solar greenhouse

Photovoltaic solar: comparisons around Alma Solar's "I'm solar 400W" panel

The increase in energy bills is the unavoidable subject of the moment, especially since the increase affects many daily services. In this context, we find it interesting to recall the advantages of photovoltaic solar energy. Especially since the prices of solar panels, such as the I'm solar 400W panel, seem to remain rather stable despite the crisis! The time to consider work in this sector because the profitability of solar energy has never been as good as it is today. Beware, some installers or sellers have significantly boosted their prices since the start of the energy crisis. Be careful and compare the quotes before signing! This comparative article will help you choose the right solar panels, both in terms of technology and costs.

Let's remember the benefits of solar energy

The first, and not the least: it is a renewable energy, that is to say an energy free and inexhaustible ! What is not the case with fossil fuels, as is the case with natural gas. In effect; not to mention the prices, their availability is not always guaranteed especially when there are geopolitical tensions as currently. Eventually, all fossil fuels will be exhausted. Conversely, with global warming, the duration of sunshine should be revised upwards in many regions, particularly in Europe. This is an asset for the production of solar energy.

On the other hand, the solar energy sector is beginning to have a few years of hindsight! One comes out democratization of components. A panel allowing a completely correct energy efficiency will now be much more affordable than a few years ago. The warranties offered on the hardware are also longer as the panels often turn out to be more durable than originally hoped.

Thus, it becomes possible to make real substantial savings using photovoltaic solar energy. Be careful, however, if you want to use solar hybrid (heat and electricity in cogeneration on the same panels). Indeed, if the idea of ​​recovering the heat released by the solar panels to heat the water or the interior of the dwelling could seem tempting, in 2022, it is more interesting to make 2 installations: a photovoltaic solar and a Solar Thermal.

For more information on the realization of a solar panel installation, do not hesitate to consult our article All about photovoltaic solar panels in 2022 and their specificities.

What characteristics should be kept in mind when choosing a solar panel model?

Monocrystalline or polycrystalline panels?

For the realization of a profitable solar installation, it is important to choose the material to be set up according to the expectations during use. So, as we discussed in a previous article, these are now the monocrystalline panels which dominate the solar energy market for individuals. The other, older types of panels are destined to gradually disappear over the next few years. These panels, whose cells are each composed of a single crystal silicon, allow an interesting yield while supporting less sunshine than polycrystalline panels, better suited to very sunny regions or to high-power solar installations where the surface is available. We can therefore, with these more recent panels, hope for good performance even in regions where the sunshine is moderate, or when the sun is low or low.

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The importance of panel performance

The efficiency of a solar panel is calculated as a percentage representing the share of energy produced by the solar panel in relation to the light energy received on the panel. Indeed, the energy that can be transformed into electricity is only part of the solar energy radiated on the panel. The following calculation must then be made:

Yield = Electrical power produced / Solar power received

For the panels currently on the market, the efficiency can go up to 24% for the most efficient panels. It revolves around 18 to 21% for the majority of recent models. In the laboratory, some panels in development can exceed 30% yield. However, these panels are still in the study and research stage. Their manufacture, relatively expensive, does not yet allow their generalization for the sector of solar energy applied to individuals. However, this leaves prospects for improvement for the coming years.

Power delivered, size of panels and number of photovoltaic cells

Solar panels are generally presented by retailers according to the power they are capable of delivering. This power is expressed in Wc (for Watt peak). It is then the maximum power what can the solar panel supply when it works in following standardized conditions :

The announced power of the panel is therefore useful information, but to be related to other criteria developed below.

For example, special attention should be paid to the size and weight of the solar panel. Indeed, at constant output, the power of a solar panel depends directly on its size and therefore on the size it takes up. Thus, depending on the surface you have, it may sometimes be interesting to turn to a panel with less power but which corresponds to the available space.

Similarly for the weight, a solar installation can represent a significant total weight on the supporting structure, in particular the frames based on light trusses.

The solar installation must also meet your electricity needs. Making an installation that produces 3 times more or 3 times less compared to your consumption no longer makes sense in 2022.

Below, a comparison of power and weight of different solar panels, including the solar panel I'm solar 400W :

technical comparison solar panels

We can see that the I'm solar 400W panel is doing quite well with only 17kg announced, for a total of 108 photovoltaic cells, a sign of good solar production! In effect, the more cells there are on a solar panel, the less the shading or solar masks will reduce its production.

Detailed comparison for the I'm solar 400W panel from Alma Solar

In addition to the fairly general criteria listed above, other criteria should also be taken into account:

The duration of the guarantee

Indeed, it can be very variable from one panel to another. Especially since it often breaks down into several parts:

  • store or dealer warranty
  • manufacturer's warranty
  • any additional installer warranty: two-year or ten-year
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It is also possible that certain warranties only apply to a very specific criterion of the panel:

  • material warranty (on manufacturing defects)
  • performance guarantee after a certain number of years of use
  • warranty on wear, or rather the absence of wear of the panel over a certain number of years of use
  • ...

For all the panels in the I'm solar range, the various guarantees put in place are relatively generous!

First, there is a 30-year manufacturer's warranty covering material defects. This is one of the longest guarantees that can be found on this type of service. To this first security is added the guarantee I'm safe. This second warranty provides linear performance over at least 25 years.

solar panel warranty comparison

Treatments applied to photovoltaic solar panels

The finishing surface treatment is not highlighted enough, yet it is a essential criterion for the lifespan of your future installation !

Indeed, the solar panels, installed outdoors, will have to withstand not only the weather, but also and above all weather conditions that are not always mild. If the panel was not carefully protected when it was manufactured, it may not last as long as you might have hoped, resulting in a replacement cost sooner than you expected. To avoid this inconvenience, here are the main concerns that can affect your solar panels, as well as the solutions that can be provided.

The PID effect

PID is an English term meaning “Potential Induced Degradation”. This is a static charge that is created between the cells and the frame of the solar panel. Yield can then be drastically reduced, up to 80% less yield in the worst case. It is possible to protect the solar panels against the PID effect, a standard: IEC TS 62804, also makes it possible to ensure that this protection has been carried out.

The I'm solar 400W panel is guaranteed against PID effect during its first 25 years of use.

The hotspot phenomenon

A Hotspot is a hot spot that tends to form at the junction between cells when some of them stop working due to uneven exposure to the surface of the panel for example. Unlike some other technical problems with solar panels, hotspots are directly visible on the panel since they take the form of black or brown spots on the affected solar cells. Here again, means can be put in place by the manufacturer to delay the appearance of these hotspots as much as possible. It can for example be a question of equipping the solar panel with bypass diodes.

The I'm solar 400W panel is also guaranteed for 25 years against the Hotspot phenomenon.

LID and LeTID effects

LID is an English term which means “Light Induced Degradation”, or in French “Degradation under the effect of light”. This phenomenon, which occurs from the first hours of exposure of the panel to light, is inevitable. It tends to reduce the efficiency of the solar panel compared to its nominal efficiency. However, the different solar panels are more or less resistant to the LID effect depending on the quality of the silicon used during their manufacture. It is therefore essential to choose a resistant panel at the time of purchase to avoid yield losses.

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LeTID also comes from English “Light and elevated Temperature Induced Degradation”. This effect occurs when the solar panel is exposed to temperatures of more than 50° and would contribute to its early degradation. For the moment, the means of avoiding this effect are still poorly known, but it could prove useful to invest in panels equipped with an integrated cooling system. Indeed, in all cases, the yield of solar production is better when the solar panels remain at reduced temperatures below 25°C.

solar panel surface treatment comparison

To learn more

Above, we have listed the main characteristics inherent in the purchase of a photovoltaic system. However, other criteria may need to be taken into account in certain specific situations. Thus certain panels dedicated to agricultural use can be treated against the production of ammonia, others will be protected against oxidation to adapt to a maritime environment. The double-glass panels are designed with photovoltaic cells encapsulated between two layers of glass, they can produce on both sides. Heavier, semi-transparent and a little more expensive, its robustness can be a criterion of choice in certain complex meteorological situations or specific installations.

Double-sided glass panels are particularly interesting for capturing the reflection of the sun's rays in a snowy environment, clear surfaces or on a transparent or semi-transparent surface...such as greenhouse, veranda or pergola. The introductory photo of this article shows a small solar installation based on 5 panels I'm Solar double-sided glass mounted on a greenhouse. For this project, the supporting structure of the greenhouse had to be reinforced.

Similarly, some facilities are designed to adapt to their environment. Thus it is possible to find panels that can tilt directly according to the exposure in order to provide the best possible solar production, but solar tracking remains rare among individuals because it is a much more complex and expensive installation than a fixed installation, both for purchase and maintenance. Solar trackers are only reserved for very specific cases.

Solar tacker


The I'm solar 400W panel seems to be a good entry-level or even mid-range choice for creating a solar installation for individuals. Its purchase price is very reasonable compared to similar panels offered on the market of the same power. For the moment, it does not seem to be strongly impacted by the effects of the increase in energy prices. Lighter than most panels of the same power, its installation is easier. For sale on the site ofAlma solar, it also has the advantage of being manufactured and Europe.

To go further, you can ask any question about the forum PV

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