Perspectives: Lighting Trends and the Building Environment
By Henry Cantwell, AIA, Niles Bolton Associates
Lighting is a critical component to the indoor environment. Proper lighting creates a comfortable and relaxing environment in the home and allows for increased productivity and job satisfaction in the work place. However, the energy costs incurred from lighting is a large part of the overall building cost. HESM&A, an Atlanta-based LEED consulting firm, has reviewed the most recent energy models, and it estimates that lighting accounts for as much as 25 percent of a building's energy cost and 8.8 percent of a household's costs. Because energy codes are requiring enhanced performance levels, major shifts in lighting technology and lighting design are occurring.
In institutional and office environments, for example, the incandescent lamp has completely disappeared. Only in residential settings are incandescent lamps still popular. Even the T12, the one-time workhorse of the fluorescent-tube industry, is being phased out in favor of more efficient super T8s and the T5. The T12 has an efficacy of 60 lumens/watt compared to the T5 at 70 lumens/watt. Lighting designers are constantly looking for methods to improve lighting applications, including using the ceiling as a reflector to spread the light more effectively, thereby calling for fewer fixtures. Additionally, the use of task lighting has become more popular, enabling
lighting levels to be supplemented where needed. Along with maximizing daylight, these two design solutions have produced environments with less fixtures and increased energy savings without sacrificing comfort and productivity.
However, these strategies are lagging in the residential marketplace. Daylighting continues to be a central option, but incandescent lamps are still the most preferred. Despite their low energy usage, fluorescent fixtures are strictly used for utility applications.
Some reasons preventing the fluorescent lamp from gaining widespread use at home are cost, color temperature and the delay in achieving brightness. While the initial cost of fluorescent lamps (including the screw-in replacement lamps) is 8 to 10 percent more than the typical incandescent lamp, the longer life and less energy use (75 percent reduction) will save in the long run. Color and temperature options are also expanding, providing customers with varying options.
With the increase of color temperature options and the recent spike in energy costs, many homeowners are now considering screw-in fluorescent lamps as replacements for incandescent. And thanks to a new government policy that will prohibit the sale of incandescent fixtures with low performance ratings, we will begin to see a far greater use of fluorescent lamps in the home. For those who are partial to incandescent light, Halogen is still an option, although users should be aware of the heat issues. General Electric has announced the development of a high-efficiency incandescent lamp, which is expected to be four times as efficient as the current incandescent
technology with an efficacy of 30 lumens/watt (comparable to compact fluorescent lamps).
The Light Emitting Diode (LED) technology is also gaining ground. They are currently used in applications such as traffic and car lights and architectural decorative lighting, but new technology is moving them into home and office use. Some advantages include efficiency, long life, color temperature and energy savings, which are typically 80 percent greater than incandescent and 30 percent greater than compact fluorescents.
Since LEDs are a solid state, they have a long life. The estimated average is approximately 40,000 hours. Also, they can be dimmed more cost effectively than fluorescent, they don't generate the heat that incandescent or fluorescent lamps produce, and they don't have the mercury issues that fluorescent lamps have. A few drawbacks include cost and light spread or point source. However, as the technology becomes more widely adopted, cost will come down.
It is clear that lighting technology is constantly being invented and re-invented to increase efficiencies and reduce energy cost. Lighting designers are using these technologies in conjunction with daylighting to create ways to reduce fixture counts while maintaining the required lighting levels at the task surface. Whether in the work place or the home lighting is will always play a part in how we view our spaces. It will continue to evolve, but the goal of creating comfortable, livable environments will never change.
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