Most people come to the Grand Rapids Public Museum expecting to learn about history, science, and culture. But they might not realize the museum also has to function like an engineer, an architect, and a preservationist. A recent project focused on one of our most beloved features, the historic carousel, shows exactly how those skills come together.

For years, the carousel pavilion’s dark-tinted glass made it hard for visitors to see the carousel from the outside. Inside, it felt dim despite the space being surrounded by windows. Even more concerning, the existing glass let in enough UV and visible light to slowly damage the carousel’s paint and finishes, shortening the lifespan of the hand-painted details that make it special.

To address this, we evaluated three modern glazing options that would allow more daylight to enter, block harmful rays, and enhance the building’s energy efficiency.

Glazing Opportunities

The original glass allowed just 7% of visible light through, barely enough for someone walking by to know what was inside. But despite its dark look, it still let in a surprising amount of UV and visible light, both of which can cause fading and surface damage over time. The space also lost energy through the glass, increasing heating and cooling demands.

Before the renovation, a UV monitor inside the pavilion measured 379 UV PM per lumen. This metric represents the amount of ultraviolet radiation in microwatts relative to the amount of visible light in lumens. It is used in museum settings to evaluate the amount of damaging UV light present for each unit of useful daylight. A reading that high confirmed the risk to the carousel’s finishes and surfaces. After the glazing upgrade, the UV level dropped to just 8 UV PM per lumen, representing a 97% reduction, which brings the environment well within conservation standards.

We needed a solution that would protect the carousel, bring in more daylight, and operate more efficiently throughout the year.

The Glazing Options We Considered

Viracon, a leader in high-performance glass, manufactured all three of the glazing options we studied. Each option provided clearer views and better protection, with differences in insulation, energy use, and daylight levels.

Option 1 offered a significant improvement in daylight and visibility, with 64% visible transmittance and UV protection under 1%. It improved insulation and reduced energy use by over 14 percent compared to the existing glass.

Option 2 had nearly the same visual clarity as Option 1 but performed slightly better in terms of insulation and cost savings. With lower solar heat gain and strong UV protection, it offered a balanced solution for both preservation and energy savings.

Option 3 used triple-pane glazing and offered the best energy and emissions performance of all three. However, it introduced some drawbacks, including slightly lower daylight levels and a more complex assembly. Given the priorities of this project such as daylight, preservation, performance, and simplicity, Option 3 offered marginal benefits at higher cost and complexity.