9 Things to Consider When Selecting High-Performance Skylights
High-performance skylights can be a functional and valuable addition to a commercial or industrial space, creating a well-lit, productive, energy-efficient environment by harnessing the sun's power. But skylights aren't a one-size-fits-all building component. Skylights must be tailored to each commercial or industrial space.
How to Choose a Skylight
Various factors go into selecting a skylight for a commercial or industrial space. Choosing the right one is critical to maximizing product performance and reducing maintenance or replacement costs.
The U.S. Department of Energy (DOE) notes that the size of a skylight affects the temperature and illumination in the space below. Generally, the DOE says, the size of a skylight should never exceed 5% of the floor area of a space with many windows or 15% of the floor area of a room with few windows.
You can take a page from the residential sector for help determining skylight size. SFGate, formerly the San Francisco Chronicle, recommends estimating skylight size in the following way.
"If the room has few windows and generally is dark, multiply the square footage by .15. If the room has an average number of windows and is neither well lit nor dark, multiply the square footage by .10. The resulting number is the approximate square footage for the appropriate size skylight for that room."
Common shapes of skylights include circular, diamond, multi-sided, oval, rectangular, triangular, and tubular, according to the DOE.
Tubular skylights, for instance, usually are smaller than many other skylights. The roof-mounted light or solar collectors on tubular skylights can boost the potential for daylight streaming into a space while reducing heat buildup in the summer and heat loss in the winter.
3. Energy Efficiency
Utilizing natural sunlight is a more energy efficient option than artificial lighting generated by electricity and fossil fuels.
Plus, skylights employ various glazing techniques, some of which can improve energy efficiency. For instance, manufacturers incorporate techniques such as heat-absorbing tints, insulated glazing, and low-emissivity (low-e) coatings to make skylights more energy-efficient. These glazings can help minimize the rise in summertime heat or the decrease in wintertime heat.
When shopping for a commercial or industrial skylight, see whether it carries an energy performance rating from the National Fenestration Rating Council (NFRC). Sustainability, including energy efficiency, is one of the most important considerations when selecting a skylight.
Aside from letting in natural light, a skylight may be able to provide ventilation. Ventilation can enable the release of hot air that typically rises toward a ceiling. Ventilating skylights generally open outward at the bottom, the DOE notes.
Some skylights might not permit ventilation. For instance, tubular skylights don't offer ventilation or views of the outdoors.
5. Climate Zone
Your building's climate zone will help dictate what kind of skylight you purchase or specify. Check this climate map from Energy.gov to find your zone. If the skylight is for a building in a colder climate, for instance, you'll want to pay attention to how well the skylight is insulated.
6. Wind Load
Along with the climate where a skylight is being installed, give thought to the wind load. In a hurricane-prone place like Florida, the wind-load requirement for a skylight will be more strict than in an area that doesn't experience hurricanes.
7. Hail Rating
A region's likelihood of experiencing hailstorms also plays a part in choosing a skylight. In hail-prone states like Kansas, Missouri, Nebraska, Oklahoma, and Texas, a skylight needs a higher hail rating than in states where hailstorms aren't common, such as Arizona, California, Nevada, Oregon, and Washington.
8. Insurance Standards
A building's adherence to FM Global insurance standards also is a factor in selecting a skylight. We offer four FM Global-approved skylights: SunWave (polycarbonate), single-glazed, double-glazed, and curb topper.
An FM approval is one you can trust. As wind expert and former Clemson University, Dr. Peter Sparks says, "There has not been a hurricane in North America in the last 25 years which would have damaged a building constructed in accordance with FM Global design guidelines."
- FM-approved skylights have been subjected to:
- Fire tests to determine their ability to limit flame spread and the likelihood they will melt and drip.
- Hail simulation tests with freezer ice balls to assess their ability to resist breaking from the impact of hail.
- Wind resistance tests to determine their ability to resist wind forces on a roof system.
Before purchasing a skylight, review the warranty offerings.
A range of warranties are available through Elevate. For instance, a limited warranty for a SunWave skylight can last five, 10, or 20 years, while a limited warranty for a Velux skylight can be good for one year, three years, five years, or 20 years.
Are Skylights a Good Idea?
Now that you know some important factors that go into buying a skylight, are skylights worth it? Ultimately, that's for you to decide. High-performance skylights can be part of an overall daylighting strategy to reduce electric lighting and save energy.
Here are four pros and cons to help inform your decision.
Among the pros are:
1. Reduced heating, cooling, and lighting costs if a skylight is properly selected and installed.
2. A skylight can provide much-needed ventilation during the warmer summer months.
3. Skylights can contribute to the overall sustainability of a building. One study out of the University of Colorado at Boulder indicated that artificial lighting makes up 25% to 40% of energy consumption in commercial buildings.
4. Exposure to natural light can help boost building occupants' moods and promote feelings of better health.
5. Potential energy savings and tax credits might help offset the upfront expense of skylights. The Commercial Buildings Energy Efficiency Tax Reduction (EPAct 179D) has become a permanent Tax Savings opportunity for building owners. EPAct 179D offers building owners a $1.88 per square foot tax deduction for the entire footprint of the roof, not just the area covered by skylights. Visit Energy.gov for details on taking advantage of this tax savings opportunity.
Among the cons are:
1. During the summer, a skylight may generate more heat from sunlight. Placement of a skylight on a north-facing roof can minimize this impact, though, as well as installation of skylight shades.
2. In the winter, glass in a skylight might allow warm air to escape. Fortunately, choosing a skylight with a low-e coating can help trap warm air during the winter.
3. Exposure to natural sunlight might fade furniture. Skylights that block nearly all UV rays can help combat this.
4. Skylights are an investment and can add to a building's construction and maintenance budget. Ongoing tax credits can help offset this initial investment.
Elevate SunWave™ Domed Prismatic Skylights leverage the power of the sun by maximizing visible light penetration, with 100% diffusion, to disperse the optimum amount of glare free, natural light inside a building while reducing dependence on artificial lighting during daytime hours.
Get in touch with your nearest Elevate sales representative for help selecting the best skylight for your building and more daylighting strategies.