As a building owner, you're always looking for ways to improve the tenant experience and manage energy expenses. Building enhancements are a smart way to accomplish both, especially when discussing an enhancement like daylighting.
As a building owner, you're always looking for ways to improve the tenant experience and manage energy expenses. Building enhancements are a smart way to accomplish both, especially when discussing an enhancement like daylighting.
"Daylighting is the controlled admission of natural light, direct sunlight, and diffused-skylight into a building to reduce electric lighting and sav[e] energy," explains Gregg D. Ander in Whole Building Design Guide. When daylighting a space, you take actions to harness the full spectrum of natural sunlight to minimize the number of hours electricity is needed.
But daylighting doesn't mean you need to install floor-to-ceiling windows everywhere. Daylighting truly is the practice of harnessing sunlight for its benefits, not its negatives. Too much sunlight can negatively impact the indoor environmental quality of the building. Thermal comfort and glare can hinder the building occupants' performance and reduce productivity.
A daylighting system is equal parts system, technology, and architecture. A comprehensive daylighting system should include strategic daylight apertures, like skylights and windows, and a daylight-responsive lighting system that can be easily controlled. Additionally, the location of windows must be considered and shades or blinds made available to remediate sun glare. Certain daylighting strategies may not be possible when retrofitting a building since one major component in daylight is the building's footprint.
The benefits of daylighting can be experienced in almost any climate, whether your building is located in the sunny South or often-overcast Northwest. Every building is a candidate for daylighting, too—schools, commercial office buildings, warehouses, shopping malls, hospitals, and gyms!
Leveraging daylighting instead of artificial lighting has been shown to improve the overall attitude, satisfaction, and wellbeing of building occupants. Specifically, daylighting has been shown to:
"By providing a direct link to the dynamic and perpetually evolving patterns of outdoor illumination, daylighting helps create a visually stimulating and productive environment for building occupants," adds Gregg D. Ander.
No electric light can compare to the quality of natural daylight. At a color rendering index (CRI) of nearly 100, daylight areas can reveal various items' "true" colors without the disturbance from electric light flicker. High CRI light is desirable in color-critical applications such as neonatal care, landscape architecture, architecture, and graphic design.
As a result of improvement in the indoor light quality, studies have shown that daylit areas generate more shopper traffic resulting in more sales in big box and retail stores. When you're a building owner, that information may not directly benefit your bottom line. However, it does support your tenants and their businesses, and help them maintain operations in your facility.
Also, consider that buildings with more windows tend to rent for more than those that do not. In "The Benefits of Daylight Through Windows," scientists at the Lighting Research Center found anecdotal evidence that commercial real estate with no windows leases for about 20 percent less—or $2 to $4 per square foot less—than spaces with windows.
Turning off more lights during the day can allow facilities to take a "greener" approach to day-to-day operations and reap the energy-saving benefits of daylighting.
According to the U.S. Department of Energy, "electric lighting in buildings consumes more than 15 percent of all electricity generated in the United States."
However, by simply outfitting a space with daylight-sensing controls, you could reduce the energy used for electric lighting by 20 percent to 60 percent, finds the Building Research Establishment.
Using daylighting correctly can lead to noticeable cost savings. Facilities Net estimates that "a good daylighting design can save up to 75 percent of the energy used for electric lighting in a building," leading to a lower energy bill. Electric lights also generate heat. By turning off or dimming lights more often, you could further reduce the energy used to cool a building by 10 to 20 percent, adds Facilities Net.
Any building can be daylighted, but different strategies apply depending on whether you're designing a new building or retrofitting an existing one.
For new buildings, consider the following during the design process:
Depending on your budget and goals, you may be able to take advantage of some of the above daylighting strategies. For existing buildings, however, you may find it easier to:
If you're learning about daylighting systems for the first time, especially skylights, you may come across some new terminology. We've outlined these terms below.
Visible Light Transmittance (VLT) – The amount of light in the visible portion of the spectrum that passes through a glazing material.
Solar Heat Gain Coefficient (SHGC) – Measures how well a skylight blocks heat from sunlight.
U-Value – Measures the amount of heat transfer through a skylight and tells you how well the skylight insulates.
Transmission Haze or Diffusion – Measures of the light scattering characteristics of a material.
Effective Skylight to Floor Ratio (ESFR) or Skylight to Floor Ratio (SFR) - The percentage of the total square footage of floor area covered by the total square footage of skylights in the roof.
At Elevate, one of our goals is to help our customers conserve energy by maximizing the number of hours their electric lights can be turned off. A cost-effective way to achieve this is to use rooftop skylights to daylight a space and harness the full spectrum of natural sunlight. We have a very diverse portfolio of Skylight solutions to service any project. Contact your local Elevate representative to learn more.
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