Interior Lighting - Buyers Guide
Indoor Lighting: Buyer’s Guide
Learn more about energy-efficient lighting and get tips on choosing the right bulbs and fixtures for your home
Look for the Logo: ENERGY STAR®
Bulb Basics: CFLs and LEDs
Using new technologies can save you 50% - 75% off your lighting energy.1 LEDs are great replacements for halogens in recessed fixtures in kitchens and living rooms. CFLs cost $5 to $10 for a pack of four while LEDs are $10 to $40 per bulb; however, LEDs can last 5 times longer than CFLs.2,3 Both are available for dimmer-controlled indoor and outdoor lighting fixtures as well as table lamps.
Efficacy measures how much light a source emits (in lumens) per electric energy it consumes (in watts). The higher the efficacy, the more efficient the bulb. A typical incandescent has an efficacy of 10 to 17 lumens per watt, while CFLs and LEDs have 27 to 92 lumens per watt.4 While the CFL efficacy may improve in the future, researchers are working to create LEDs with the potential to produce 160 lumens per watt.5
Lumens: How Much Light Am I Getting?
Many CFL labels show a “wattage equivalent” compared to incandescents, but these numbers can be confusing. The real measure of light output is lumens. A 100-watt incandescent bulb produces 1,600 to 1,800 lumens, while a 60-watt incandescent bulb produces about 800 lumens.6 Because CFLs and LEDs are more efficient, they produce the same number of lumens as lower-wattage bulbs.
Tip: an incandescent fixture may block a noticeable amount of lumens coming out of a CFL, reducing its light output.7 It is recommended that you use CFL-specific fixtures to get the most from your energy-efficient bulbs.
Warm or Cool Light? Understanding Temperature
When a light is on, the color appearance of the bulb is called the color temperature, which is measured in degrees Kelvin (K).
Warmer color temperatures (yellow-red colors) range from 2,700 K to 3,000 K. Cooler colors (blue-green colors) have higher color temperatures from 3,600 K to 5,500 K.8 Fluorescents also produce cooler whites with lots of blues, that may be better for visual tasks because they create more contrast. Warmer lights may be better for living spaces because it is more complimentary to skin tones and clothing.
The human eye is more sensitive to blue light and so higher color temperatures help us see details more sharply. Use higher color temperature—“cool white” lights—in garages, sheds, kitchens, and studies. Use lower color temperature—“warm white” bulbs—in living rooms, bedrooms, dining rooms, and bathrooms.
Life Expectancy: Bulbs
Bulb life is not usually shown on lighting packaging, but it’s an important factor to consider when choosing lighting options. The longer the bulb life, the fewer replacement bulbs you’ll need over a period of time. Incandescent lights have lives of 750 to 2,500 hours, while CFLs have lives of about 10,000 hours. LEDs have the longest lives—typically 25,000 – 50,000 hours.9
Content in part adapted with permission from Rocky Mountain Institute’s Energy Briefs.
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1U.S. Department of Energy, Office of Energy Efficiency and Renewable Energy. (2009). Energy Savers Booklet: Tips on Saving Energy and Money at Home. Washington, D.C.: U.S. Department of Energy. Retrieved October 7, 2012, from www1.eere.energy.gov (p. 20).
2The Home Depot. (2012). LED Light Bulbs Product Search. Retrieved October 4, 2012, from www.homedepot.com
3The Home Depot. (2011). LED Light Bulbs Buying Guide. Retrieved October 4, 2012, from www.homedepot.com
4U.S. Department of Energy, Office of Energy Efficiency and Renewable Energy. (2012). Energy Saver: Types of Lighting. Retrieved September 27, 2012, from www.energy.gov
5U.S. Department of Energy, Office of Energy Efficiency and Renewable Energy. (2009). Energy Efficiency of White LEDs. Retrieved October 8, 2012, from www.apps1.eere.energy.gov (p. 1).
6ENERGY STAR®. Learn About Light Output. Retrieved September 27, 2012, from www.energystar.gov
7Goorskey, Sarah, Wang, K., Smith, A. (2004). Home Energy Briefs: #2 Lighting. Snowmass: Rocky Mountain Institute. Retrieved September 27, 2012, from www.rmi.org (p. 3).
8U.S. Department of Energy. (2012). Energy Saver: Lighting Principles and Terms: Light Quality: Color Temperature. Retrieved October 8, 2012, from www.energy.gov
9U.S. Department of Energy. (2012). Energy Saver: Types of Lighting. Retrieved October 8, 2012, from www.energy.gov
This program is funded by California utility customers and administered by Southern California Edison under the auspices of the California Public Utilities Commission.