Skylights are an excellent way to introduce natural light into a building, reducing the need for artificial lighting and creating a more comfortable and welcoming environment for occupants. However, concerns about the thermal performance of skylights have led some building professionals to avoid their use. This blog will explore the thermal performance of skylights and demonstrate how they can contribute to meeting B3 building codes and LEED certification.
Thermal Performance of Skylights
Commercial buildings can use skylights to provide natural daylighting without decreasing thermal performance by selecting skylights that have good insulation properties and are designed to minimize heat gain and loss.
The thermal performance of skylights is determined by their U-factor, Solar Heat Gain Coefficient (SHGC), Visible Transmittance (VT), and Light to Solar Gain (LSG). The U-factor measures the rate of heat transfer through the skylight’s glazing and frame, while the SHGC measures the amount of solar radiation that passes through the glazing. VT measures the amount of visible light that passes through the glazing, and LSG compares the amount of visible light to the amount of solar radiation that passes through the glazing.
Skylights with a low U-factor are ideal for cold climates, as they allow solar radiation to enter the building and heat it up, reducing the need for artificial heating. Perfect for winters in the Midwest! In warm climates, skylights with a low SHGC are preferred, as they allow less solar radiation into the building, reducing the need for artificial cooling. However, it is important to strike a balance between the U-factor and SHGC, as skylights with a high SHGC can increase the building’s cooling load in hot climates, and those with a high U-factor can increase the heating load in cold climates.
AES Sunoptics Signature Series skylights’ specialized design removes some heat concerns by refracting sunlight evenly across the room, eliminating ‘hotspots’ and avoiding the need for skylight tinting, skylight insulation covers, skylight heat blockers or trying to find the best window film for skylights. The Signature™ Series Skylights are the best skylights on the market at capturing low-light levels due to their patented dome-shaped design. The product provides glare-free full spectrum natural light, free of UV-damage.
Of course, proper design, installation and maintenance of skylights can also help ensure optimal thermal performance over time.
Using Skylights to Achieve Sustainable Building Certifications
B3 Building Codes
A B3 building is one that meets the state of Minnesota’s B3 Guidelines for Sustainable Building Design and Construction. The B3 Guidelines provide a framework for achieving sustainable building design and construction, with a focus on reducing energy and water consumption, minimizing waste, promoting indoor air quality, and using environmentally friendly materials.
B3 building codes aim to improve the energy efficiency and sustainability of buildings. Skylights can contribute to meeting these codes by reducing the building’s reliance on artificial lighting and reducing the amount of energy required to heat or cool the building. Additionally, skylights can improve indoor air quality by introducing natural ventilation, which can reduce the need for mechanical ventilation systems.
To meet B3 building codes, skylights should have a U-factor of 0.30 or lower and an SHGC of 0.25 or lower. The use of skylights should also be carefully considered in relation to the building’s orientation and climate, as this will affect the amount of solar radiation that enters the building.
Similar to B3 building codes, LEED certification is a widely recognized standard for sustainable building design and construction. Skylights can contribute to meeting LEED certification requirements by improving energy efficiency, reducing the building’s carbon footprint, and promoting occupant health and well-being.
To contribute to LEED certification, skylights should have a U-factor of 0.50 or lower and an SHGC of 0.30 or lower. The use of skylights should also be carefully considered in relation to the building’s energy performance and lighting design, as this will affect the amount of energy required to heat or cool the building and the need for artificial lighting.
Skylights can provide natural light to a building without compromising its thermal performance. By carefully selecting skylights with appropriate U-factor and SHGC values, building professionals can contribute to meeting B3 building codes and LEED certification requirements. However, it is important to consider the building’s orientation and climate, as well as its energy performance and lighting design, when selecting skylights for a project. With careful planning and design, skylights can enhance the sustainability, energy efficiency, and occupant comfort of any building.
Want to talk to a daylighting expert about your next skylight project? Contact Daylight Specialists today!