Author: Robert Schindler, P.E., Process Plus Electrical Engineer &
Best Practice Lead
November 25, 2013
…that is the question. In recent years the advent of LED light sources for general illumination, as well as specialty lighting, has both complicated and simplified one’s choices when it comes to selecting luminaires (I will use the term ‘luminaire’ in place of ‘light fixture’.)
The need to purchase lighting typically happens for two reasons: new construction or renovation/retrofit. Each one has slightly different criteria for selecting fixtures. In Part I of this article, we will review a few basic bits of information along with the first of two reasons, new construction. Part II will focus on renovation and retrofit projects.
For many applications, the cost of LED luminaires has decreased in price to be at parity with similar fluorescent or HID luminaires. The breadth of offerings from the manufacturers has also touched virtually every possible lighting application. This should not be construed to mean that there is a LED replacement for every conventional fluorescent or HID luminaire, but there is usually a reasonable substitution.
The main reason that LED luminaires have decreased in price is that the LEDs themselves are more widely available; therefore more manufacturers have access to an adequate supply. The technology of LED drivers (analogous to fluorescent ballasts) has made it possible to tune LED performance more closely to the fixture designs. The drivers are also now manufactured to be used in common existing lighting control systems (0-10V dimming systems, daylight harvesting, etc.). The range of colors now available in LEDs also allows manufacturers to replicate the lighting color temperature of fluorescent and incandescent lamps that we are all accustomed to (it used to be that LED light was always stark white; a wide selection of ‘warmer’ colors is now available).
Now let’s look at the situation of new construction. In general, if a particular lighting application can be fulfilled with either a standard luminaire or a LED version; serious consideration should be given to using the LED from the start. LED luminaires will use less energy than their similar counterparts and the light sources generally have longer life. Therefore, the operational costs going forward will be less. If the luminaire cost difference is small for the LED unit, the payback is quick. Savings can also be realized in the electrical distribution system since less lighting power load can reduce the amount of copper that has to be installed. Finally, the latest energy codes that apply to new construction are pushing the lighting power density down. LED luminaires make energy code compliance much easier to achieve while maintaining quality lighting. (For those unfamiliar with the term, ‘lighting power density’, it is the amount of electric power used to illuminate a space, quantified as watts per square foot).