Glint and glare report

A glint and glare report is used in the planning process to clarify in advance whether complaints about unacceptable sunlight reflections may arise later after the installation has been erected. Since subsequent anti-glare measures can be very expensive and usually lead to yield losses due to shading, it is advisable to exclude such risks already in the planning phase.

In any case, authorities are now increasingly demanding an expert opinion on glare before granting planning permission.

Who can be dazzled?

Glare can blind vehicle drivers in (road, rail and air) traffic to such an extent that they are not sufficiently able to react to dangerous situations. Of course, drivers are responsible for adapting their driving to the visibility conditions (e.g. glare on rain-soaked roads), but reflections of sunlight on sloping surfaces can occur completely unexpectedly. A surface that just appeared as a dark, somewhat iridescent plane can suddenly become an optical fireball that completely takes away visibility when driving on at a certain angle of view.

In residential and working areas, sunlight reflections are considered immissions in the sense of the Federal Immission Control Act (Bundes-Immissionsschutzgesetz), which can be unacceptable for those affected if they persist for a longer period of time.

What criteria must an expert report on glare fulfil?

There are no standardised criteria for glint and glare reports. It “only” has to fulfil its purpose, which is not only to obtain planning permission, but also to increase investment security by ensuring that no unforeseen glare protection measures are required after the installation has been erected.

Since 2007, Solarpraxis has already prepared more than 250 glint and glare reports and networked with other glare assessors years ago for quality assurance and the exchange of professional knowledge. One result of this was the lecture “Glare reports on photovoltaics – a status report from expert practice”, which was heard for the first time at the OTTI Symposium in 2014. Since April 2017, Wolfgang Rosenthal has been publicly appointed and sworn in by the Berlin Chamber of Industry and Commerce as an expert for glare caused by reflected solar radiation (especially in photovoltaic systems).


Wolfgang Rosenthal
ÖbuV – Expert
+49 | 30 | 726 296 – 350