Daylighting The Dark Areas
There are three ways to add natural light to a room, one of course is a window. But what if there isn't enough room for a good sized window, say in a closet or hallway? Well of course there is always a skylight option, (expensive!) but what about a solar tube? A solar tube or light tube adds plenty of warm indirect sunlight and is a fraction of the cost of a skylight. The light tube is also known as a “tubular skylight” or “tubular daylighting device/system”, and is the oldest and most widespread type of light tube used for daylighting. Daylighting is the controlled application of diffused natural light into a building’s interior, thus drastically reducing the use of electric lighting and therefore saving energy.
Lower Upfront Investment, Reduced Life-cycle Costs & Higher Return on Investment
Solar light tubes, compared to conventional skylight offer better heat insulation properties and more flexibility for use in inner rooms, and are more affordable to install. Use of daylighting systems equates to lower overall operating expenses for electricity, reduces expensive peak energy demand, longer replacement cycles for electrical fixtures (using hybrid models) and no maintenance requirements for daylighting fixtures. A hybrid daylighting solution is reported to cut lighting energy use by as much as 94%. Passive daylighting is 100% renewable, efficient and has no electricity cost associated with it. A light tube costs about $700, depending on whether or not you want a hybrid (combined with LED lighting), when professionally installed. This is a remarkable savings when it is compared to a skylight which may run around $2,000. There are also daylighting kit's available starting at around $255.00, if your handy and feel comfortable working on a roof - they can be installed in an afternoon. Specific daylighting systems are eligible for federal tax credits for energy efficiency building products.How It Works
A solar daylighting tube is a 10 or 14 inch in diameter sheet metal tube with a reflective interior. It captures daylight at the roof with a weather-proof, plastic, light capturing dome, and ends in a porthole-like diffuser in
the ceiling of the room below. The reflective material acts like a continuous mirror, channeling light along its entire length, and it preserves the light's intensity. The light it delivers is more intense than a skylight since it intensifies as it is channeled through the reflective tube. A 10 inch tube is the equivalent of three 100 watt bulbs, enough to illuminate up to 200 square ft. of floor area; a 14 inch tube can brighten as much as 300 square ft. Check out the picture at the right (and above) to see how well these daylighting tubes work. The Copper Box, the venue for Handball at the 2012 Summer Olympics, made use of light tubes reducing energy use.
Daylighting At Night
What about non daylight hours? There is a hybrid model available, the hybrid daylighting tube unit utilizes LED lamps, florescent, or incandescent bulbs to illuminate a building interior during non-daylight hours. The lights are either built inside the diffuser dome or adjacent to it. Some models automatically sense the change from day to night and automatically switch to the LED bulbs. There are also other uses for daylighting systems. One company offers a Ventilation Add-On Kit, which combines daylighting and ventilation into one fixture, leaving rooms humidity-free - such as a bathroom.* Studies have shown that people exposed to natural light are more productive, achieve a better sense of well-being, and are more positive.
(Home images from Solatube)
