Choosing which photovoltaic system to install on the roof of your home is not always easy. Before making such a decision, in fact, it is good to consider some elements, such as the amount of energy that is normally consumed, one's lifestyle, the characteristics of the roof, the different procedures needed to start the installation process and, last but not least, the investment.

What is a photovoltaic system?

A photovoltaic system is an electrical system made up of several solar panels that generate energy thanks to solar energy. The production of energy is possible thanks to the photovoltaic effect that is obtained when the sun's rays hit the modules, which are made of materials sensitive to sunlight, such as, for example, silicon.

The main component of a photovoltaic system is the photovoltaic field, i.e. the set of all the solar panels that form the system; the latter is connected by law to a disconnector which allows the system to be disconnected in the event of interventions on the network or voltage peaks. Furthermore, a 12V inverter is the component of the photovoltaic system that allows the transformation of direct current into alternating current so as to make it usable inside our homes.

In addition to these fundamental components, a photovoltaic system must also have an electronic monitoring system connected to a WiFi network to make real-time intervention possible in the event of a malfunction or failure of the system. In this regard, there are two counters:

- Production meter that measures all the energy produced
- Bi-directional counter that measures the energy input and output

How does a photovoltaic system work?

The basic element of a photovoltaic system is the photovoltaic cell, a photoelectric cell whose technical characteristics vary when exposed to light. Photovoltaic panels consist of a set of photovoltaic cells that transform solar energy into electricity.

To date, there are three types of photovoltaic cells with different characteristics based on the silicon structure from which they are composed:

- Monocrystalline
- Polycrystalline
- Amorphous

Types of a photovoltaic system

Photovoltaic systems on the market are divided into two groups:

- Stand-alone photovoltaic systems, also called off-grid or stand-alone: are systems that are not connected to any distribution network. These plants exploit electricity when they produce it or accumulate it in accumulation systems;
- Photovoltaic systems connected to the grid, also called grid-connected: are systems connected to the existing electricity distribution grid.

What type of solar panels to choose?

If you are thinking of installing a photovoltaic system, it is important to know the different types of portable solar panels characterized by the different materials used in production. If in doubt, it is always a good idea to contact professionals in the sector who will be able to advise you in the best possible way.

Solar modules can be of three types:

- Monocrystalline photovoltaic panels: the cells are built using a single crystal of silicon, allowing for greater efficiency than other types;
- Polycrystalline photovoltaic panels: the cells are obtained through the fusion of small silicon crystals. This type of module consists of dozens of cells and is characterized by an iridescent colour;
- Photovoltaic panels in amorphous silicon: they are more flexible panels but with a lower yield. These photovoltaic modules allow us to obtain results even in non-optimal exposure conditions but with a lower yield.

The consumption requirements for the installation of a photovoltaic system

Before deciding whether to install a photovoltaic system on your roof or not, it is advisable to analyze your energy consumption and, based on this, evaluate whether you really should undertake this type of long-term investment. In fact, in the home, the installation of a photovoltaic system is recommended when at least 2,500 kWh are consumed per year. However, this parameter is changing, given that electricity consumption continues to increase in the face of a change in people's lifestyles which has already seen the affirmation of electric mobility and smart homes in recent years.

The lifestyle of the applicant

An assessment of your lifestyle is advisable before choosing the characteristics of the photovoltaic system you wish to install. It is good to ask yourself what times you are most at home, what hours in which most of the appliances are used and if you have energy-intensive electrical appliances that are kept on all day (e.g. air conditioner, refrigerator).

Based on the answers, it will be decided whether to install a standard photovoltaic system or a storage system. The former is recommended for people who live at home and therefore use electricity during the day. Conversely, for those who return home in the evening, photovoltaic batteries may be the best solution. This, in fact, accumulates solar energy during the day so that it can be used at night.

Furthermore, thanks to the wide range of brands of photovoltaic batteries that Otovo offers to its customers, you can choose the one that best suits your needs.

The characteristics of the roof

The installation of a photovoltaic system can be done on roofs of different materials but not on every type of roof. Indeed, a curved surface or a thatched roof would not be suitable for a photovoltaic system. The roofs on which photovoltaic systems are commonly installed are pitched or flat roofs. The first is the classic sloping roofs, where it is necessary to create a load-bearing structure to support the panels. The latter, on the other hand, need a special inclined structure that raises the solar modules, as in pitched roofs.

Orientation and dimensions of the photovoltaic modules

The choice of orientation and inclination of the photovoltaic panels is essential to obtain excellent results: the more the modules are oriented towards the sun's rays, therefore towards the south, the better the photovoltaic effect will be. Also, make sure that nearby trees or buildings do not cast their shadow on the panels, reducing their efficiency. However, if there is a fireplace or a tree that shades the panels, it is a good idea to opt for the installation of a photovoltaic optimizer.

The size of a photovoltaic system depends a lot on the number of components used, the lifestyle of the users and the installation area. In general, a domestic-sized system, with 3 kW of nominal power, needs 15 m2 to be installed on pitched roofs and about 25 m2 for flat surfaces.

The procedures for installing a photovoltaic system

The first step in the installation process of a photovoltaic system is to identify the supplier, in our case Otovo, who will check for any constraints that could compromise the assembly of the photovoltaic panels. The results of these checks, together with the details of the system, will then be included in a project that will be sent to the installers who will carry out the work.

At this point, the applicant must communicate or request authorization from the Municipality to carry out the work to connect the system to the electricity grid. If necessary, you may also need to purchase a lifepo4 battery to store the electricity generated by the solar panels for use in case of unexpected power outages.

Economic gain and payback times of the investment

One of the questions that arise before installing a photovoltaic system in your home is whether installing photovoltaic modules is convenient or not. The answer is that installing a photovoltaic system has three economic advantages:

Self-consumption is made possible by the installation of photovoltaic systems with storage and which reduces the demand for electricity from the grid.

On-the-spot metering allows the energy produced and not consumed to be fed into the grid and then withdrawn at a later time.

The liquidation of surpluses occurs when the value of the energy fed into the grid is greater than the energy withdrawn. In this case, the GSE will pay for the excess energy introduced.

Furthermore, on average, a 4.4 kWh photovoltaic system has a yield of 20-25% per year which allows a return on investment within four or five years, depending on the type of building and roof on which the system is installed.

Other advantages of photovoltaics

In addition to the four advantages listed above, a photovoltaic system allows you to:

Save on consumption bills. Thanks to the photovoltaic system, there will be less dependence on the national electricity grid operators, and it will be possible to autonomously produce the energy necessary to meet one's needs.

Increase the value of the property. Installing a photovoltaic system increases the commercial value of your home. To calculate the increase in value, it is necessary to take into account the power of the installation, its duration, the amount of energy produced and the cost of energy.

Safeguard the environment. the sun is a natural resource that allows us to produce energy without polluting the environment.

A lifetime of a photovoltaic system

On average, a photovoltaic system with high-quality components lasts about 25 years, a duration that allows the system a rapid return on investment in economic terms and a strong reduction in environmental impact (to learn more about this topic, we advise you to read our article on the environmental impact of photovoltaic panels). Periodic and accurate ordinary and extraordinary maintenance of the entire system helps to extend the life of the system itself, increase the value of the house, and at the same time, guarantee the right yield.

Disposal of photovoltaic panels

The disposal of solar panels depends a lot on their type. In fact, it is good to understand whether it is domestic WEEE, i.e. waste with a nominal power of less than 10 kW, or professional WEEE with a nominal power equal to or greater than 10 kW.

The former must be taken to the appropriate WEEE Collection Center in the Municipality of residence, and the latter must be delivered by authorized subjects to a plant on the list of the WEEE Coordination Centre. In turn, the GSE will cover the remaining costs.

Guarantees for solar panels

Finally, once you have purchased a photovoltaic system, it is good to consider three types of guarantees:

Product - which has a duration that varies between 12 and 25 years

Installation - which by law is 2 years

Production - which has a duration of 25 years

Frequent questions

Is it worth installing a photovoltaic system?

Surely! Installing a photovoltaic system allows you to save on bills and protect the environment.

How does photovoltaic work?

A photovoltaic system consists of several solar modules, which in turn are made up of smaller units: the photovoltaic cells. When particles of light, also known as photons, strike free electrons on the silicon cell, they produce energy. This current, thanks to the inverter, can be used inside our homes.