Tools for Comparison
For PAR lamps used in accent lighting applications, the principal metric used to measure output is often not lumens but center-beam candlepower (CBCP), a gauge of maximum luminous intensity, expressed in candela, at the center of the beam. A related unit of measurement is beam angle—the angle at which the luminous intensity measures half of CBCP. Beam angle determines whether the given lamp has a narrow, medium, or wide distribution. Among PAR lamps, typical beam spreads—the distance from one beam angle to the beam angle on the other side of the lamp—include narrow spot (9 to 10 degrees), narrow flood (25 to 30 degrees), and wide flood (40 degrees). Some lamps are available with a very wide flood (45 degrees-plus) emission. A PAR spot and a PAR flood may have the same light, but the spot will have a much higher center-beam candlepower luminous intensity.
Additional metrics, if available, include field angle and spill. Field angle, or cutoff angle, is the angle at which intensity measures 10 percent of total CBCP, and spill represents where emission outside the field angle fades to zero percent of CBCP. These tell us how well the lamp controls the beam pattern. Two lamps, for example, might have similar CBCP and beam angles, but the first lamp may have a smaller field angle and close spill, which means it offers a tighter beam (a harder edge) than the second lamp. Suppose a designer needs to light an object in front of a color backdrop. If the goal is to light the object only, he or she may choose the first lamp; if the goal is to light both the object and some of its surroundings, he or she may choose the second.
In addition to luminous intensity, beam spread, and optical control, other criteria to consider when selecting a directional lamp include color output and rendering, lumen maintenance, modeling, ease of dimming, energy and maintenance costs, and initial cost.
Directional lighting is typically used to produce a higher light level on a task or focal point. For directional lighting in many retail and similar applications, halogen is frequently preferred for its excellent color quality, good modeling, and tight beam control. This light source is packaged with a reflector in a configuration suitable for aiming in a desired direction and pattern for accent, track, landscape, and downlighting.
Regulation coming in July will put millions of directional lamp sockets for halogen sources up for grabs. Energy standards covering incandescent reflector lamps, first instituted by the Department of Energy (DOE) in 2009, and going into effect starting in July, will eliminate a majority of the least-efficient and lowest-cost options from the market in favor of higher-efficacy alternatives. The compliant alternatives include today’s most efficient infrared-reflecting (IR) halogen reflector lamps, as well as LED, ceramic metal halide (CMH), and compact fluorescent (CFL) directional lamps.
The Regulations
The Energy Policy Act of 1992 imposed energy standards on a range of reflector lamps. Fifteen years later, the Energy Independence and Security Act of 2007 strengthened these standards and covered a broader range of lamps, including R, PAR, BPAR, BR (BR30 and BR40), and ER (ER30 and ER40) lamps. Several popular lamps were eliminated, including the 50W and 75W R20, 85W BR30, and 120W BR40.
Two years later, in 2009, the DOE announced new energy standards that will become effective on July 14, 2012, and will cover 40W to 205W lamps with a 21/2 inch-wide reflector; R20 and PAR20 lamps; and 21/2 wide-reflector PAR30, PAR38, BR30 and ER30, and BR40 and ER40 lamps (120V or 130V, standard or modified color output). Lamps that do not comply cannot be manufactured in, nor imported into the United States after the July deadline.
Exceptions, which are expected by many manufacturers to remain in effect until at least Dec. 31, 2014, include 45W or smaller wattages of R20; 50W or smaller wattages of ER30, BR30, BR40, and ER40; and 65W BR30, BR40, and ER40 lamps. These lamps (particularly the 65W BR30 and BR40 lamps) are popular in residential accent and downlight applications. Additional exceptions, which are expected to remain beyond Dec. 31, 2014, include colored lamps, rough- and vibration-service lamps, and other specialty lamps.
To make a long story short, today’s standard incandescent reflector lamps are on their way out. This will vacate millions of sockets that will have to be filled with more-efficient sources.
The New Baseline
As with similar regulations, a technology is not specifically being banned, but it is being asked to step up in terms of efficiency. A small group of halogen PAR lamps already complies with the new regulations. Due to similar performance and a typically lower cost than other alternatives, such as CMH and LED, these lamps are expected to form the new baseline in this category for halogen-preferred applications. A selection of compliant 120V PAR30 and PAR38 lamps is offered by the major lamp manufacturers under the respective proprietary designations HIR (GE), IRC (Philips), and IR (Osram Sylvania). (See the online version of this article for a chart listing these lamps and their respective data.) PAR lamps tend to be used in applications requiring tight beam control, such as accent and tracklighting, while R lamps are used for applications that require a broader spread of light, such as downlights and landscape lighting.
These halogen lamps have a metallic IR coating on the light-emitting capsule, which allows visible light to pass through while reflecting, or recycling, infrared output back to the filament. Although line-voltage halogen lamps are generally hot, this recycling improves the efficiency of the halogen cycle by enabling the lamp to achieve its required temperature using less energy, and it can be used in the lamp’s design to increase efficiency, to extend service life, or both. The most efficient IR halogen lamps that pass the DOE regulations produce similar light output as a standard halogen lamp and use as much as 20 to 30 percent less energy. For example, a 120V 55W IR PAR30 lamp can replace a 75W halogen PAR30, creating a 26 percent energy savings.
Otherwise, these lamps operate similarly to standard halogen, with a CRI rating of 98 to 100, tight beam control, good modeling, and lumen maintenance of more than 80 percent at end of life for most. Lamp life is rated from 3,000 to 4,200 hours. The primary trade-off is higher initial cost.
Compact Fluorescent
The potential for CFLs is limited, when it comes to narrower beam spreads and increased beam control. Because of their size and their distribution as a linear source, coupled with flatter modeling and difficulty in dimming, CFLs are better suited to applications requiring very wide flood distribution, and where modeling, dimming, and color quality are less important.
Self-ballasted integral CFL reflector lamps are available in 9W to 14W R20; 23W R25; 15W R30; and 26W R40 configurations—in addition to 15W to 16W BR30; 19W to 23W BR40; and 23W to 26W PAR38 floods. Typically, these lamps offer 60 to 70 percent energy savings over halogen lamps. A 14W CFL R20, for example, might replace a 50W halogen R20 for 70 percent energy savings.