Solatube International - Natural Daylighting through Sun Tunnels for your Home or Business (Video)

Posted by: Rate It Green Team

If you aren’t aware of daylight or sun tunnels, or you want to know more, join green builder Matt Hoots as he speaks with Dr. Neall Digert, Vice President at Solatube International to learn more about Solatube’s technology and how sun tunnels work, as well as the benefits of these systems.  This video is a great 101 introduction to daylighting benefits and also provides a 201 level explanation of how these optical systems work.  
 

Natural daylighting is an essential part of a productive work environment as well as a comfortable, well-lit home.  Sunlight doesn’t run out, and it’s thankfully energy-cost-free in contrast to lights.  Windows and skylights have traditionally been used to bring natural light into interior spaces, but tubular daylighting devices, or TBDs, harness and transfer light without consuming electricity and also without adding cooling load or contributing to heat loss.  Solatube’s optical systems collect or “harvest” daylight through a building, and deliver that light to an interior space through a fixture.  Solatubes function like a regular light, but they deliver daylight without consuming electricity.  Through a daylight chase or tubing light guides, Solatubes can duct daylight anywhere in to a building, much like we can direct air though HVAC duct work. 
 

Image: The Solar Guys

Dr. Digert has a background in optics, daylighting, building energy and also importantly, human psychology, physiology and neurochemistry, so he really understands the benefit of natural lighting, and how Solatube's technology delivers.  According to Dr. Digert, he specializes in "designing spaces that make people happier and healthier.” 
 

To understand the benefits of a Solatube systems, it’s key to understand that windows and skylights products create an additional cooling load for a building’s air conditioning system or a greater need for heating in the winter due to heat loss - Solatubes eliminate heat and reduce potential for heat loss out through the product.  
 

Not only are Solatubes energy efficient, but they are light selective. In other words, they transmit only the wavelengths of energy that are positive for building occupants.  All wavelengths of visible light are present all of the time, which is key and is why daylighting is the reference source by which all lighting systems are compared.  LEDs might be energy efficient, but their light is static, unchanging.  Real daylight, however, is dynamic and constantly changing.  Our bodies are designed to perceive real light as a time keeper, to produce neurotransmitters and hormones and regulate other cycles as part of a cyclical process within our 24-hour clock. How the 24 hour exposure to light affects our human physiology and biological processes is known as chromo biology.  According to another concept called chromo spectral dosage, our bodies also crave different spectral content at different times of the day.  When we remove people from the time dependent special content of daylight, we can see issues with attention deficit disorder, depression, and other common ailments.  These concepts describing the rise and fall of light levels, as well as the content of light, help us to attain just a beginning understanding of how natural light reinforces, informs and really drives the body, and makes people healthier, physically as well as psychologically.  

Image: Solatube International

Apparently, 80% of our brains are dedicated to processing the environment around us.  In a lightless environment, people don’t experience the passage of time in the same way, missing a stimulus that literally keeps us awake.  Brains then naturally shut down to some extent to conserve energy and protect the body.  This is true for workers in an office as well as students studying at school. Without natural light, teachers have to work harder to get kids to engage - daylighting can help wake the kids up so teachers can focus more on teaching and less on entertaining.  More engaged and alert students can then learn subject matter more efficiently.  The same is true for employees.  Mentally engaged and connected employees are apparently 6%-16% more productive with proper daylighting.  More alert and comfortable employees feel less of a need to get up, walk around, and wake themselves up by chatting or making a coffee run.  This extra productivity translates directly to the bottom line. 

Solatubes can be placed with a high level of consistency within a designed space, bringing all of the benefits of daylight tunnels, but allowing an architect or designer to place lights consistently.  So the tubes are not only great for spaces without natural light, but they are also good for perimeter spaces and offices that have windows - they can help minimize contrast ratios and reduce or eliminate flare, reducing the need for blinds and controls.  Solatubes can be effectively applies across all building sectors - residential, commercial, industrial, and institutional. They are available recessed, flush mounted, can also become an architectural feature of the space. The idea is to give the designer and the end user the ability to express themselves.  Designers can also just the specific look and feel of Solatube products, choosing the diffusion level to mask or show the view to the outside, and to adjust the level of visual connection to what they feel will make the best connection or happiest for occupants.  The tubes can look more like traditional electric lighting, or the occupant can look up and see the view to the outside in the fixture (cool).  
 

Images: Solatube International

Solatube has worked with the National Fenestration Council for more than 20 years; all products are tested to all fenestration standards and the company provides data on solar heat gain, U-Factor, visible light transmittance, and air filtration ratings. Solatubes are multi-glazed fully sealed systems - there is no thermal conductance from outside in or from unconditioned spaces like attics to conditioned/occupied spaces of the building, no air infiltration or exfiltration.  The systems only allow visible light, but not other wavelengths.  Even the optical tubing is not a mirror - any heat that makes it though a rooftop aperture will get absorbed at the very top of the system, isolating heat gain or loss at the insulation layer. This is what makes them so efficient.  Dr. Digert shares an example that in California a warehouse might be designed with 6% lighting or windows normally.  But Solatubes can light the same space with a 1% aperture area - and extract the heat out of that 1% - while adding no cooling load, and lowering the heat gain of an aluminum light by 2/3.  

Solatubes use a small aperture to collect a vast amount of daylight, more than a skylight or window per the same sized space.  They collect and concentrate this light and transport it into the building, in real time.  But what about when occupants don’t want as much light or when it’s not day time? Dr Digert explains how the tubs can be dimmed with low voltage controls or switches, from 100% to .5% (1% is good for emergency egress - and is recommended for schools), the same controls that would used for electric lighting.  The systems can also be run by solar power.  When more light is needed, highly optimized LED kits can be integrated to provide equivalent illuminations levels at night, also dimmable, and also run on low voltage control systems or wall switches.

Image: Solatube International   

Matt and Dr. Digert have a pretty robust Q&A at the end of the video.  Among other concepts already delineated above, we learned that Solatubes are completely compatible with passive houses and zero energy homes.  Solatube can also provide support and assist with energy and light modeling calculations.  We also learned that Solatubes can typically be installed within 2 hours for a residential application - wow.  
 

Do you have questions about Solatube daylight tunnels?  Have you installed a daylight tunnel an want to share your example as an inspiration for others?  Let us know, and post your comments below, or feel welcome to start a new post.