Glare effects in a PV system occur when the sometimes extremely bright reflections lead to visual discomfort. In some cases, such impairments can even become dangerous, for example because road users are distracted by the reflected sun rays or their vision is temporarily impaired. In a shady environment, they may not be able to see properly for a short time if they are dazzled by the PV system. The glare from solar modules can also be unpleasant for neighbours.
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, which leads to a significant increase in glare problems. The following 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 neighbouring property, for example.
• On a slope, for example on a south or west-facing slope, the reflections can shine into neighbouring houses on higher ground.
• The duration and size of the glare from solar modules is reduced over 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. An installation that was glare-free in midsummer can become a problem in autumn. Depending on the latitude, there are typical ‘glare seasons’. In Germany between March and May and from August to October; in Spain, for example, winter is particularly affected.
• The presence of neighbours also plays a major role. Neighbours who work full-time are out of the house more often during the typical glare periods and tend to complain less.
• Last but not least, the neighbourly relationship is important – if there is already a conflict, a lawyer will be called in very quickly. If the relationship is friendly, 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 neighbourhood

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

Typically, today’s PV modules are 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, the child has usually already fallen into the well 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.

Forward-looking measures

To avoid this hassle, it makes sense to use glare-free modules from the outset if there is a potential risk of glare. In addition to satinised 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 orientate 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 tough, weatherproof and UV-resistant adhesive film and a special scratch-resistant 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 climate chambers.

For further information or inquiries, please contact us at: info@phytonics.tech