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LED Pilot Results: Mt. Vernon Road Hy-Vee

Exterior Light FixtureIn October 2010, new LED lamps were installed in the parking lot and Health Market section at the Mt. Vernon Road Hy-Vee store in Cedar Rapids, Iowa.

Members of the Iowa Energy Center performed pre- and post-installation measurements comparing the foot candles produced by the pre-existing lights and the new LED technology.  (A foot candle is a unit of illuminance or light intensity).

In addition to the light measurements, the Iowa Energy Center installed a power monitor that captures energy usage (kilowatt kW) for the parking lot lights on a five-minute interval basis.  According to the final LED Lighting Case Study Reporting, published in December, 2010, the projected energy savings for the Hy-Vee parking lot is 54,621 kWh annually.  The report further communicates the 69.5% power (kW) reduction and visual impacts on the new LED technology.  Alliant Energy surveyed Hy-Vee employees to understand the human perception to the new lighting system. Employees reported no negative observations as compared to the previous metal halide lamps.

Initial before and after photos show that the LED light (right-hand photo) tends to provide greater light dispersal as compared to the current metal halide fixtures. The Metal halide fixtures produced more defined pools of light. Members of the team also discussed how details on vehicles were more visible with the LED lamps.

Before

After

Note the elimination of "dark spots" with new LED fixtures

Notice that the figure is partially covered in the pool of shadows in the first picture.
In the right-hand photo, the figure is clearly visible.

The figure's shirt color and facial features are visible with LED lighting.

Notice more uniform illumination, decreased shadows.

Iowa Energy Center personnel performing light measurements in Hy-Vee's Health Market section.