Increasing Energy Efficiency With Low-Voltage Lighting

By Perry Romano, IESNA, LC

Landscape lighting provides useful and functional light, along with enhanced home value with nighttime ?EUR??,,????'??curb appeal.?EUR??,,????'??

In the drive for greater economy in commercial and residential lighting specifications, today?EUR??,,????'???s landscape lighting fixtures are available with many different energy-efficient lamp choices. (i.e. ceramic metal halide; compact fluorescent; LEDs; halogen.)

Of the myriad landscape fixture and lamp choices available to contractors, specification-grade low-voltage lighting, while not new, is garnering renewed attention as one of the most cost efficient, flexible and readily available, for use indoors and out.

 

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Halogen Lighting

Halogen lamping provides an ideal light source for low-voltage landscape lighting. They are available in many color temperature ranges, economical wattages and lamp styles; are inexpensive and readily available when replacements are needed; and have a 5,000 hour lamp life.

Smaller, often sleeker, 12-volt fixtures allow them to be easily concealed or to be less invasive to a landscape design. Very often, there is no need for conduit below grade, on buildings or trees, and no junction boxes. Stake-mounted landscape fixtures can move as needed and adjust for plant growth.

As trees mature and plantings are reconfigured over time, low-voltage landscape lighting is inherently flexible; creating minimal disruption to grounds when fixture locations are changed to accommodate a new site plan.

As trees mature and plantings are reconfigured over time, low-voltage landscape lighting is inherently flexible; creating minimal disruption to grounds when fixture locations are changed to accommodate a new site plan. Low-voltage lighting is readily available for wet, even submersible, use. It is safe around a property for pedestrian traffic.

If contractors are inexperienced with low-voltage technical constraints inherent to the design and installation of such systems, problems will occur and hinder performance.

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Voltage drop is the most important thing to understand when installing low-voltage landscape lighting. Without proper voltage, lamps can project a yellow cast and be dimmer (under voltage); or be too bright (over voltage), with ?EUR??,,????'??hot spots?EUR??,,????'?? projected on building or landscape features. Either condition can shorten lamp life, cause premature failure and unanticipated lamp replacement.

New developments have made it is possible for landscape contractors to use miniaturized voltage regulators at each fixture, converting fluctuating voltages as high as 24-volts down to an even 11.6 volts. Such voltage regulators are installed in-line on each fixture, either by the manufacturer, at a contractor?EUR??,,????'???s job staging area, or right at the project location.

Make certain to ensure that the each fixture is receiving between 10.8 and 12.0 volts. Ideally, each fixture should receive the same level of voltage.

Voltage Limits

It is recommended that low-voltage landscape fixtures be set to receive a steady 11.6 volts, when installing a 12-volt system.

Given these and other advantages of low-voltage landscape lighting, especially its inherent operating economy over time, it is the clear winner in conserving energy for a client, while preserving the integrity of a landscape contractor?EUR??,,????'???s hard work.

This scallop-shaped path light has style that works in the day too. However, beware of mixing too many styles on a single site.

Illuminating Info

1,000: Hours, the expected life of bulbs used in landscape lighting.
Source: www.lightingfacts.com

35: Watts, the maximum size of low-pressure sodium area lighting recommended where a dark sky experience is desired but area lighting is needed. The monochromatic LPS light used at low levels will preserve dark adaptation more then any light source other then red lighting.
Source: www.darksky.org