A typical case – glare from PV system

We receive daily inquiries from PV system owners, neighbors, and installers who have been caught off guard by a glare problem. Each case has its peculiarities, but there are many commonalities and recurring stories, misunderstandings, and disputes that we want to illustrate for you here using the fictional case of a Mr. Müller as an example: 

The Müllers live in a single-family house in a quiet residential area. To contribute to combating climate change, but also because of the recently high energy costs, the Müllers want to carry out their very own energy transition: They are purchasing an electric car, replacing the gas heating with a heat pump, and of course, the electricity should come as much as possible from their own roof. Therefore, the Müllers try to install as many solar modules as reasonably possible. In addition to the southeast roof, the northwest roof is also to be fully equipped with modules. After all, solar modules have become very affordable, and excess electricity can be stored in the 30 kWh home battery. 

It is May, the solar technician has finally come and installed the modules – from now on, the Müllers are happy – they have cheap, climate-friendly electricity in abundance and are proud to set a good example in the neighborhood. 

The scaffolding has been taken down again, and already the first real sunny day in a long time arrives – the PV system on the roof produces a fantastic amount of electricity, the electric car and battery storage are fully charged by evening, which Mr. Müller follows on his smartphone thanks to the smart integration of all components. 

The next morning, there is a knock at the door; it is the neighbor, Mr. Schumann. Mr. Müller opens the door beaming with joy, as Mr. Schumann surely wants to congratulate him on the PV system and is interested in the details. 

Instead, Mr. Schumann gets straight to the point without a greeting: "The solar panels on your roof – they have to come down immediately! Yesterday we were permanently blinded for over two hours, staying on the terrace is no longer possible for us!" 

Mr. Müller is perplexed and lets his neighbor show him the problem – indeed, the glare effects are immense, there is no arguing about that. The solar installer is also (or at least pretends to be) surprised. He insists that this has never happened to him before, moreover, he installed specially anti-reflective modules and refers to the module datasheet, which states that the front glass is anti-reflective coated. 

After the initial shock has been digested, all three affected parties begin to think about a solution. They consider whether the neighbor could simply use an awning, or whether planting a hedge could block the view of the roof and thus the dazzling reflections. Or whether by mounting the modules on a frame, the emission angles could be changed so that the light no longer reaches the neighbor. A seasonal covering of the modules with a tarp is also discussed. 

Upon closer examination, however, all solution approaches prove to be impractical. But since Mr. Müller is also unwilling to dismantle his modules, the fronts harden and the neighbor issues an ultimatum: a solution must be found by the next glare season in spring, otherwise he will involve his lawyer. 

The next spring arrives, and the glare returns. Subsequently, Mr. Müller receives a letter from the neighbor's lawyer stating that legal action will now be taken. A first court hearing follows, an expert is commissioned who confirms that there is an unreasonable glare. The court then orders the dismantling of the system. 

The seriousness of the situation prompts Mr. Müller to intensively research further solutions again, and he finally comes across the possibility of reducing glare from the modules by applying a special film. He receives a sample from the film supplier, which he then shows to his neighbor. They agree to give it a try and initially apply the film to a single module. Since Mr. Müller's solar installer is also glad to get off lightly in this matter, he agrees to carry out the film application work. For this, the module must be dismantled, then thoroughly cleaned, and put back on the roof.  

On the next sunny day, the result can be evaluated: while the surrounding modules glare enormously, the foiled module is absolutely glare-free and is not perceived as disturbing.  

At the next appointment with the judge, the parties agree that all modules will be foiled and the neighbor will drop his lawsuit in return. The costs for the foiling will be shared by the solar installer and Mr. Müller – however, the court, lawyer, and expert costs have now risen significantly to €12,000 and initially remain with Mr. Müller. 

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