# Example of calculating the number of photovoltaic panels needed for a home in Valencia

Next we will analyze how many solar panels I need for my house. Although the choice of the necessary elements for a photovoltaic installation is the result of a multitude of calculations and estimates, we will now try to explain with an example what factors must be taken into account for the correct choice of the number of solar panels. in a photovoltaic installation .

Let us imagine that we want to carry out a photovoltaic solar installation in a weekend home in Valencia with the following consumption:

– Fridge
– TV
– Lighting

If we make the sum of the Wh/day that we are going to consume, we obtain a total of: approximately 1,500 Wh/day.

The second step is to obtain the radiation of Valencia , in this case, of the most unfavorable month (December). Through the Photovoltaic Geographical Information System (PVGIS) page , we observe that we get an HSP value of 3.65 for a panel tilt of 30º towards the south.

To calculate the number of panels, assuming that they are oriented as indicated above with an inclination of 30º and facing south, the following formula would be used, without taking into account the typical losses of a photovoltaic installation or the safety factor :

Number of panels = Daily consumption/ (Panel power x HSP)
Number of panels = 1500/ (150 x 3.65) = 2.73 panels

This value must be rounded up, obtaining an amount of 3 panels for the most unfavorable month.

As has been said before, the only thing to take into account to correctly size a photovoltaic installation is not only the number (and type) of solar panels, but also the type of batteries that are recommended according to the needs and usual consumption. , as well as the inverter and charge regulator compatible with the solar batteries and with the number and type of solar panels chosen, or even the generator set that could add autonomy to the installation, if desired.