Energy autonomy through solar power is attracting a growing number of households in the Var and the Alpes-Maritimes. Yet determining how many solar panels you need, how to size your photovoltaic system or how much installation will cost often raises questions.
Because every home is unique, it’s essential to rely on concrete indicators: home size, annual electricity consumption and the right production capacity.
Here’s how to accurately assess your needs based on your home’s surface area.
How Do You Calculate the Right Number of Solar Panels?
The first step is to understand your annual electricity consumption, usually listed in kilowatt-hours (kWh) on your energy bills.
The higher your consumption, the greater the production capacity required — and therefore the number of solar panels needed to reach an optimal level of energy autonomy.
If you want to understand the technical basics before starting your project, feel free to read our article on how a photovoltaic system works.
The size of your home also directly influences the size of your solar array. It provides an estimate of your consumption but also determines how much available surface area you have to install photovoltaic modules.
This means checking how many panels can fit on your roof or solar carport while considering usable space.
Estimates Based on Home Size
For a standard 100 m² home (4 occupants), average electricity use is generally 3,000 to 4,500 kWh/year (without electric heating).
If the household is fully electric (heating + hot water), consumption rises to 8,000–10,000 kWh/year.
A 150 m² home with a pool and air conditioning can reach approximately 12,000 kWh/year.
Panel output varies depending on model (typically around 425 Wc today), and also depends on roof orientation, tilt and regional sunlight levels.
As a reference, a modern solar panel generates 550 to 600 kWh/year under Mediterranean sunlight (vs. ~400 kWh in northern regions).
To significantly offset the electricity bill for a 100 m² home, households typically install:
- 3 kWc → 6 to 8 panels
- 6 kWc → 14 to 16 panels for high-consumption households
A qualified professional will refine these figures by analysing all site-specific parameters.
Key Factors That Influence System Sizing
The correct size of your photovoltaic system depends on many criteria:
- Annual household electricity consumption
- Available roof surface and orientation
- Type and efficiency of solar panels
- Desired self-consumption level or sale of surplus electricity
- Local climate (sunlight, temperature)
- Additional needs (heating, EV charging, electric mobility)
Orientation (ideally south, but east–west also works very well for self-consumption), optimal roof tilt (25° to 35°), lack of shading, and the potential addition of battery storage all influence sizing accuracy.
Other elements include inverter choice (string or microinverters), equipment quality and compliance with electrical safety standards (validated by the Consuel certificate).
Together, these factors ensure optimal solar production and long-term reliability.
What Budget Should You Expect for a Solar Installation?
Installation costs vary depending on home size, number of solar panels required and the level of autonomy targeted (self-consumption, battery storage, or selling excess electricity).
In Provence–Côte d’Azur:
- A small 3 kWc system starts around €7,500
- A complete 9 kWc system for high autonomy can exceed €18,000
The cost per watt-peak (Wc) usually decreases as system size increases, making larger installations more cost-effective.
Pricing includes equipment, professional installation, grid connection, administrative handling and sometimes connected monitoring tools.
Installation Costs for 100 m², 150 m² and 200 m² Homes
Here are updated benchmarks for common configurations:
Home size (typical profile) | Recommended power | Approx. number of panels | Estimated cost (before incentives) |
|---|---|---|---|
100 m² (Standard) | 3 kWc | 6-8 | €7,500 to €9,000 |
150 m² (Full electric + pool) | 6 kWc | 14-16 | €12,000 to €15,000 |
200 m² (High consumption) | 9 kWc | 20-24 | €17,000 to €21,000 |
These ranges account for differences in equipment, configuration and available options.
Incentives for 2025, such as the self-consumption premium and reduced VAT, help reduce the net investment.
A personalised assessment is always recommended to size your system accurately and benefit from available financial support.
What Savings Can You Expect? Energy Reduction and ROI
A well-designed solar installation generates tangible savings on electricity bills.
Self-consumption often covers 30–60% of needs, especially when usage habits are aligned with production hours.
Excess electricity injected into the grid can also generate income through surplus sales.
In the Var and the Alpes-Maritimes, the typical return on investment ranges from 6 to 10 years, depending on system size, production capacity and the evolution of electricity prices.
Benefits include:
- Immediate reduction of energy expenses
- Increased property value thanks to energy autonomy
- Protection against future electricity price hikes
- Active contribution to the region’s environmental transition
Frequently Asked Questions About Choosing and Pricing Solar Panels for Your Home
What are the essential criteria for choosing the right number of solar panels for a 100 m² home?
To determine the correct number of panels, start by analysing your annual electricity consumption, then assess the available roof surface.
For standard consumption, households typically install 6 to 10 panels (3 to 4 kWc).
Key criteria:
- Annual consumption in kWh
- Available roof space
- Desired level of energy autonomy
What are the main steps to correctly size a residential solar installation?
For optimal system sizing, you should:
- Review your energy bills in detail
- Conduct a technical on-site assessment
- Evaluate potential yield (orientation, tilt, shading)
- Define your objectives (self-consumption with or without surplus sale)
- Determine installation cost and expected ROI
A personalised study remains the best guarantee of a profitable, long-lasting project.
What is the average installation cost for a 150 m² or 200 m² home?
For a 150 m² home requiring a 6 kWc system, installation costs range from €12,000 to €15,000, using around 14 to 16 panels.
A 200 m² home typically requires 9 kWc, costing €17,000 to €21,000, with about 20 to 24 panels.
You can check our detailed pricing and incentives page for more information.
| Home size | Total power | Estimated price range |
| 150 m² | 6 kWc | €12 000 to 15 000 |
| 200 m² | 9 kWc | €17 000 to 21 000 |
How can you optimise the performance of your solar panels at home?
To improve solar performance:
- Choose high-efficiency modules
- Ensure proper orientation (South, East or West)
- Avoid shaded areas
- Use microinverters if partial shading is unavoidable
- Adjust daily habits to consume electricity during daylight hours
Good practices:
- Monitor solar production regularly
- Clean your panels and maintain the system
- Program household appliances intelligently
