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With or without a battery: the 5-question test
This is the number one question at all our consultations: “is a battery worth it for me?” The good news is that your situation already contains the answer. Take 3 minutes and answer the 5 questions below, counting your A and B answers — the verdict is at the bottom, with the figures to support it.
The test
Question 1 — During the week, between 10 a.m. and 5 p.m., your home is…
A. Occupied: working from home, retired residents, young children — life is happening, and electricity is being used during the day. B. Empty: everyone leaves in the morning and comes home in the evening.This is the question that carries the most weight. If you are at home during the day, you use solar power when it is being produced — the battery has less work to do. If you are away, your midday production has no one to serve: without energy storage, it is sent to the grid for 1 cent.
Question 2 — Your typical evening (5 p.m. – midnight) is more…
A. Light: a simple meal, one screen, and few appliances running in the evening. B. Busy: full cooking, washing machine or dishwasher, hot-water tank, and supplementary heating.The battery discharges during your evening. The more electricity you use, the more each stored kWh finds a use — and the more profitable energy storage becomes. A light evening, on the other hand, leaves a large battery half unused.
Question 3 — Your annual consumption is…
A. Below 5 000 kWh/year: a moderate household. B. Above 5 000 kWh/year: a family, an all-electric home, or an electric vehicle.The figure is on your bill. The larger the volume, the more the difference between “45% self-consumed” and “75% self-consumed” amounts to hundreds of euros — it is simply mathematical.
Question 4 — In terms of budget, you can finance…
A. The panels, and that is already a good start: adding a battery would mean reducing the system's power. B. The complete project, panels and energy storage, without compromising on system sizing.Absolute rule: never sacrifice panels for a battery. Panels create the value; the battery shifts it. If your budget forces you to choose, choose panels first — energy storage can be added very easily in two years, especially with a modular system.
Question 5 — Power cuts at your home are…
A. Extremely rare and have no consequences. B. Regular, or critical (a full freezer, medical equipment, intensive remote working).Some battery configurations keep your essential circuits running during a power cut. This is not the primary economic argument, but if a power cut costs you a lot or causes you anxiety, it is a real point in favour of a battery — to be specified during the assessment, because not every configuration provides this function.
The verdict
| Your score | Verdict | Why |
|---|---|---|
| 4 to 5 A | Without a battery, for now | Your presence and your usage profile already do the work of energy storage. Invest everything in properly sized panels — and keep an upgradeable system architecture for later. |
| A/B mix | A modest battery (5 kWh) or add one later | Energy storage will benefit you, but not at the maximum rate. A small modular capacity captures most of the benefit without overinvesting — and can be expanded when your usage profile changes. |
| 4 to 5 B | Clearly, with a battery | Away during the day, busy evenings, high consumption: you are exactly the profile batteries were invented for. It is the first euro to invest after the panels. |
The approximate figures behind the verdict: on a 6 kWp residential installation in southern France, the battery increases the annual savings from approximately €784 to €1,245 — but only if your profile (questions 1 to 3) gives it enough work to do. The detailed figures are in our guide what are the real savings by profile?.
Did you answer “with a battery”? The next question is the size
A positive verdict immediately raises the question of sizing — and this is where actual profitability is determined: a battery that is too large dilutes the savings, while one that is too small leaves money on the table. Our guide which battery capacity should you choose? gives you the method in 5 minutes, with your bill at hand. And to understand the different formats (coupled, all-in-one, plug & play), the complete battery guide covers everything.
Did you answer “without a battery”? Two ways to keep the door open: choose an architecture that can accommodate energy storage later (this is the case with our installations), and review your figures a year from now — your monitoring app will show you exactly what you inject into the grid. If this figure increases, the battery will justify itself, with the data to prove it.
The test gave you a direction. The assessment gives you the figure.
Choose my time slot (30 min, free) 04 49 42 00 98Frequently asked questions
Can a battery be added later without any penalty?
Yes, if the installation was designed for it: a hybrid inverter or an energy storage-compatible architecture. This is something to require from the initial quote, even if you start without a battery — it can then be added without replacing anything. Our configurations include this as standard.
Does working from home really make a difference?
A huge one: being at home during the day increases natural self-consumption from 40% to 55–65% without any equipment. This is why two identical homes can have two opposite verdicts — the test is based on your habits, not your roof.
Is a battery without solar panels worthwhile?
Only marginally in France for a private individual: charging the battery from the grid at night to use the energy during the day only captures the difference between off-peak and peak hours, which is far smaller than the difference between production and the Tarif Bleu rate. A battery makes full sense when coupled with solar production.
What about a virtual battery in this test?
A virtual battery is a subscription that “credits” your surplus instead of storing it physically. Since the 2026 reform, its financial equation has deteriorated compared with physical energy storage for most profiles — we will be dedicating a detailed comparison to it shortly.
My score is 3 A / 2 B. What should I do?
You are in the “modest or deferred battery” category: request an assessment with both scenarios shown side by side. The difference in annual savings between the two will tell you, in euros, whether the battery's €3,000 cost will work hard enough — that is exactly what the free assessment does.
Savings calculated using the EDF Tarif Bleu rate for the first half of 2026 (0.1940 €/kWh incl. VAT) and the surplus buy-back rate (0.011 €/kWh), based on a typical 6 kWp installation in southern France. Self-consumption rates are given as observed ranges. Article updated in July 2026.
