Having access to natural sunlight can do more than let occupants keep their lights shut off for most of the day; daylighting can even impact the mood and well-being of everyone indoors.
Below, Russell Ibotson of VELUX Canada explains how light tubes can be used to cut down energy usage and give indoor spaces without windows access to natural sunlight.
What are light tubes, and how do they work?
Light tubes, also call light or sun tunnels, all refer to tubular daylighting device, or TDDs as referred to in Canadian building codes.
A TDD is a type of skylight that brings daylight into a home or other space in need of more daylight. It comprises of three main components: the glazing system at the roof, the diffuser system at the ceiling and the highly reflective tunnel connecting the roof to the ceiling. Daylight enters at the roof level, bounces down the reflective tunnel and enters the room through the ceiling. The tunnel design can also maneuver through trusses.
What benefits can light tunnels bring to a building?
Light tunnels bring in high quality daylight that electric lighting cannot match. This reduces the need for electric lighting, and can lower the building’s energy load a little bit.
But more importantly, light tunnels can improve the indoor environment, and have a positive impact on occupants’ mood and productivity. The tunnels can also effectively bring daylight to spaces that do not have access to an external wall for a window, or an appropriate roof or attic for a traditional skylight.
The biggest benefit these tunnels bring is a brighter space with more daylight. This adds value to a property owner, since daylight is more comfortable and brings a small connection to the outside world. While light tunnels can’t offer certain benefits that tradition skylights can bring, such as a view and fresh air, they are less expensive to install and may be more appropriate for walk in closets, bathrooms and halls within a building.
Are light tubes just for residential buildings, or can they be installed in commercial properties?
While many light tunnels are for residential markets, companies can work with architects designing institutional, industrial and commercial projects to install light tunnels. They can be made to accommodate flat roofs, drop ceilings or open ceilings.
Are light tunnels installed during development, or can be they retrofitted in?
Light tunnels are primarily a renovation product. Companies are updating the design and accessories to accommodate the energy efficiency and air tight requirements of new homes.
Light tunnels can work within existing truss spacing, flash simply into the roofing material, sloped or flat, and accommodate standard ceiling finishes. Thermal and air breaks are both at the ceiling, so one does not have to insulate the tunnel.
Are there any incentives to install light tunnels?
There are several LEED (Leadership in Energy and Environmental Design) points that owners can apply light tunnels to. The categories include energy optimization, daylighting, controllability, and weather impact sections. They can also be applied to the Active House specification in Europe and other daylighting metrics.
Has interest in light tunnels grown in recent years?
The interest in TDDs continues to grow. People are living in tighter communities, and row housing and townhouses are becoming more common. Even single homes are so close together that little daylight is available through side windows. Humans’ primal desire for daylight leads the charge, and TDDs are possibly the most accessible way to add daylight into the core of a building or home.
The National Building Code of Canada has listed TDDs since 2010, and the Ontario Building Code will cover TDDs starting in 2014. This will give code officials the necessary reference to approve TDDs in new construction, which means more new homes will start incorporating them into the design.
Russell Ibbotson is a professional engineer with VELUX Canada and has more than a decade of experience in the building industry. At VELUX, Ibbotson has been tasked with inspiring and guiding builders and architects to identify opportunities to enhance living spaces through the use of daylight and fresh air through their roofs.