Today, light-emitting diodes (LEDs) represent a lighting solution offering more light with less energy, little heat production, excellent controllability and a fraction of traditional lighting maintenance needs. However, if you want to harness the full potential of LED lighting and lighting controls, avoid making these mistakes.
1. Misinterpreting the correct way to design with delivered lumens.
“Delivered lumens” refers to the total light coming out of the luminaire, rather than the actual light source. For example, an LED tube may deliver 3,500 lumens per tube. If three of these LED tubes are installed in a luminaire that is 65 percent efficient, together they will produce 10,500 lumens in bare lamp photometry. That figure must then be multiplied by 0.65 (because the luminaire is only 65 percent efficient), equaling 6,825 total delivered lumens.
2. Measuring LEDs in the same way as conventional sources.
While absolute photometry measures delivered lumens regardless of the source, bare lamp photometry fails to consider losses that occur as a function of the luminaire. This means attempting to complete a lumen-to-lumen calculation using bare lamp photometry, without considering the inherent losses, may lead to overdesign. Mistakes here, whether in a retrofit or a new design, can also mean a loss of energy savings. For example, even if only 20 or 30 foot-candles are needed, a bare lamp photometry approach may result in higher than necessary light levels for the task or space.
3. Failing to account for the directional nature of LED tubes.
While fluorescent sources tend to deliver light 360 degrees around the lamp, most LED tubes deliver light closer to 120 degrees. Failing to account for the directional nature of LED lighting could lead to unintended consequences such as uneven distribution or glare.
4. Overlighting, or over-featuring.
Though this is a common issue, it can be avoided by selecting luminaires that are appropriate for the intended application. For example, luminaires with directional or volumetric lighting capabilities (e.g., ambient lighting, night lighting or spotlighting) may not be necessary in a particular room. Instead, the desired effect may be achieved simply by dimming or raising light levels as needed.
5. Ignoring lighting qualities beyond basic efficiency and lamp life performance.
It’s crucial to consider how the space is used to determine necessary characteristics of the lighting in the space. For example, lighting in health care must provide excellent color rendering and a consistent and uniform color of white light throughout the facility, be energy efficient and meet applicable building codes and green building initiatives. Lighting solutions must also offer the desired level of controllability for all occupants, be easy to maintain and provide a cost-effective solution.
6. Not incorporating lighting controls.
Controllability is the most significant advantage of LEDs over linear fluorescent and compact fluorescent (CFL) light sources. For example, the dimming performance of an LED light creates additional opportunities for facilities to generate energy savings above and beyond what is required by building codes, without occupants being aware the lighting system is operating in an energy-saving mode. This is because the low-voltage nature of LEDs gives the dimming curve an almost linear quality.
7. Overcontrolling the light source.
Because LEDs are inherently easy to control, these sources can also be overcontrolled. Even though today’s technology is moving toward feature-rich, total control, this level of control may not always be necessary or be an efficient use of resources. For that reason, facilities may want to incorporate automatic lighting controls, rather than lighting controlled at the user level, in many areas.
8. Not accounting for flicker.
All light sources powered by an alternating current (AC) power supply, including LED fixtures, flicker to some degree. With that said, the visible flicker of LED fixtures can be removed by providing the LED light source with a constant direct current (DC) power supply.
9. Opting for inexpensive or lower-quality LED retrofit bulbs.
All LEDs were not created equal, and the market is still rampant with many lower-quality products, which can create power quality issues. Always ensure that the quality of the LED light source is appropriate for the application.