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The Largest Archaelogical Museum, The Grand Egyptian Museum, is now open! --> Read about flagship project

More Light,
Less Heat. 

Save up to 30% on energy costs with

research-backed louver technologies 

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glare-free

low-to-no maintenance

retrofit or new building

Demonstrated results around the world 

Proven expertise with 6,500,000 sf

of completed

projects in

11 countries

save on your property operating expenses

85% less heat transmission than standard blinds, up to 50% less reliance on artificial lighting 

cooler in summer,

warmer in winter

Passive system effective year round, custom-designed

for each individual project

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Our flagship project: the Grand Egyptian Museum is now open!

170,000 m2 Exhibition Area
5 Million Visitors Yearly
€1 Billion Construction Cost

100,000 Artifacts

proven success in flagship projects across 11 countries

Advancing the Daylighting Frontier

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Köster Lightplanning has partnered with leading research institutes to advance mirror-optic reflective blind systems. We’re now seeking pioneering collaborators for the next gen of daylighting — on real buildings to quantify daylight gain, comfort, and ROI.

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6.5M

square feet of demonstrated projects around the world. 

11

Countries with RETROSolar projects implemented. 

35+

Years of experience implementing daylighting systems.

5%

Achieving the lowest G (SGHC) values across our product lines.

The future of daylighting technology:
mirror optic 
louver systems.

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productivity, performance
& well-being

RETROSolar delivers balanced, glare-free daylight deep into the floorplate so people can focus longer and feel better.

 

In a study by Paracelsus Medical University, classrooms with RETROLux A blinds showed up to 30% lower cortisol and more efficient melatonin breakdown versus standard external venetian blinds—biomarkers linked to lower stress and better sleep. That translates to sharper attention, fewer headaches, and measurably better days at work.

  • Glare-free daylight on task planes

  • Comfortable brightness across the whole floor

  • More “prime” workstations, not just at the windows

pays for itself—
four ways

RETROSolar systems cut lighting hours, slash heat at the facade, and smooth peak loads—while making space more desirable. Every project is modeled with our proprietary software that accounts for climate, orientation, schedule, and region, and the optics can be fine-tuned after installation for maximum ROI.

  • Lower lighting energy

  • Lower cooling loads (better g-value/SHGC via retro-reflection)

  • Lower peak demand

  • Higher asset value (happier occupants, stronger leasing)

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how the optics work

We design precision mirror optics to redirect useful daylight upward and deep into the room—while “sending back” excess solar energy. Compared to conventional blinds, the optics can reduce solar heat input by up to 80% and simultaneously boost diffuse, glare-free illumination—bringing offices closer to daylight autonomy.

  • Significantly improved g-values through RETRO reflection

  • More diffuse, natural light with no screen washout

  • Software-tuned louvers for ongoing performance optimization

Frequently Asked Questions

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