to capture the afternoon clearings frequent in the Atlantic climate. PVGIS allows you to simulate these options.

Tilt: The optimal angle in Nantes is 33-35° to maximize annual production. Traditional Loire Valley roofs (slates, 35-45° pitch) are slightly above optimal, but the loss remains minimal (2-3%).

For low-pitch or flat roofs (Nantes industrial buildings, business zones), favor 20-25° to limit wind load while maintaining good production.

Adapted technologies: Standard monocrystalline panels (19-21% efficiency) are perfectly suited to the Nantes climate. Technologies that better capture diffuse radiation (PERC) can provide a slight gain (+2-3%) interesting for maximizing production in cloudy weather.

Integrating System Losses

The standard PVGIS loss rate of 14% is relevant for Nantes. This rate includes:

• Wiring losses: 2-3%
• Inverter efficiency: 3-5%
• Soiling: 2-3% (frequent Nantes rains ensure effective natural cleaning)
• Thermal losses: 4-6% (moderate temperatures = limited thermal losses)

For well-designed installations with premium equipment, you can adjust to 12-13%. The Nantes climate preserves equipment with little thermal stress.

Nantes Architecture and Photovoltaics

Traditional Loire Valley Housing

Tuffeau stone houses: Typical Nantes and Angers architecture features natural slate roofs, 40-45° pitch. Available surface: 30-50 m² allowing 5-8 kWp installation. Panel integration on slate is aesthetic and preserves regional character.

City center townhouses: The historic center of Nantes (Bouffay, Feydeau Island) has beautiful 18th-19th century residences with vast roofs. Architectural constraints to respect but opportunities for condominium installations.

Suburban houses: The Nantes ring (Rezé, Saint-Herblain, Vertou, Carquefou) concentrates recent developments with optimized roofs of 25-40 m². Typical production: 3450-4800 kWh/year for 3-4 kWp installed.

Business Zones and Industry

Aeronautical hub (Saint-Nazaire, Bouguenais): Airbus and its subcontractors occupy buildings with vast industrial roofs (500-5000 m²). Considerable potential for 75-750 kWp installations.

Commercial zones: Nantes has numerous business areas (Atlantis, Beaujoire, Carquois) with shopping centers and warehouses offering flat roofs ideal for solar.

Port of Nantes: Port and logistics facilities present exceptional surfaces for large-scale photovoltaic projects.

Urban Planning Constraints

Protected area: Nantes' historic center (Bouffay, Graslin) is protected. The Architecte des Bâtiments de France (ABF) must validate projects. Favor discreet building-integrated panels.

Île de Nantes: This district undergoing major urban renovation systematically integrates renewable energies into new projects. Constraints are less strict than in the historic center.

Condominium regulations: As in any metropolitan area, check your condominium rules before installation. Attitudes are evolving favorably with environmental awareness.

Nantes Case Studies

Case 1: Single-Family Home in Vertou

Context: 2010s house, family of 4, partial remote work, self-consumption goal.

Configuration:

• Surface: 26 m²
• Power: 3.6 kWp (10 x 360 Wp panels)
• Orientation: South-Southeast (azimuth 165°)
• Tilt: 35° (slate)

PVGIS simulation:

• Annual production: 4180 kWh
• Specific yield: 1161 kWh/kWp
• Summer production: 540 kWh in July
• Winter production: 190 kWh in December

Profitability:

• Investment: €8,900 (after self-consumption bonus)
• Self-consumption: 56% (remote work 2 days/week)
• Annual savings: €560
• Surplus sale: +€190
• Return on investment: 11.9 years
• 25-year gain: €10,800

Lesson: The Nantes periphery offers good conditions with little shading. Growing remote work in the metropolitan area (developed tertiary sector) significantly improves self-consumption.

Case 2: Tertiary Business on Île de Nantes

Context: Digital sector offices, high daytime consumption, recent eco-designed building.

Configuration:

• Surface: 300 m² roof terrace
• Power: 54 kWp
• Orientation: Due south (25° frame)
• Tilt: 25° (production/aesthetics compromise)

PVGIS simulation:

• Annual production: 62,000 kWh
• Specific yield: 1148 kWh/kWp
• Self-consumption rate: 86% (continuous daytime activity)

Profitability:

• Investment: €81,000
• Self-consumption: 53,300 kWh at €0.18/kWh
• Annual savings: €9,600 + resale €1,400
• Return on investment: 7.4 years
• "Eco-responsible company" label (communication)

Lesson: The Nantes tertiary sector (IT, services, consulting) presents an ideal profile with daytime consumption. Île de Nantes, a modern business district, concentrates these opportunities. Companies integrate photovoltaics into their CSR strategy.

Case 3: Agricultural GAEC in Vendée (Near Nantes)

Context: Dairy farm with agricultural building, significant consumption (milking, cooling, ventilation).

Configuration:

• Surface: 200 m² fiber cement roof
• Power: 36 kWp
• Orientation: Southeast (morning production for milking)
• Tilt: 12° (existing low-pitch roof)

PVGIS simulation:

• Annual production: 40,300 kWh
• Specific yield: 1119 kWh/kWp (slight tilt loss)
• Self-consumption rate: 82% (continuous farm consumption)

Profitability:

• Investment: €54,000
• Self-consumption: 33,000 kWh at €0.16/kWh
• Annual savings: €5,300 + resale €950
• Return on investment: 8.6 years
• Environmental enhancement of operation

Lesson: The Loire Valley, the leading agricultural region in western France, offers excellent photovoltaic opportunities. Dairy farms with continuous cooling present an ideal profile for self-consumption.

Self-Consumption in Nantes

Loire Valley Consumption Profiles

The Nantes lifestyle directly influences self-consumption opportunities:

Developed remote work: Nantes, a dynamic tertiary metropolitan area (IT, consulting, services), experiences strong remote work development. Daytime presence increases self-consumption from 40% to 55-65%.

Widespread electric heating: As in western France, electric heating is common in Nantes. Air-to-water heat pumps are developing. Transitional season solar production (March-May, Sept-Oct) can cover part of moderate heating needs.

Limited air conditioning: Unlike the south, air conditioning remains marginal in Nantes (mild summers). Summer consumption therefore remains mainly appliances, lighting, IT. Advantage: no summer overconsumption, but potentially lower self-consumption than in the south.

Electric water heater: Standard in Loire Valley housing. Switching heating to daytime hours (instead of nighttime off-peak hours) allows self-consumption of an additional 300-500 kWh per year.

Optimization for the Loire Valley Climate

Smart programming: With approximately 160-180 sunny days, programming energy-intensive equipment (washing machine, dishwasher, dryer) during the day (11am-3pm) is effective in Nantes.

Electric vehicle: Nantes actively develops electric mobility (electric TAN network, numerous charging stations, car sharing). Solar charging of an EV absorbs 2000-3000 kWh/year, optimizing self-consumption.

Managing cloudy days: Even in overcast conditions, panels produce 15-35% of their capacity. This "residual" production covers basic consumption (refrigerator, internet box, standby) and can partially power scheduled equipment.

Transitional season heating: For heat pumps, solar production in April-May and September-October (300-350 kWh/month) can cover part of mild transitional heating needs, a period when the heat pump consumes moderately.

Realistic Self-Consumption Rate

Without optimization: 35-45% for household absent during the day With programming: 50-60% (equipment, water heater) With remote work: 55-65% (increased daytime presence) With electric vehicle: 60-70% (daytime charging absorbing surplus) With battery: 75-85% (investment +€6,000-8,000)

In Nantes, a self-consumption rate of 50-60% is realistic with moderate optimization, without major investment. The balanced climate promotes regular consumption aligned with production.

Local Dynamics and Energy Transition

Nantes, Pioneer City

Nantes positions itself as a pioneer city in energy transition in France:

Climate Plan: The metropolitan area aims for carbon neutrality by 2050 with ambitious renewable energy development objectives.

Third places and coworking: Numerous shared spaces integrating photovoltaics in their design. These places raise awareness among entrepreneurs and freelancers about renewable energies.

Sustainable neighborhoods: Île de Nantes, Dervallières, Bottière develop eco-districts with systematic photovoltaics on new buildings.

Citizen awareness: The Nantes population shows strong environmental sensitivity (significant ecological voting, active associations). This culture facilitates solar acceptance and development.

Loire Valley Agricultural Sector

The Loire Valley, the leading agricultural region in western France, offers considerable photovoltaic potential:

Dairy farming: Significant electricity consumption (robotic milking, milk cooling), continuous operation. Ideal profile for self-consumption (80-90%).

Market gardening: The Nantes region has numerous market gardening operations. Heated greenhouses consume massively, but out of sync with solar production. Storage solutions or cogeneration to study.

Viticulture: The Nantes vineyard (Muscadet) develops photovoltaics on wine cellars and buildings. Moderate consumption but valuable environmental image.

Specific aid: The Loire Valley Chamber of Agriculture supports farmers in their photovoltaic projects with technical advice and financial structuring.

Choosing an Installer in Nantes

Structured Regional Market

Nantes and the Loire Valley concentrate numerous qualified installers, creating a mature market with diverse offerings and competitive prices.

Selection Criteria

RGE certification: Mandatory for national aid. Verify on France Rénov' that the certification is valid and covers photovoltaics.

Local experience: An installer familiar with the Loire Valley climate knows the specificities: frequent rains (natural cleaning but anti-corrosion structures), Atlantic winds (adapted sizing), local regulations.

Verifiable references: Request recent installations in your area (Nantes center, periphery, rural areas). Contact former clients if possible for feedback.

Consistent PVGIS estimate: In Nantes, a yield of 1120-1200 kWh/kWp is realistic. Beware of announcements >1250 kWh/kWp (overestimation) or <1100 kWh/kWp (too conservative).

Quality equipment:

• Panels: recognized Tier 1 brands, 25-year production warranty
• Inverter: reliable European brands, 10+ year warranty
• Structure: corrosion resistance (ocean proximity), wind sizing

Complete warranties:

• Valid ten-year liability (request certificate)
• Workmanship warranty: 2-5 years minimum
• Responsive local after-sales service (important for quick intervention if needed)

Nantes Market Prices

Residential (3-9 kWp): €2,000-2,600/kWp installed SME/Tertiary (10-50 kWp): €1,500-2,000/kWp Agricultural/Industrial (>50 kWp): €1,200-1,600/kWp

Competitive prices thanks to a mature market and high installer density. Slightly lower than Paris, comparable to other regional metropolitan areas.

Points of Vigilance

Certification verification: Some companies present themselves as "RGE partners" without being certified themselves. Require direct certification of the company performing the work.

Detailed quote: The quote must specify all items (equipment, installation, administrative procedures, connection, commissioning). Beware of "all-inclusive" quotes without detail.

Production commitment: Some serious installers offer a guarantee on PVGIS yield (performance commitment). This is a sign of professionalism and confidence in their sizing.

Financial Aid in Loire Valley

2025 National Aid

Self-consumption bonus (paid year 1):

• ≤ 3 kWp: €300/kWp or €900
• ≤ 9 kWp: €230/kWp or €2,070 max
• ≤ 36 kWp: €200/kWp

EDF OA purchase tariff: €0.13/kWh for surplus (≤9kWp), guaranteed 20-year contract.

Reduced VAT: 10% for installations ≤3kWp on buildings >2 years old (20% beyond).

Loire Valley Regional Aid

The Loire Valley Region actively supports energy transition:

Renewable energy program: Additional aid for individuals and professionals (variable amounts according to annual budget, typically €300-600).

Overall renovation bonus: If photovoltaics are part of an overall energy renovation project (insulation, heating), increased aid is available.

Agricultural support: Specific aid via the Chamber of Agriculture for agricultural operations integrating photovoltaics.

Consult the Loire Valley Region website or France Rénov' Nantes for current programs.

Nantes Metropolitan Aid

Nantes Métropole (24 municipalities) offers:

• Occasional subsidies for energy renovation
• "Nantes en transition" program with technical support
• Bonus for innovative projects (collective self-consumption, electric mobility coupling)

Contact the Nantes Métropole Energy Information Center (free service).

Complete Financing Example

3.6 kWp installation in Nantes:

• Gross cost: €8,500
• Self-consumption bonus: -€1,080 (3.6 kWp × €300)
• Loire Valley Region aid: -€400 (if eligible)
• CEE: -€280
• Net cost: €6,740
• Annual production: 4,180 kWh
• 56% self-consumption: 2,340 kWh saved at €0.20
• Savings: €470/year + surplus sale €240/year
• ROI: 9.5 years

Over 25 years, the net gain exceeds €11,000, excellent return for western France.

Frequently Asked Questions - Solar in Nantes

Does Nantes have enough sun for photovoltaics?

Yes! With 1150-1200 kWh/kWp/year, Nantes ranks favorably among French cities. Production is 10-15% higher than Paris and comparable to other western metropolitan areas. The mild climate even optimizes panel efficiency (no summer overheating).

Isn't frequent rain a problem?

On the contrary, it's an advantage! Nantes rains ensure natural panel cleaning, limiting dust accumulation and maintaining optimal efficiency. Even in overcast conditions, panels produce thanks to diffuse radiation.

Do panels resist the oceanic climate?

Yes, modern panels are designed to resist humidity and weather. Use anti-corrosion materials (aluminum or stainless steel structures) for ocean proximity. A serious installer knows these requirements.

What production in Nantes winter?

Nantes maintains decent winter production: 140-180 kWh/month for 3 kWp. That's 10-20% more than Paris in winter thanks to mild temperatures and frequent clearings. Continuous rainy days are actually quite rare.

Do photovoltaics work with a heat pump?

Yes, excellent synergy! In transitional seasons (April-May, Sept-Oct), solar production (300-350 kWh/month) can partially cover mild heating needs of the heat pump. In summer, the heat pump consumes almost nothing. Size for spring/autumn self-consumption.

What lifespan in Loire Valley climate?

25-30 years for panels (25-year warranty), 10-15 years for inverter. The mild Nantes climate, without thermal extremes, preserves equipment longevity. Loire Valley installations age very well with little material stress.

Professional Tools for Loire Valley

For installers, design offices, and developers operating in Nantes and the Loire Valley region, advanced features quickly become necessary:

PVGIS24 brings real added value:

Simulations adapted to oceanic climate: Model specific consumption profiles (electric heating, heat pump, remote work) to precisely size according to Loire Valley climate.

Personalized financial analyses: Integrate Loire Valley regional aid, local specificities (electricity prices, consumption profile), for ROI calculations adapted to each Nantes client.

Portfolio management: For Loire Valley installers handling 40-70 annual projects, PVGIS24 PRO (€299/year, 300 credits, 2 users) represents less than €5 per study. Return on investment is immediate.

Professional credibility: Facing a well-informed and environmentally engaged Nantes clientele, present detailed PDF reports with comparative analyses and financial projections.

Discover PVGIS24 for professionals

Take Action in Nantes

Step 1: Evaluate Your Potential

Start with a free PVGIS simulation for your Nantes rooftop. See that the Loire Valley yield (1150-1200 kWh/kWp) is quite profitable.

Free PVGIS calculator

Step 2: Check Constraints

• Consult your municipality's local urban plan (Nantes or metropolitan area)
• Check protected areas (Bouffay, Graslin)
• For condominiums, consult the regulations

Step 3: Compare Offers

Request 3-4 quotes from Nantes RGE installers. Use PVGIS to validate their production estimates. A difference >10% should alert you.

Step 4: Enjoy Loire Valley Sun

Quick installation (1-2 days), simplified procedures, production from Enedis connection (2-3 months). Each sunny day becomes a source of savings.

Conclusion: Nantes, Western Solar Metropolitan Area

With balanced sunshine (1150-1200 kWh/kWp/year), a mild climate preserving equipment, and strong local dynamics in favor of energy transition, Nantes and the Loire Valley offer excellent conditions for photovoltaics.

Returns on investment of 9-12 years are attractive, and the 25-year gain regularly exceeds €10,000-15,000 for an average residential installation. The professional sector (tertiary, agricultural) benefits from even shorter ROI (7-9 years).

PVGIS provides you with precise data to implement your project. No longer leave your roof unexploited: each year without panels represents €500-750 in lost savings depending on your installation.

The Loire Valley climate, often perceived as rainy, actually reveals ideal conditions for photovoltaics: natural panel cleaning, moderate temperatures optimizing efficiency, and regular production promoting year-round self-consumption.

Start your solar simulation in Nantes

Production data are based on PVGIS statistics for Nantes (47.22°N, -1.55°W) and the Loire Valley. Use the calculator with your exact parameters for a personalized estimate of your rooftop.