How do LED and Metal Halide Fixtures compare once installed?*
Energy efficiency is an important consideration in the parking structure management.
During the construction of a new facility in 2009, TimHaahs compared the lighting quality of an actual installation of LED and metal halide lighting. The lighting manufacturer commissioned a point-by-point lighting analysis to determine the number of LED fixtures required to replace the 175-watt metal halide fixtures. The lighting engineer for the LED fixtures determined that each metal halide fixture could be replaced by 1.5 50-watt LED fixtures. The photo below illustrates the results.
The LED fixtures appear in the foreground and the metal halide fixtures in the background. The team noted a spotty “checkerboard” pattern on the floor from the LEDs and the lack of illumination on the side walls. Compare the foreground lighting to the metal halide fixtures in the background; the metal halide fixtures have significant lateral and up-light throw, illuminating the walls and the ceiling. We found, in this case, that the metal halide fixtures resulted in the feeling of a more open and uniformly lit space.
While these two lighting configurations were comparable on paper, the reality was significantly different than the analysis. LED illumination at the floor surface was 8 footcandles directly under the fixtures while the metal halide fixtures illuminated to a level of 18 footcandles at floor level at the midpoint between two fixtures.
* Federal, State, and Local codes govern most of these requirements and should be thoroughly investigated. Data presented herein should be considered guidelines only. For more specific information, please contact TimHaahs via email at info@TimHaahs.com