Thinking of buying energy-efficient LED (light emitting diode) fixtures for your home? There are a lot of LED lights on the market today, but buyer beware.

Good, long-lasting LED lights are also available—and will generally cost more. Here are some things you should check out as you shop, courtesy of Philips Color Kinetics.

• Where’s the power supply? Most LEDs require low-voltage, so they must have an AC-to-DC adapter, transformer, or power supply to operate them. These can be internal or external to the fixture.
• Color Temperature, or Correlated Color Temperature (CCT) refers to the appearance of the light. “Warmer” yellowish light like that from an incandescent bulb is in the 2700 to 3000 Kelvin (K) range, while bluish or cool light like that of some fluorescents is in the 5000K-plus range.
• The Color Rendering Index (CRI) is a measure of the ability of a light source to render colors, on a scale of 100—the higher the better. The CRI for many white-light LEDs is between 75 and 85. However, a higher CRI is being questioned as a reliable indicator of light preference among consumers.
• How does the manufacturer define lifetime? How is it measured? Lifetime typically refers to the useful time of light output, also referred to as lumen maintenance. For white LEDs, lifetime refers to the time after which 70 percent or more of the useful light remains. 
• Does the quoted lifetime include the electronics and other components necessary to drive the LED source?
• Does the fixture have any special features for heat sinking or thermal management? Though the light from LEDs itself is not hot, the backs of the fixtures can get very hot. This is a challenge in designing long-lasting and useful LED fixtures.
• What warranty is offered? Beware of vague guarantees.
• If multiple white-light LEDs are used, are the color points among them adequately matched? LEDs can vary, due to variations in the fabrication process. You should look for fixtures that have consistent color performance from LED to LED.
• Does installation of LED fixtures include all the necessary components to operate the lights? Many LED fixtures require external components and controls in order to be operated.

About the Author:
Steven Castle - Contributing Writer

Steven Castle is a writer, editor, and humorist who recently completed Filthy Rich Things, a savage satire on our thirst for success and wealth. He is presently expanding his magazine work by writing more about alternative energy sources and green building.