Lighting Research Center NYSERDA Lighting Patterns for Homes Image Map


Incandescent Reflector

Incandescent reflector bulbs contain a reflective coating and therefore provide directional light. The shape of the light beam is cone-like and can be specified in a range of beam spreads from narrow spot to wide flood. A spot bulb will have a narrower distribution with greater intensity at the center of the beam than a flood bulb with the same wattage and bulb shape. When selecting reflector bulbs, compare the center beam candle power (CBCP), which indicates the intensity a the center of the beam.

Incandescent bulbs offer significantly lower efficacy (the amount of light produced divided by input power) and shorter life than fluorescent and LED bulbs. Restrict their use to applications where short hours of use are expected, or where there are no other alternatives.

Reflector bulbs come in a variety of shapes and sizes. The letter designation refers to the shape, and the number indicates the maximum diameter of the bulb in eighths of an inch. For example, a bulb labeled "PAR-30" is a parabolic aluminized reflector (PAR) bulb 3 3/4" in diameter at the widest point. Because reflector bulbs vary in size, check to be sure the bulb fits in the fixture housing. Reflector bulbs fit into the same medium-based sockets as common incandescent bulbs.

BR bulbs are molded from "soft" soda lime glass and should not be used outdoors without an enclosure. It is best to use BR bulbs in deep, well-shielded indoor fixtures.

Incandescent PAR bulbs, molded from sturdy parabolic aluminized reflector glass, are used extensively for residential outdoor area lighting. Most PAR bulbs are halogen, which extends bulb life. Halogen infrared (IR) bulbs have a reflective coating to redirect infrared energy back onto the filament to save energy.

The light from BR bulbs is softer than that from PAR bulbs, which produce a more focused beam.


  • Incandescent bulbs become very hot. Keep combustible materials away from the bulb and avoid touching while in use.
  • PAR bulbs come in a variety of beam spreads, from very narrow spot to flood. The bulbs appear alike when turned off. Refer to the beam spread and CBCP to select a bulb with the intended effect.
  • Halogen bulbs can be dimmed, but occasionally they should be operated at full light output to retain the long life benefits.


Example Patterns