Comparing Line Voltage and Low Voltage
This month, Randall tackles a cost/efficiency comparison between line voltage and low voltage light sources.
 
Low voltage recessed adjustable fixtures, using 12V halogen lamps, provide 100W of dazzle for 50W worth of power.
Randall, in the middle of a family room remodel, my customer’s architect recommended low voltage recessed lights (MR16). But the less expensive alternative is line voltage 4-inch recessed lights. Can you provide a cost/energy-efficiency comparison between low voltage and line voltage?
I often hear people saying that an MR16 bulb uses less electricity than a 120V reflector bulb. In truth, a 50W MR16 bulb uses as much power as a standard 50W reflector bulb. The difference is that it gives you close to 100W worth of illumination for 50W worth of power consumption. But there is also the issue of lamp life: low voltage bulbs compared to line voltage bulbs. A standard household bulb lasts 750 hours, while a standard reflector bulb lasts 2,000 hours, and a standard MR16 lasts 6,000 hours. Note that this is what is called average rated lamp life, which essentially means that at the rated life, such as 750 hours for a household bulb, half of the lamps would be burned out at the 750-hour mark and half would last longer than 750 hours.
Randall Whitehead lighting designer
Randall Whitehead, IALD

Randall Whitehead, IALD, is a professional lighting designer and author. His books include "Residential Lighting, A Practical Guide." Whitehead has worked on projects worldwide, appeared on the Discovery Channel, HGTV and CNN, and he is regular guest on Martha Stewart Living Radio. Visit his website www.randallwhitehead.com for more information on books, upcoming seminars and the latest lighting trends.

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