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How to calculate how many solar panels you need for your house

En este post te explicare How to calculate how many solar panels you need for your house. Carrying out an electrical installation at home is simple if you know how. To do this, you must take into account some essential aspects such as the type of installation you are going to carry out —if it is isolated or connected to the network—, the materials that will be needed in each case and, of course, the number of photovoltaic solar panels that you are going to use —for make the most of sunlight, but without wasting energy—. Next, we explain everything you need to know to be able to calculate solar panels for your home so that you can save a significant sum of money each month on your electricity bill. Continue reading for more information.

Calculate the necessary solar panels: previous aspects to take into account

To calculate the solar panels needed in a home, it is essential to take into account three essential aspects, first of all. These are the energy consumption of the house, knowing what is the available surface with which we have to carry out the installation and knowing what the orientation of the roof is. We explain them in more detail in this section.

Calculate the energy consumption of the house

Perhaps this is the most important aspect to be able to calculate the necessary solar panels. This is so because, by knowing the energy consumption of our home, we can make a very rough estimate of how many solar panels we need to meet our energy needs. To calculate the energy consumption of the house we must consult the number of kWh that we consume. However, it is essential to learn to discriminate the energy consumption of the house during the hours of the sun. The reason for this is because the solar panels will only work with solar radiation, so we must calculate the exact amount we need for those moments of light and for them to produce the right and necessary energy, making the most of it —and without there is waste.

Analyze the available surface

The next thing you should do, before buying anything, is to analyze the total area you have on your roof or terrace in order to carry out the photovoltaic solar installation. The calculation of solar panels largely depends on it. Sometimes the problem is not only in the space, but in the shadows that are produced. You must take into account, also this last detail.

Know the orientation of the roof

The orientation of the roof is also essential, since this will limit the use of solar radiation to a greater or lesser extent and, therefore, the amount of energy that can be produced. In other words, it will serve as a reference to know if we need more or fewer solar panels. As a general rule, you should bear in mind that if the orientation is South-East, the use will be greater; while if the orientation is South-West, the use will be lower. On the other hand, it is important to take into account the orientation of the solar panels when installing them. These must always be facing South and with an inclination of approximately 35º.

How to size and calculate the necessary photovoltaic solar panels

Now that we have analyzed the most relevant aspects before carrying out the calculation of solar panels, it is important that we take into account -also- two specific aspects about solar panels. These are:

  • Solar panel power: The power of the solar panel is nothing more than the amount of energy that it can produce. Therefore, based on this and from the energy that we consume during the hours of sun, we will carry out the calculation of solar panels. Of course, the higher the power of the solar panel, the fewer devices we will need.
  • Solar panel materials: The solar panel material also influences the use of energy. To carry out the calculation of solar panels for the home, it is essential to know what material the solar panel is made of —specifically, the material of its cells—. This can be monocrystalline silicon, polycrystalline silicon or amorphous silicon.

Calculation of solar panels How to do it?

The first thing we must do is calculate the consumption in hours of light that we have per year. To do this, we must use a consumption meter. This device allows us know in real time the electricity that is being consumed. It can be individual, for certain appliances, or global, to know the data in the entire home. The consumption meter is placed in the electrical panel and connected to the installation to monitor all the expenditure in kWh.

Once you have made an approximate calculation of how much energy you can consume per year, you must take into account the total power of the plates that you will need. For this you have to Divide the consumption of the house by the Peak Solar Hour (HSP). The HSP is a unit of measurement used to express the solar irradiation per surface. That is, it serves to know the amount of solar energy received by a square meter of surface. There are different tables that can be found on the internet with which you can do the calculation easily. Once you have the two measurements you will be able to obtain the total power of the necessary solar panels. Finally, to conclude with the calculation of solar panels for the house that you need, you will have to divide the result of both measurements (expressed annually) between the power of one of the solar panels. This will give you the total number of devices you will need.

How much can I save on my electricity bill with a photovoltaic solar installation?

In general, you should know that carrying out a photovoltaic solar installation in a home it can represent an approximate saving of 50 to 70% in the price of the invoice of light —as long as it has been done correctly—. Now, you must bear in mind that the region of the country in which you are located and the number of hours of light per day also have a great influence. Thus, the north of Spain (less solar radiation) is not the same as the center or south (greater solar radiation).