Maintaining Balance
In working with daylight, the primary objective for architects is to achieve the proper balance. “Our goal is to get uniform light deep into academic spaces so that there are not any bright spots, dark spots, or glare,’’ Wernick said. “We try to design for uniform light within the learning space.”
Site orientation is one of the most crucial factors architects consider. “We are always trying to make sure we’re designing the school in context with the site. We also don’t want to cause huge disturbances on the site. We try to get as close to north-south orientation as we can with as many of the classrooms as we possibly can.”
Other factors also determine optimal balance. A gymnasium or a swimming pool, for instance, will have fewer windows to reduce glare that may disrupt competition. Science labs might have different lighting needs than the student library.
The complexities can be far-reaching. In the project at Kean University by NK Architects, the Liberty Hall Academic Center includes spaces for research, teaching, archiving, preservation, gallery display and a flexible exhibit hall. Some exhibits include fabrics from the Colonial era, which could be harmed by sunlight. “We do have natural light, but we used a Bendheim product that was a fairly opaque glass. It was very filtered, but it’s still natural light,’’ Lewis said.
NK Architects selected light-diffusing textured channel glass with a low-e coating, interspersed with clear glass channels used as vision lites. The thermally coated channel glass achieves U-Value of 0.41, while maintaining daylighting advantages with approximately 64 percentp VLT (visible light transmittance). The low-e coating creates a subtle iridescent appearance, a feature unique to the three-dimensional glass material.
Thermal performance is also critical. The interplay between light and thermal efficiency—especially in extreme climates—is a difficult balancing act. “Daylighting and thermal comfort are very, very closely interwoven,’’ Wernick said. “We have design strategies to get natural light into the classroom, but we have to also be thinking about thermal control and comfort at the same time.”
Architects have to consider the upfront cost of the project, as well as the impact of material selection on the thermal performance and energy costs after the building is completed. A more costly architectural choice during construction may dramatically reduce operational heating and cooling costs. In other words, clients can pay now or pay later.
“Sometimes you give those things consideration as quickly as you can,’’ Lewis said. “It’s a lot easier when a client says they can’t afford it right at the beginning. There’s a lot of nuances involved and a million different things to balance the budget. You have to have those deep conversations.”