How many solar panels do I need?

If you are thinking of installing solar panels in your home, you should know that you will save up to 75% on your electricity bill. Additionally, photovoltaic installations can be set up quickly and easily.

It is however natural for you to be unsure of the number of panels required to enjoy clean and sustainable energy.

Depending on the features of your home, Energy Nordic can assist you in determining how many solar panels you require.

How to determine how many solar panels I need for a house?

To find out how many panels your home needs, we must take into account various factors that will determine the amount of sunlight that can reach your location.

Below is a list of each of these factors:

How large is your roof?

First of all, you need to know how many solar panels you can place on your roof.

If we assume it is an ordinary country house roof, it will be between 40 and 60 m2.

Example: Let’s say your roof has an area of 60 m2 and one plate of solar cells has an area of 1.65 m2. Then your roof can accommodate about 36 solar panels.

Calculations: 60 m2 / 1.65 m2 = 36 solar panels.

How much electricity do you consume per year?

Next, calculate how much electricity is consumed in your household each year. This will give you an idea of how much energy your solar panels need to produce to satisfy your current energy consumption.

Calculations: 36 solar panels 270 watts 1000 = 9720 kWh

In other words, solar panels would produce almost half of all the electricity consumed in your home each year.

Calculations: 9720 kWh / 20000 kWh = 0.486 = approx. 49%.

Quality and performance of photovoltaic panels

The quality of the panels is critical to their performance in producing energy. Higher quality systems cost a little more. However, they make better use of sunlight and are able to produce more electricity.

The higher the quality of the solar panels, the less you need to install on your roof. As it is an investment, the good performance of the solar panels will pay for the installation more quickly.

Type of solar panel according to cell type

The technology used to manufacture the cells of a photovoltaic panel will have a direct influence on its performance. Depending on the technology used, three types of solar panels can be distinguished:

  • Monocrystalline: black in colour and with rounded corners. They are mainly used to produce solar energy in homes and are perfectly adapted to the Spanish climate, as they are capable of generating energy with minimal amounts of sunlight. Their cost is high due to their complex manufacturing process, but they retain 80% of their efficiency 25 years after installation.
  • Polycrystalline: they have a lower efficiency than the previous ones, which implies a lower production cost and a cheaper price. They also retain 80% of their efficiency 25 years after installation.
  • Amorphous: they are the cheapest but the useful life of this type of solar panel is shorter than that of crystalline panels.

Power of the installation

The power of the solar panels will indicate the amount of electrical energy they are capable of producing. The total power of the installation is the sum of the power of all the panels that make it up.

Calculation: Number of panels * power of each panel (Wp) = Power of the installation (Wp)

Orientation and inclination of the roof

Specifically in Spain, the optimal orientation of the solar panels is south-facing. This is the best position for the solar panels to capture the light and produce electricity in your home.

In the case of south-east or south-west orientations, the efficiency loss is only between 1% and 4%; whereas, for east and west orientations, the efficiency can decrease by as much as 20 to 30%, so it may be necessary to install a larger number of solar panels in order to achieve the required power output. However, when the orientation of the roof is north, a prior study should be made to evaluate the effectiveness of the installation.

What is your budget?

Solar panels are a profitable investment in the long term. The number of solar panels you need also depends on your budget and how much you are willing to buy.

What is the size of the main fuse of the property?

When we are talking about larger properties, such as a block of flats or businesses, it is important to consider the size of the property’s central fuse, i.e. how much your grid can produce.

If you would like more solar panels than the main fuse allows, you will need to replace the fuse with a larger one.

The geographical location of the house

Not all provinces in Spain receive the same amount of solar radiation, so taking geography into account when installing solar panels is also important.

In these cases, we recommend asking for advice and a personalised study of the situation: roof, budget and geography. This way you will achieve optimal results once you switch to solar energy.

Let’s calculate the number of solar panels you need…

Contact our solar team to estimate the number of solar panels you need. Tell us your address and calculate monthly electricity consumption – we’ll take care of the rest.

Unlike other companies, if you have your energy supply with us we compensate you with the market rate of the price given by your distributor per kWh to ensure you get the very best rate for the energy you produce!

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