Posted under Alpenglow Lighting Design News
At Alpenglow, we tested (in an unscientific manner) several LED A-lamp replacements from big-box retail stores. Although none had the lumen output of the specification-grade versions, they were close (nominal 12W lamps have approximately 800lm). The samples purchased were all labeled as being dimmable and were tested on Vantage Scenepoint dimmers.
A lamp comparison was done in a pair of identical stairwells with identical pendants. One had a 150W halogen lamp, the other a 12.5W/810lm LED lamp. Under the halogen lamp, we read 2.3 footcables, under the LED, we read 1.7fc. So, for an approximately 92% reduction in wattage, we saw a 27% light reduction. For residential use, the .6 fc drop is nearly impossible to perceive, but the reduction is power consumption will certainly affect the monthly power bill.
Of 2 LED lamps tested, the 810lm version (versus a 12W/800lm) had excellent color, good light output, and good dimmability. It should be noted that many existing dimmers are designed for loads of 40W or more, and may flicker with low wattage loads. In the case of the Vantage Scenepoint dimmers tested, they worked fine at 12.5W. However, most LED dimmable lamps will switch off at approximately 10% and will not dim all the way to off. By changing the dimming profile in Vantage’s software, we were able to tune the dimming of the lamp so that it worked fairly well.
Consumer-grade LEDs will typically cost less than specification-grade, and will typically have shorter lifespans (~25,000 hours). However, they can be purchased for $20 or less, and will still last 8-10 years in residential use. Of course, the technology will also progress and brighter, less expensive lamps will appear on the market. Based on the light output, we recommend replacing incandescent lamps with LED versions as they burn out. The savings in energy will offset the installed cost very quickly.