What are Tubular Daylighting Devices (TDDs) and How Do They Work?
Natural daylight has been proven to increase office workers’ performance and productivity. Tubular daylight devices (TDDs) use a rooftop dome to capture the sun’s rays and transmit them inside a building, bringing natural sunlight – minus the harmful ultraviolet and infrared rays – into the gloomiest of indoor spaces. A properly designed tubular daylight system can dramatically improve interior lighting quality while reducing dependence on artificial light. But have you ever wondered how they work, and whether they would be a good fit for your commercial space? As a passive daylight device, a TDD requires no electricity to operate during daylight hours — making it one of the most energy-efficient lighting upgrades available for commercial buildings.
A Little Space for a Lot of Light
Tubular daylight devices’ compact size – from 14” to 29” in diameter in commercial buildings – makes them easy to install and they occupy very little space in most roofing systems. Each tubular daylighting device is engineered to fit within tight ceiling cavities while delivering a consistent, high-quality light output. The dome’s curved shape means it catches sunlight from all directions, which is then transmitted inside the building through highly reflective tubing, bringing beautiful, natural daylight into your interior space through a highly efficient tubular daylighting system.
Sunshine Underground
The best TDDs out there can transmit daylight deep into a building’s darkest recesses – reaching areas beyond the wildest dreams of even large commercial skylights. This can be achieved due to the highly malleable nature of their reflective tubing, which can be bent to create “elbow joints” along the way. In this way, a tubular daylighting system can maneuver around most obstacles in the building plenum space – such as plumbing, HVAC, or electrical – and transfer the light across multiple rooms through diffusers. The level of light in a room can then be controlled with dimmers or supplemented with electric light, as needed. TDDs can deliver liveable levels of sunlight across tube lengths of 100 feet or more, which is why many architects specify commercial tubular daylighting devices in large-scale projects.
Solatube tubular daylighting system image showing a rooftop dome connected to a highly reflective tube and ceiling fixture, illustrating how sunlight is captured and transferred into interior spaces.
Sunshine For All Seasons
Unlike commercial grade skylights, TDDs draw the sunlight inside your building, and they simultaneously repel the full intensity of the heat these rays bring with them. How is this possible? The dome uses a Fresnel lens design to draw the light inside. It’s also worth noting that a TDD won’t interfere with air conditioning, because of their multiple layers of glazing, providing thermal protection. On the other hand, in a freezing Midwest winter, TDDs’ minimal size and incursion of a building mean they cause nominal heat loss, compared to commercial skylights. And unlike commercial skylights, TDDs are leak-proof! This makes them an excellent option for facilities considering a tubular daylighting system in North Dakota, where seasonal temperature extremes demand high performance and durability.
Additional Benefits of Tubular Daylighting
Beyond performance and efficiency, tubular daylighting devices offer long-term value for commercial property owners and facility managers. By reducing reliance on artificial lighting during peak daylight hours, businesses can lower energy consumption and operating costs while supporting sustainability initiatives. Improved indoor lighting quality can also enhance employee comfort, reduce glare, and create more inviting spaces for customers and staff. Because these systems require minimal structural changes, installation is typically faster and less disruptive than traditional skylights. Whether upgrading an existing facility or designing a new commercial building, tubular daylighting solutions provide a practical way to introduce consistent, controlled daylight into interior environments that would otherwise depend entirely on electric lighting. Choosing the right daylighting system depends on your building’s size, roof structure, and interior layout — and Daylight Specialists can help you evaluate the best fit. Daylight Specialists offers a range of the highest quality tubular daylighting device and other daylighting solutions on the market. We are happy to answer any questions you have about TDDs and to talk you through the options that would best suit your commercial spaces. If you are interested in learning more about TDDs, we offer an AIA-accredited presentation, “Introduction to Tubular Daylighting Devices (TDDs),” that we can present to your team. Reach out to us today for more information!