An average home in Spain needs between 4 and 6 solar panels. If you have air conditioning, a pool or an electric water heater, between 8 and 14 is normal. To charge an electric car you need to add between 3 and 5 more panels, depending on how many kilometres you drive.
The exact number depends on two things: how much electricity you use and how much sun your roof gets. We explain how to calculate it in 3 steps.
Step 1: check how much electricity you use a year
You’ll find it on your bill or on your distribution company’s website. Look for the consumption over the last 12 months in kWh.
If you don’t have it to hand, these figures will serve as a reference:
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- The average household in Spain uses about 2,570 kWh a year, according to the CNMC. That’s about 7 kWh a day.
- A family of 4 with an electric water heater can exceed 5,700 kWh a year.
- On the coast, with air conditioning and a pool, it is easy to go over 7,000 kWh.
Step 2: work out how much each panel produces
A modern panel has about 450 W. In the province of Málaga, each installed kWp produces about 1,650 kWh a year, according to PVGIS (European Commission).
This means that each 450 W panel produces about 740 kWh a year on the Costa del Sol. In Murcia production is similar.
Step 3: divide
The formula is simple:
Number of panels = annual consumption (kWh) ÷ 740
Example: a home that uses 4,500 kWh a year needs 4,500 ÷ 740 = about 6 panels.
Table: how many panels you need for your home
| Type of home | Annual consumption | Power | Panels (450 W) |
|---|---|---|---|
| Flat, 1-2 people | 2,000 kWh | 1.2 kWp | 3-4 |
| Average Spanish household | 2,570 kWh | 1.6 kWp | 4 |
| Family of 4, electric water heater | 4,500 kWh | 2.7 kWp | 6 |
| House with air conditioning and pool | 7,000 kWh | 4.2 kWp | 9-10 |
| Large house with aerothermal heat pump | 10,000 kWh | 6 kWp | 13-14 |
Approximate calculation for Málaga and Murcia, with south-facing 450 W panels.
And to charge an electric car?
An electric car uses between 13 and 18 kWh per 100 km in normal use, according to RACE. If you add the charging losses, allow about 17 kWh per 100 km.
| Kilometres a year | Energy needed | Extra panels |
|---|---|---|
| 8,000 km | 1,360 kWh | 2 |
| 12,000 km | 2,040 kWh | 3 |
| 15,000 km | 2,550 kWh | 3-4 |
| 20,000 km | 3,400 kWh | 4-5 |
Example: a family of 4 with an electric water heater (6 panels) that drives 12,000 km a year needs about 9 panels in total.
The key with the car: when you charge it
The panels produce during the day. If your car is at home at midday, you charge it directly with the sun, for free.
If you work away from home and charge at night, you have three options:
- Smart charger: it charges the car only with surplus energy. Ideal if the car is at home at weekends or you work from home.
- Virtual battery: what your panels produce during the day is deducted from what you use charging at night.
- Physical battery: it stores the day’s energy to charge the car at night. It is the most expensive option.
Remember that installing a charging point qualifies for an income tax (IRPF) deduction.
Will it all fit on my roof?
Each panel takes up about 2 m². An installation of 10 panels needs about 20 m² free of shade.
Orientation also matters:
- South: the best.
- East or west: they produce 10-20% less, but spread production between morning and afternoon.
- North: usually not worth it.
Why not install more panels, just in case?
Because the energy you don’t use is paid at a very low price. At midday, surplus compensation can drop to almost €0/kWh. It is better to size the installation to your real consumption and only leave a margin if you have specific plans: an electric car, a new air conditioner or a pool.
Frequently Asked Questions
How many panels does a 100 m² house need?
Square metres are not what matters. What counts is consumption. A 100 m² house with 3-4 people usually needs between 4 and 6 panels.
How many solar panels do you need to charge an electric car?
Between 3 and 5 more panels, for 12,000-20,000 km a year.
Can I start with a few panels and expand later?
Yes, but it is worth planning the inverter from the start. If you are thinking of buying an electric car in the next few years, tell your installer.
How much roof space do I need?
About 2 m² per panel. For 8 panels, about 16 m² free of shade.
How many panels do I need to be 100% self-sufficient?
With panels alone, it is not possible: they don’t produce at night. To get close to 100% you need batteries, and the installation costs considerably more.
Want to know exactly how many panels your home needs? Request your free study. We install in Málaga, Marbella, Murcia and the rest of Spain.
