In an apartment, you are limited by available space, legal constraints, and the power authorized in plug and play (800W maximum without an electrician). The question is not "how many do you want to install" but "how many can you install according to your configuration".

Quick Answer: Number of Panels According to Your Situation

Balcony 3-4 m²: 1 panel 400W → 360-560 kWh/year → Savings 60-95€/year

Terrace 6-8 m²: 2 panels 800W → 720-1120 kWh/year → Savings 120-190€/year

Railing only: 1-2 vertical panels depending on length (1 panel/2 meters)

Without outdoor space: Collective rooftop condominium project (8-20 panels depending on surface)

Maximum authorized without complex declaration: 800W = 2 panels of 400W. Beyond that, obligation to call an RGE electrician.

Calculation According to Your Electricity Consumption

Sizing by Annual Consumption

Annual consumption	Recommended panels	Production covered	Annual savings
2000-3000 kWh/year (studio)	1×400W	15-25%	60-95€
3000-5000 kWh/year (T2/T3)	2×400W	20-30%	120-190€
5000-8000 kWh/year (T4+)	2×400W + 1.5 kWh battery	15-25% optimized	150-250€

How to Identify Your Consumption

Via Linky meter:

• Enedis application (free): consumption history month by month
• Supplier application (EDF, Engie, etc.): real-time monitoring
• Last electricity bill: total kWh consumed over 12 months

Averages by type of housing:

• Studio/T1 (25-35m²): 2500 kWh/year
• T2 (45-60m²): 3500 kWh/year
• T3 (65-80m²): 5000 kWh/year
• T4+ (80-100m²): 6500-8000 kWh/year

Important: These panels only cover part of your needs. The objective in an apartment is to reduce the bill, not to achieve total autonomy (impossible with the available surfaces).

To choose the right kit adapted to your consumption, analyze your daily consumption peaks.

Calculation According to Available Space

Surface Required per Panel

Standard 400W panel dimensions:

• Width: 100-110 cm
• Height: 170-180 cm
• Panel surface: 1.7-2 m²
• Total surface required on ground with 30° inclination: 2.2-2.6 m²

Mandatory spacing:

• Between 2 panels: minimum 15 cm
• Around the panel (maintenance): 20 cm
• For optimal inclination: +30% ground surface

Consult exact dimensions according to models before purchase.

Configuration According to Type of Space

Type of space	Available surface	Optimal configuration	Annual production
Continuous balcony	3-4 m²	1 panel inclined 30°	360-560 kWh
Large terrace	6-10 m²	2 panels inclined 30°	720-1120 kWh
Railing only	2-4m linear	1-2 vertical panels	250-500 kWh
Window sill	1-2 m²	1 mini-panel 200W	180-280 kWh

Practical rule:

• 1 standard panel = 2 m² minimum on ground (with inclination)
• Railing = 1 panel every 2 linear meters
• 800W limit in plug and play = maximum 2 panels of 400W

Orientation and Yield Loss

Your balcony is not facing due south? Here are the real losses:

• South: 100% yield (reference)
• South-East or South-West: -5% to -10%
• East or West: -20% to -25%
• North-East or North-West: -40% to -50%
• North: -60% to -70% (unprofitable installation)

A panel oriented East or West remains profitable if your consumption is concentrated morning or evening. Analyze the advantages and disadvantages according to your orientation.

Legal and Technical Constraints

Installation Rules by Status

Condominium owner:

• Check condominium regulations (some prohibit facade modifications)
• Balcony installation <1.80m from ground: no authorization
• Balcony installation >1.80m: prior declaration to town hall (response within 1 month)
• 800W micro-inverter limit without Enedis declaration

Tenant:

• Written owner agreement mandatory
• Favor removable panels (portable when moving)
• Temporary attachment without drilling condominium wall
• Same 800W limit

Condominium roof (collective project):

• General assembly vote absolute majority
• Work declaration to town hall
• Grid connection: collective contract
• Production distribution among co-owners

Maximum 800W: Why This Limit

French regulations authorize up to 800W in plug and play without an electrician or heavy procedures:

• Simple connection to domestic outlet
• No modification to electrical installation
• Simplified Enedis declaration (online form)
• Compatible with existing meter

Beyond 800W, you switch to a conventional installation:

• RGE electrician mandatory
• Electrical panel modification
• Specific connection
• Installation cost multiplied by 3-4

For an apartment, 2 panels of 400W = optimal maximum configuration.

Real Production by Configuration

1 Panel 400W

Annual production: 360-560 kWh depending on region

• Northern France: 360-420 kWh/year
• Central France: 420-500 kWh/year
• Southern France: 500-560 kWh/year

What it covers continuously (based on 400 kWh/year):

• Internet box (150 kWh/year) ✓
• Class A refrigerator (130 kWh/year) ✓
• LED house lighting (100 kWh/year) ✓
• Total: 380 kWh/year perfectly covered

Annual savings: 60-95€ (rate 0.17€/kWh)

2 Panels 800W

Annual production: 720-1120 kWh depending on region

What it covers in addition to the base (800 kWh/year):

• Base above (380 kWh)
• Washing machine 10 cycles/month (150 kWh/year)
• Dishwasher 15 cycles/month (200 kWh/year)
• Laptop 6h/day (50 kWh/year)
• Total: 780 kWh/year covered

Annual savings: 120-190€

Discover the best 800W kits for this configuration.

With Storage Battery

Without battery, you only consume 40% of your production (the rest injected free on grid during daytime).

With battery:

• Self-consumption rate: 40% → 85%
• Production 800 kWh/year
• Real self-consumption: 680 kWh instead of 320 kWh
• Additional gain: 360 kWh = 60€/year
• Battery investment: 900-1500€ for 1.5-2 kWh
• Profitability: 15-25 years (with annual battery price decrease 15%)

Complete guide: which battery for plug and play solar panel

Solutions by Type of Apartment

Studio/T1 (25-35m²)

• Consumption: 2000-3000 kWh/year
• Solution: 1 panel 400W
• Production covered: 15-25%
• Investment: 400-600€
• Profitability: 6-8 years

Typical configuration:

• 1 panel 400W on balcony or railing
• Integrated micro-inverter
• Standard outlet connection
• Without battery (not profitable)

T2/T3 (50-70m²)

• Consumption: 3500-5000 kWh/year
• Solution: 2 panels 800W
• Production covered: 20-30%
• Investment: 800-1200€
• Profitability: 5-7 years

Typical configuration:

• 2 panels 400W on terrace or continuous balcony
• 800W micro-inverter
• Series wiring between panels
• Optional 1.5 kWh battery (+900€)

T4/T5 (80-100m²)

• Consumption: 6000-8000 kWh/year
• Solution: 2 panels 800W + 2 kWh battery
• Production covered: 15-20% (but optimized)
• Investment: 1800-2500€
• Profitability: 8-10 years

Typical configuration:

• 2 panels 400W optimal inclination
• 2 kWh storage battery
• Intelligent charge/discharge management
• Consumption monitoring application

Without Balcony/Terrace

Solution: Collective condominium rooftop project

• 8-20 panels depending on roof surface
• Production 6000-15000 kWh/year
• Distribution among co-owners (distribution key)
• Common charges reduction (lighting, elevator)

Procedures:

• Form group of interested co-owners (minimum 3-5)
• Feasibility study by RGE installer
• GA vote absolute majority
• Possible subsidies (local authorities)

Special Cases and Optimizations

Partially Shaded Balcony

If shadow cast 3-4h/day on panel:

• Production loss: 30-50%
• Solution: power optimizers (1 per panel)
• Cost: +100-150€ per panel
• Extended profitability: +2-3 years

Temporary Installation (Tenant)

Favor:

• Strap/tensioner attachments (without drilling)
• Portable dismountable panels
• Weighted supports (20-30 kg)
• Micro-inverter with removable plug

Maximize Production Limited Space

Bifacial panels: capture light from 2 sides

• Production: +10-20% vs standard
• Price: +15-20%
• ROI: identical but superior production

Solar trackers (follow sun's path):

• Not suitable for balcony (bulk)
• Alternative: manual adjustment of summer/winter inclination

Conclusion

Number of panels according to your apartment:

• Studio: 1 panel (400W)
• T2/T3: 2 panels (800W)
• T4+: 2 panels + battery
• Without balcony: Collective rooftop project

Regulatory limit: 800W maximum in plug and play without electrician

Profitability: 5-8 years depending on configuration, then 15-20 years free production

Minimum space: 2 m² per panel (4 m² for 2 panels)

Most apartments can install 1-2 panels. Beyond that, space and regulatory constraints make the project complex and not very profitable.