Glare effects in a PV system occur when reflections, some of which are extremely bright, cause visual discomfort. In some cases, such impairments can even become dangerous, for example because traffic participants are distracted by the reflected sun rays or their vision is temporarily impaired. In a shade environment, they are temporarily blinded by the glare from the PV system and therefore unable to see properly. This glare from solar modules can become irritating for neighbors as well.
In the past, solar modules generally faced south in order to convert as much sunlight as possible into electricity. In these cases, the light is usually reflected upwards so that glare rarely occurs. Nowadays, however, more and more solar systems are being installed with other orientations, leading to a significant increase in glare problems. Below is a brief list of the most important risk factors for glare from solar modules:

• Photovoltaic systems facing east, west or north tend to reflect the light downwards, causing glare on the terrace of the neighboring property, for example.

• On a hillside, for example on a southern or western slope, the reflections can shine into neighboring houses on higher ground.

• The duration and size of the glare from solar modules is reduced at a greater distance. If, on the other hand, the houses are close together, the glare problem increases both temporally and spatially. The viewing angle also plays a role.

• There are major seasonal effects due to the changing position of the sun. A system that was glare-free at the height of summer can become a problem in the fall. Depending on the latitude, there are typical “glare seasons”. These are between March and May and from August to October in Germany, while in Spain, for example, winter is particularly affected.

• The amount of time neighbors are present also plays a major role. Neighbors who work full-time are out of the house more often during the typical glare seasons and tend to have less tendency to complain.

• Finally, the relationship between neighbors is important – if a conflict already exists, a lawyer will be called in very quickly. If the relationship is based on friendship, on the other hand, there is often a willingness to find a solution together and possibly even share the costs.

High quality of living in a good neighborhood

In many residential areas, interest in PV systems is increasing, making glare from solar modules an increasingly relevant issue. In the interests of good neighborly relations, it is therefore important to consider the above-mentioned risk factors before installing a PV system.

If neighborly relations are already somewhat difficult, you should place particular emphasis on avoiding glare from photovoltaics and, if in doubt, obtain a glare assessment. This is not only about the optimum installation location and angle, but also about the nature of the modules.

Misunderstanding “anti-reflective coating”

Today’s PV modules are typically provided with an “anti-reflective coating” (ARC). Unfortunately, this coating only serves to increase yield and offers no protection against glare. Many solar installers are unaware of this fact, or fail to mention it due to a lack of alternatives. Once the modules are on the roof, trouble has usually already started and the solutions then suggested, such as planting a hedge or using blinds, are of little help. Dismantling the PV system following an expensive and nerve-wracking legal dispute is the typical outcome.

Future-oriented measures

To avoid this trouble, using glare-free modules from the outset makes sense if there is a potential risk of glare. In addition to satinized modules, such as those sold by 3S or Megasol, Phytonics offers an innovative product that can be used to “de-glare” any solar module: With its special, micro-structured surface, the XRF anti-glare film ensures that flat incident light in particular is better coupled and the reflected rays are completely diffused. As a result, there are no more direct reflections of the sun, which could cause glare. Even with a very flat incidence of light of 70° to the surface normal, the reflected brightness of 75,000 cd / m² remains well below the value of 100,000 cd / m² often quoted for glare. However, caution is advised with so-called “anti-glare” modules, which are based on deeply textured glass. These cannot adequately suppress the reflections of flat incident light, but sometimes distribute them in such a way that the glare problem is exacerbated.

The anti-glare film from Phytonics allows you to align the solar modules as you wish without the risk of glare. Measurements show that the film clearly outperforms other glare-reducing surfaces. At the same time, the high performance values are maintained so that the annual energy yield remains virtually unchanged.

The XRF anti-glare film consists of a durable, weatherproof and UV-resistant adhesive film and a scratch-resistant special layer with a textured surface. These two components have already been in outdoor use worldwide for many years, and the film’s outstanding durability has also been proven in accelerated ageing tests in climatic chambers.

Please contact us for further information or questions: info@phytonics.tech