Halogen Lamps

Twenty five years ago, the halogen light source began outshining its predecessor, the incandescent bulb. Producing 15-20 lm/W and offering a much longer lamp life, halogen was more efficient in both energy and materials. As an added bonus that maximum efficacy is maintained throughout the life of the lamp.

Today, halogen lamps are available for both line voltage and low voltage and a variety of lamp types.  The two most common halogen lamp types are a parabolic aluminized reflector (PAR) and a multi-faceted reflector (MR). The halogen PAR lamp is available only in line voltage. The MR-style low-voltage lamp is available in more wattages (20-75W) and a larger selection of spot or flood beams than the MR halogen designed for line voltage. Both lamp types produce a significant amount of heat while operating.

Compact Fluorescent Lamps

Compact fluorescent lighting (CFL) operates on line voltage (120 V and 277 V) and requires a ballast to help regulate the electrical energy running to the lamp. CFL consumes up to 75 percent less energy than incandescent lights and are able to generate 35-60 lm/w.  The lamps last up to 10 times longer than the incandescent standards, illuminating outdoor areas for almost 10,000 hours per lamp.

Metal Halide Lamps

Metal halide lamps operate on line voltage and offer a longer lamp life and better efficiency than compact fluorescent, halogen, and incandescent lights. This lamp type requires a ballast to provide proper starting and operating voltages, which contributes toward the higher price tag often associated with metal halide fixtures. However, the higher initial cost is balanced by a low cost of ownership. Metal halide lamps will provide more light on a project, more efficiently, and for a longer period of time than the less costly halogen alternative.   

Light Emitting Diodes (LEDs)

LEDs, also referred to as solid state lighting (SSL), are the newest and latest low-voltage light sources used in landscape lighting.  Highly efficient, these sources are able to create 30-100 lumens/Watt.  Beyond improved energy efficiency; the system life is much longer than other available light sources. LEDs are rated to operate for approximately 50,000 hours before needing to be replaced.  This long life significantly reduces the maintenance required by the system and the number of lamps sent to landfills every year.

Although LEDs are highly efficient, they do generate some heat, so it is important that the lighting fixture is capable of heat management. Most importantly, the diodes are very heat sensitive and excessive exposure to heat will seriously diminish or completely fail an LED board.

Low-voltage or Line-voltage Landscape Lighting

The selected light source will determine whether or not the landscape lighting system will be low- voltage or line-voltage.

Line-voltage systems mostly use 120v or 277v supplied by the local power company.  Your average home is supplied with an input voltage of 120 volts operating most household appliances.

Low-voltage lighting systems require a transformer to lower the line voltage. These products often operate with a voltage between 12v and 24v.

While both low-voltage and line voltage systems are excellent matches for exterior lighting, there are a few differences between the systems that are important to highlight.

Energy Efficiency

Line-voltage systems operate with a lot more power than their low-voltage counterparts.  These line-voltage systems accomodate larger lamps with a much higher wattage, creating a significant electrical load with a small number of fixtures. In comparison, low-voltage lamps are physically smaller, available in lower wattages and able to create more light with less energy.

Low-voltage lights produce 2.5 times as much light as line-voltage incandescent lamps.  For example, a 50W low-voltage lamp generates as much light as a 125W incandescent lamp. This improved energy efficiency can create a savings of $7.50 per lamp every 1,000 hours of operation.  This savings is based on an estimated cost of 10 cents per kilowatt-hour (kwh). 

 "In the past, landscape lighting in commercial areas was always line voltage. Now low-voltage lighting has advanced so significantly that a designer can use low-voltage instead of line voltage, provide the same light output in the space and use remarkably less energy," said Gabe Kauffman, a designer and installer at Landscape Lighting Design in Des Moines, Iowa.

 

 "In the past, exterior lighting in commercial areas was always line voltage. Now low-voltage lighting has advanced so significantly that a designer can use low-voltage instead of line voltage, provide the same light output in the space and use remarkably less energy," said Gabe Kauffman, a designer and installer at Landscape Lighting Design in Des Moines, Iowa. Photo courtesy B-K Lighting

 

Ease of Installation

Only a licensed electrical contractor can install line-voltage landscape lighting systems. When installing line voltage, the wire must be properly buried in the ground at least eighteen (18) inches and placed in a protective conduit. The required trenching, materials and expertise make line voltage systems laborious to install and difficult to move, limiting the ability to modify the initial system design to accommodate the landscape as it matures.

In most cases, low-voltage lighting can be installed without an electrical contractor. Fixtures are powered and connected by an above ground cable that is easily camouflaged. No trenching or hardwiring is necessary, although the cable can be buried for cosmetic purposes. Ease of installation translates to easy relocation, allowing low voltage systems to be moved to complement the trees, shrubs, and foliage as they evolve.