By Cruz R. Pérez
Homeowners’ love of outdoor living shows no signs of slowing, according to the American Society of Landscape Architects (ASLA). Their 2012 Residential Landscape Architecture Trends survey ranked landscape and outdoor lighting as one of the top five trends for outdoor living features.
In addition to being aesthetically pleasing, professional landscape lighting serves further purposes. It provides home security, allows for safe passage throughout a property, and enables homeowners to extend their amount of time spent outdoors.
Prior to beginning a landscape installation, it is important to consider voltage and lamp type during the design process.
Low-voltage landscape lighting
Safety should be top of mind for lighting professionals. Underwriters Laboratories recommends the maximum safe voltage to which individuals are subjected to not exceed 15 volts. Ideal for landscape lighting, 12-volt systems are less expensive to operate than 120-volt systems and have lower wattage lamps available that do not require a conduit.
The wide variety of lamps and fixtures available in 12 volts allows the amount, intensity and pattern of light to be controlled as desired. Being small in size, the fixtures are less obtrusive than 120-volt systems, and considering the lower voltage involved, a 12-volt lamp filament can be wound much more closely together than a 120-volt filament. This creates a small point from which light is produced, which is characterized by focused sharp shadow lines when mounted inside a clear bulb. In addition, the color balance in 12-volt light is truer to the color of sunlight than most 120-volt lamps.
After selecting a voltage system, the second step is to consider the lamp type that will best complement the project.
Add light, not energy
Since 2002, average electricity rates in the U.S. have risen by more than 25 percent, and the demand for eco- and budget-friendly solutions has been on the rise. Experts predict that high-efficiency light-emitting diodes (LEDs) will rapidly replace traditional incandescent sources, providing equal light output while using 80-90 percent less energy.
An LED is a semiconductor that converts electricity into light. It is a solid-state device that does not contain a breakable filament. Each LED diode is small — typically one-quarter inch or less in diameter — and multiple LEDs are arrayed in patterns to create the desired amount of light output. These systems are naturally best at providing light in a focused direction, so advanced optics are often combined with the LED arrays to create carefully controlled, glare-free lighting patterns. Unlike a halogen lamp that generates significant heat together with light output, LEDs themselves do not generate any infrared heat. This allows the fixture lens to remain entirely cool to the touch, which is a significant advantage for in-ground and accent fixtures.
LEDs require a driver to operate. The driver converts incoming AC power to DC current and regulates the voltage for optimum operation. The quality and efficiency of the driver is essential to determining the longevity and performance of the fixture. Low-quality circuits will lead to premature fixture failure. Effectively integrating the driver into a fixture is a complex engineering task. The driver is essentially a circuit board, so it must be hermetically sealed to protect its components from moisture. In addition, excess heat created by the driver board can dramatically reduce the light output and the fixture longevity; therefore, the fixture must be designed to dissipate heat effectively.
Manufacturers of LEDs use a measure called color temperature to numerically indicate the appearance of the color of light sources. Those with a color temperature of 2900K have a warm, orange-white appearance. This would include most incandescent and halogen light sources. LEDs are now indistinguishable from their halogen equivalents in color and lumen output — resulting in the dramatically increased acceptance of LED technology in residential applications.
Homeowner benefits of using LEDs
LEDs offer a variety of benefits for homeowners. Whereas incandescent lamps use up to 90 percent of energy consumed as heat and only 10 percent for actual light, LEDs are the opposite. They use up to 90 percent of the energy consumed as light and lose only 10 percent to wasted heat.
Considering an installation using 900 watts of halogen lighting and operated nightly for 10 hours with a local rate of $0.145 per kWh, the annual energy cost is approximately $476. The same system with an equivalent number of LED fixtures and lumen output costs approximately $95 per year to operate. LEDs have a rated life based upon the time it takes for the light output to decrease to 70 percent of the original output, which is typically about 50,000 hours or 17 years of normal residential use. A typical incandescent fixture will need to be re-lamped 10 or more times during the life span of a typical LED fixture.
Benefits for landscape professionals
Professionals can use MR-16 LED lamps to upgrade existing landscape lighting installations to the energy-saving benefits of LED. Because these lamps use far less wattage than comparable halogen lamps, they save dramatic amounts of energy while also allowing for the installation of more lamps per cable and transformer. This also makes it easy to add new fixtures when converting existing lamps to MR-16 LED.
Dramatically lower wattage consumption by each LED fixture allows landscape lighting professionals to significantly increase the number of fixtures on each cable run and correspondingly decrease the size of the system’s transformer. For many residential installations, a single continuous cable run can be all that is required to supply power to more than two dozen fixtures. Because each fixture contains a driver that helps regulate and balance the flow of current, all fixtures will have uniform light output regardless of minor variations in incoming voltage.
The combination of lower power use and self-balancing fixtures can virtually eliminate the need for laborious voltage drop calculations in many systems. It can also allow for the addition of more fixtures into many installations without affecting the performance of the system’s balance.
Future of LEDs in landscape lighting
In the past decade, landscape lighting has been one of the most profitable segments of the green industry. Once used solely as indicator lights for electronics, LEDs have evolved into a major lighting technology, and the LED lighting business is growing rapidly. According to the U.S. Department of Energy, no other lighting technology offers the same potential as LEDs to save energy and to enhance lighting quality and reliability. With an ideal mix of efficiency and output, LEDs are changing the way that professionals light outdoor living spaces.
Cruz R. Pérez serves as vice president of sales and marketing at Vista Professional Outdoor Lighting, where he is responsible for the development of new products, focusing on energy-efficient solutions, incorporating LED low-wattage HID and compact fluorescent light sources. Actively involved in the landscape and architectural lighting industry for more than 16 years, Pérez holds Bachelor of Arts and Juris Doctor degrees from California State University and Pepperdine School of Law, respectively.
To learn more about landscape lighting and current LED products available from Vista Professional Outdoor Lighting, visit www.vistapro.com.