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How many solar panels do you need to power your home?
6, 12, 20 panels? The answer is found neither on your roof nor in a catalogue: it is on your electricity bill. Here is the calculation in three steps — consumption, region, orientation — with benchmarks by household profile, and the reason why “more panels” has no longer been the right answer since 2026.
The 3-step calculation (one bill and 5 minutes)
Step 1 — Your annual consumption. It appears in kWh on your bill or in your customer account. This is the starting point for everything: a home using 4 500 kWh/year and a home using 12 000 kWh/year do not have the same usable roof area, even if they are next door and identical.
Step 2 — The regional factor. One kWp of panels (i.e. 2 panels of 500 Wp) produces each year, depending on sunlight:
| Region | Production per installed kWp |
|---|---|
| South (Mediterranean coast, South-West) | 1 300 – 1 450 kWh/year |
| Central, West, Lyon region | 1 100 – 1 300 kWh/year |
| North, East, Île-de-France | 950 – 1 100 kWh/year |
Step 3 — The division. Annual consumption ÷ regional production per kWp = the power capacity that hits the mark. Example: a household using 8 000 kWh/year near Montpellier → 8 000 ÷ 1 400 ≈ 5,7 kWp, or approximately 12 panels. The same household in Lille → 8 000 ÷ 1 000 = 8 kWp, or 16 panels.
A useful rule of thumb: 1 kWp = 2 panels ≈ 5 m² of roof area, producing between 950 and 1 450 kWh per year depending on your region.
Why targeting 100% of your consumption has been a mistake since 2026
Instinctively, we want to “cover our entire bill”. But your home does not consume electricity when the panels are producing it: some of the production always goes to the grid — and since the June 2026 reform, this surplus has been purchased at 1,1 cent per kWh, compared with €0,1940 for each kWh you avoid buying. The direct consequence: the last panels in an oversized installation produce electricity that is sold for almost nothing.
The right target is generally between 70 and 90% of your annual consumption, depending on when you are at home — and the gap between midday production and evening consumption is much better addressed with a battery than with additional panels: our guide which battery capacity should you choose explains this calculation precisely.
Benchmarks by household profile
| Your household | Typical annual consumption | Recommended power capacity | Number of panels | Roof area |
|---|---|---|---|---|
| Couple, moderate consumption | 3 000 – 5 000 kWh | 3 kWp | 6 panels | ~15 m² |
| Family, main residence | 5 000 – 9 000 kWh | 6 kWp | 12 panels | ~30 m² |
| Large home, all-electric or electric vehicle | 9 000 kWh and more | 10 kWp | 20 panels | ~50 m² |
These three tiers correspond — not by chance — to the three formats of our turnkey offer: they cover almost all French homes. Between two tiers? Start with the smaller one: a microinverter installation can easily be expanded, while removing surplus panels never happens.
What if my roof does not face due south?
This is the final adjustment, and it is less restrictive than you might think. East or west: expect 15 to 20% less production, or 1 to 2 additional panels to compensate — plus a hidden benefit: an east/west installation spreads production throughout the day, which better matches the hours when electricity is consumed. Partial shade (chimney, tree) can be managed with microinverters, where each panel operates independently. Only a due-north orientation is not recommended. The roof pitch is much more forgiving: between 20 and 45°, the difference remains marginal.
Roof area check: is your roof large enough?
Final check before confirming your figure: available space. A 500 Wp panel occupies approximately 2,5 m²; you need a clear roof slope, preferably in one continuous section. A single-storey 100 m² home typically has 50 to 60 m² of roof area per slope — more than enough for 12 panels, even while maintaining edge clearances. If your south-facing slope is small, distributing panels east/west across two slopes is a common and effective solution. The technical survey validates all this down to the millimetre — that is its job, not yours.
Your exact number, with your bill in hand, in 30 minutes
An expert applies this method to your actual figures — consumption, region, orientation, time spent at home — and tells you how many panels are right for your home. Free, with no obligation.
Choose my time slot → Or call our experts directly: 04 49 42 00 98Frequently asked questions
How many panels are needed for a 100 m² home?
The surface area of the home is a poor indicator — two 100 m² homes can consume anywhere from one to three times as much depending on heating and occupants. Start with your bill: for typical family consumption of 5 000 to 9 000 kWh/year, the answer is most often 12 panels (6 kWp).
How many panels are needed to be self-sufficient?
Complete self-sufficiency is not the relevant objective for a grid-connected home: winter nights would require a massive oversizing of panels and energy storage, making it uneconomical for a few weeks of the year. Targeting 70 to 90% of your annual consumption with a correctly sized battery outperforms complete self-sufficiency economically in every respect.
Is it better to have more panels or a battery?
Since the 2026 reform, the battery almost always wins this contest: additional panels produce surplus sold for 1 cent, while the battery increases the value of your existing production at €0,1940 per avoided kWh. Add panels when production is insufficient, and a battery when the evening is what costs you money.
Can I add panels later?
Yes, especially with a microinverter architecture where each panel is independent: modules can be added without modifying the existing installation. This is the reason to choose the lower tier when hesitating — expansion is simple, while downsizing does not exist.
A quote offers twice as many panels as your method: who should you believe?
Ask for the figures behind the proposal: what consumption, regional production and self-consumption rate is this sizing based on? Since 2026, massive oversizing only benefits the seller — our guide how to read a solar quote gives you the 7 lines to check before signing.
Production per kWp is provided as a general estimate (PVGIS basis, south-facing orientation, standard pitch); reference panels are 500 Wp, approximately 2,5 m² per panel. Savings calculated using the EDF Tarif Bleu for the first half of 2026 (€0,1940/kWh incl. VAT) and the surplus feed-in tariff (€0,011/kWh). Article updated in July 2026.
