MORE THAN 360 MILLION troffers provide general lighting in commercial buildings, according to the DOE. While fluorescent remains the most predominant light source, the development of LED lighting has cre- ated a major retrofit opportunity. Tubular LED replacement lamps (TLEDs) offer direct replacement of fluorescent lamps in existing lumi- naires. The lamp incorporates LEDs, optics, and heat sinking into a single ready-to-install unit. The majority are bipin-based T8s designed to replace 2´, 4´, and U-bend T8 and T12 lamps. Some products are also available to replace T5 and T5HO lamps. The DesignLights Consortium (DLC) maintains the Qualified Prod- ucts List (QPL), identifying TLED products that satisfy performance cri- teria updated in 2016. DLC requires a minimum efficacy of at least 110lm/W as a bare lamp and at least 100lm/W as tested in a typical luminaire. (In
TROFFERS: REPLACE
OR RETROFIT?
A guide to choosing the right solution for a given application. by Craig DiLouie
comparison, a bare fluorescent lamp has an efficacy of about 100lm/W.) Many utilities rely on the QPL to qualify eligibility for their rebate programs.
Retrofit or Replace? LED troffers and panels offer a fresh alternative to retrofitting existing luminaires. Among the more than 7,300 LED troffer/grid ceiling lumi- naires listed in the DOE Lighting Facts database in December 2016, the majority produced comparable light output to their fluorescent counterparts but at a higher efficacy. In fact, about one out of 10 listed products operated at an efficacy of 125lm/W, identifying the product as DLC Premium. That efficacy is generally lower than TLED bare lamps but at the high end of TLED efficacy when accounting for TLED light losses when operating within a luminaire. It translates to up to 70%
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