To make the churches, castles and monuments illuminated in such a way to be as cost-effective as possible and as less disturbing to nature as possible.
Light at night can have negative consequences for humans and animals who have adapted to the rhythmic exchange of light and darkness in the millennia of evolution.
The project "Life at Night - Improving the Conservation Status of Nocturnal Animals (Butterflies and Bats) by Reducing the Effect of Artificial Lighting at Cultural Heritage Sites" (LIFE + program) has sought technical solutions to more properly illuminate cultural heritage. They have developed a new type of reflector that is tailored to the shape of the building and reduces unnecessary light to the sky.
New reflectors for nature-friendly church lighting feature a special aperture that is tailored to the shape of the building and prevents light from shining past the facade into the sky. On the lamp is a mask with a silhouette of the church (made from photographs of the facades of the churches), which prevents radiation into the sky. A UV filter is also installed as the UV light attracts night insects the most. New lighting is not only friendlier to nightlife, but also less wasteful.
Although road lighting is a major contributor to light pollution, lighting of cultural objects is a particular problem. Only in this case is lighting from the bottom up allowed, as it is often not appropriate to install lamps on historic buildings. Because conventional lamps are not specifically adapted for this purpose, much of the light goes past the facade into the sky where no one needs it.

Resources needed

Some 9000 EUR for 13 new lights, removal of redundant lights (site does not need as many lights as before). The lights use max. 150 W light bulbs instead of 400 W light bulbs.

Evidence of success

At the initial illumination, up to 80% of the light was passed past the facade into the sky and the surrounding area, and with a tailored lamp, the light beam was reduced to about 2%, which is much less than 10%, as permitted by Slovenian legislation. The brightness of the façades of the buildings has decreased from more than 7 cd / m2 to below the legal limit of 1 cd / m2. In addition, electricity consumption decreased by an average of 65%, in some cases up to 90%.

Difficulties encountered

Replacements were made in consultation with parishioners, priests and individual parishes, with an agreement to reduce the number of luminaries. For the protection of nightlife, it would of course be best not to light the facilities at all. So, turning off the lighting after 23:00 is a compromise.

Potential for learning or transfer

Two publications (brochure and leaflet) were published with recommendations for more environmentally friendly lighting of cultural heritage objects and easier transfer of good practice. They present the issues of light pollution, legislation in this field, the results of project research on nocturnal animals, and recommendations aimed at lighting operators of cultural heritage objects.
Given that technical guidelines were drawn up together with UNESCO, it is expected that this cooperation is also the first step towards international standardization in the field of lighting of cultural heritage objects.
Light pollution and the decline of biodiversity are interrelated global problems. So, it is important to inform the environmental and nature protection organizations about the project's achievements. In this way, we want to encourage the implementation of the recommendations at European and international level.

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Main institution
Društvo Temno nebo Slovenije
Zahodna Slovenija, Slovenia (Slovenija)
Start Date
September 2010
End Date
February 2014


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