A matter of esthetics
In addition to these practical benefits, LED fixtures also offer certain esthetic advantages. For example, the ‘white’ light one gets from an incandescent fixture has a yellow or green tinge to it; in contrast, a white LED fixture has a cool blue tint. The human eye is more sensitive to blue at night, so LED whites tend to appear brighter, crisper and cleaner.
Further, LEDs offer a broader, brighter and richer colour palette because they use the additive properties of light (as opposed to filtering out, or subtracting, colour from white). Thus, all the energy is going to generating the desired colour. With technologies that start with white and subtract, some energy is wasted.
There are two ways to make LED fixtures cast different colours. One is to control how many diodes of each main colour—red, green and blue (RGB)––are on at any one time. For example, to create a purple light, all the green diodes may be turned off, allowing the red and blue to combine. To switch to a pure green tint, the reds and blues would be turned off, while all the greens would come on. Using this approach, any colour combination is possible.
The other approach to colour mixing is achieved by varying the current to each of the RGB colour arrays. This is most often achieved by pulse with modulation (PWM). The controller for PWM colour mixing may be an external unit or part of the lighting unit itself.
In recent years, some LED pool and spa lights have been designed with special lens geometry and reflector design that delivers brighter, more uniform light distribution than earlier products. Some newer products also have special lenses that can be rotated up to 180 degrees, providing a wide or narrow beam pattern. This added design flexibility is also contributing to the growing adoption rate of LED technology for pools.
Keeping up with design
Swimming pools have become more complex in recent years. Anyone who is building a new swimming pool today is probably investing a lot more than was typical 10 or 20 years ago. During the pool building boom of the 1980s, the average pool may have been a $30,000 or $40,000 project. Before the economy slowed down, the average pool price was much higher, arguably double. While fewer pools are being built today, the people building them (or upgrading existing pools) tend to want the most technologically advanced and energy-efficient options.
Poolscape design trends are also well suited to LED technology. Roughly 15 or 20 years ago, most pool surfaces were smooth and white, reflecting light very well. As such, they used less energy to achieve proper illumination. As darker pool surface colours and textures—which absorb light, rather than reflect it—started becoming more popular, designers began looking for different lighting options.
Depth also affects brightness. If you illuminate a pool’s deep end and its shallow end with the same amount of light, the shallow end will glow brighter. You see the same effect from sunlight as you fly over natural bodies of water. Having a lighting system with nearly infinite adjustment possibilities—which can be achieved with the right combination of LED and digital communication technology—increases the pool owner’s degree of satisfaction with the finished project.
A final word
As pool and spa builders, owners and operators seek out more ‘green’ alternatives, and look for ways to save money on increasingly complex installations, LED lighting offers a wealth of possible advantages. As manufacturers continue to offer more options and flexibility, the switch to LEDs will be easier for those looking to add a little light to their pool, spa or water feature.
David MacCallum is the senior global product manager of lights and automation at Pentair Water Pool and Spa in Sanford, N.C. He can be reached via e-mail at david.maccallum@pentair.com.
