By Kathryn A. Navarra
The key to becoming a successful landscape lighting company is understanding the role lamp selection plays in the final outcome of a design and installation. “Landscape lighting designers are like artists who use all types of mediums to produce artwork, our medium is light and the way we paint light is based on lamp selection,” said Michele Swetesich, executive director of the Association of Outdoor Lighting Professionals.
Recognizing what types of lamps are available will allow you make the best selection for each specific site. “Like with almost anything you buy, you can get a poorly designed and produced light bulb as well as a good one,” said Jeffrey Dross, senior product manager with Kichler Lighting. “The real key to a successful job is a well-engineered, good quality light bulb.”
The most widely recognized lamp is the PAR-36, which stands for parabolic aluminized reflector. The lamp is easily recognized because it looks like an old tractor headlight. PAR-36 lamps can be incandescent or halogen. Incandescent lamps are typically not used due to comparatively short lifespan of 2,000 hours and the warmer, yellow coloration it produces. Halogen PAR-36 lamps are rated for up to 4,000 hours (depending on quality) and emit a softer, cooler colored light. Screw terminals on the back of the lamp are used to attach the lamp to the terminals on the fixture.
The lamp includes a glass reflector to control the direction and beam size. Designed to bounce light off of the reflector and out to the front of the lamp, the PAR-36 is often used to create a less defined pool of light. “Personally I like the PAR-36 when looking for a spill of light,” said Dross. “On a statue I have at home, I cross lit it with two PAR-36 fixtures to put a pool of light over the artwork, and for this particular piece it worked well.” Traditionally, PAR-36 lamps are used with in-ground fixtures because they are sealed. The drawback to using the PAR-36 lamp is the short lifespan in comparison with other lamps. Even well-made PAR-36 lamps have significantly shorter life spans than other lamps.
The mirrored reflector (MR-16) lamp is the most commonly used lamp, especially in accent lights and directional lighting situations. A halogen filament in the center of the lamp is surrounded by a mirrored reflector that directs the pattern of light as it bounces off the back of the lamp. The halogen filament provides a whiter, more intense light than an incandescent lamp of the same wattage. Available in two styles — an open front or a closed glass front — these lamps are called bi-pin because of the two prongs used to attach the lamp to the socket inside the fixture. Swetesich suggests always using a glass cover because the MR-16 lamp is more fragile than the PAR-36 (the glass reflectors of the MR-16 can be easily damaged by grease and dirt from the installer’s fingertips). The technology of a MR-16 allows for lamps with lives of 10,000-20,000 hours, as well as a variety of wattages and beam spreads. Although lamp life can be as high as 20,000 hours, Dross points out that the average is probably closer to 2,000 to 5,000 hours because less-expensive, lower-quality lamps are typically being installed.
When purchasing an MR-16, careful selection will lead to a better final product. “Look at premium-quality manufactures,” said Dross. “You will pay more money for these bulbs, but if the back surface is not well engineered you are likely to get dark spots, hot spots or irregular beam patterns on the surface you are trying to illuminate.”
Other lighting options
A cousin of the MR-16 is the Quartz Halogen Bi-Pin. This lamp is actually the inside of an MR-16. However, the reflective glass that gives the MR-16 its directionality is not included on the Quartz Halogen Bi-Pin. Typically, it can be found in path lights due to the size of the fixture and the lamp. Most path lights are smaller in design and, therefore, require a much smaller lamp. Depending on the wattage for which the fixture is rated, the Halogen Bi-Pin is available from five to 100 watts in increments of five.
Recent additions to the market include the MR-11 and MR-8. These lamps are much smaller in comparison to the PAR 36 or MR-16. An MR-16 contains a 2-inch reflector, while an MR-11 holds a 1.36-inch reflector and the MR-8 measures 1 inch. The smaller lamps allow for less-obvious fixtures that can easily be concealed in the surrounding landscape.
An alternative to the MR-16 or Par-36 is the Xenon lamp, which looks similar to an MR-16, but can be used in applications where the MR-16 cannot. Xenon gas is used inside the filament to produce the light output. Although Xenon lamps are limited in wattage (five, 10, 15 and 20 watts) and beam spread, they are rated to have longer lamp life than an MR-16 and can be handled with bare hands. “Xenon lamps generate a lot less heat than the MR-16,” said Swetesich. “Not all fixtures can handle high temperatures, and the Xenon is a good alternative.”
Incandescent bayonet and wedge-based lamps are available, and can sometimes be found in path lights because of their compact size. It is helpful to know what the lamps look like in case you are maintaining a system you did not install. However, these lamps are not commonly used on new installs because of shortened life and yellow coloration.
Advanced lamp options are available as lighting designers become more highly skilled. Pop-Star lamps use a dichromatic lens to create colored (red, blue, purple, etc.) effect without degrading the light output the way a secondary lens can. “As you experience new technology, a light bulb goes off in your head and you see different ways to design, install and understand how to use a full palette of lighting available,” said Dross.
The ultimate goal of a landscape lighting designer is to create an impact with the lighting design you create. Swetesich and Dross agreed the best method to learning what each wattage and beam spread looks like is to experiment on your own property. “By understanding the difference in a 10-degree and 50-degree spread, and which trees require specific wattages due to height, you will be like an artist working with a full palette,” Dross noted. “Figure out your vision for the end result and use the appropriate tools to obtain it.”
Ultimately, using the proper lamp is the key to obtaining the desired impact. It will cost a bit more, but will be well worth it when the installation is complete.
Kathryn A. Navarra is a landscape industry professional based in New York. She is also an accomplished author and freelance correspondent with more than 200 published articles to her credit. She can be reached via e-mail at firstname.lastname@example.org