Operating as an independent agency since 1991, though public housing has existed in the city since the 1930s, the Minneapolis Public Housing Authority (MPHA) owns and operates approximately 5,800 public housing units, administers more than 4,000 Section 8 vouchers, and operates two homeownership programs. As part of its ongoing renovation efforts, MPHA is always looking for ways to be more cost efficient and sustainable. This was the goal that drove the remodeling project at a high-rise senior apartment complex in 2009.

Renovations within the 25-story building included hallways, stairwells, and community rooms that were illuminated 24 hours a day 365 days a year, despite being unoccupied most of the time. The MPHA turned to lighting industry professionals Davis & Associates, Inc., to address this issue and help develop a more energy-efficient solution that still met city building codes.

“The MPHA asked us to research LED lighting as an option, but we felt it was not a viable solution in early 2009,” says Shawn Meyer, LC, LEED A.P. with Davis & Associates. “However, after approaching Lithonia Lighting with the opportunity, we learned about RTLED, which was new to the market. Once we ran photometric reports and energy analysis on the RTLED, we realized it was a superior solution for helping MPHA reduce energy, save on maintenance costs, and achieve its sustainability goals.”

Davis & Associates recommended a lighting redesign using the Lithonia Lighting RTLED with SensorSwitch occupancy controls. However, there were multiple building code challenges MPHA had to overcome in order to implement the LED and occupancy sensor solution. As a result, Lithonia Lighting, Davis & Associates and the MPHA worked closely to design an LED lighting system with occupancy sensors the city would approve.

“Minneapolis building code did not allow occupancy sensors in emergency egress areas, and stairwell lighting needed to be seven times brighter to meet the new building codes,” notes John Plifka, MPHA manager of facilities and development.

Ultimately, the solution included the luminaire paired with occupancy controls that allowed lighting in the common areas, including egress lighting, to be turned off unless someone was in the area. Redundancy was also built into the design to allow MPHA to meet life safety codes. Both the lighting and controls were served from several existing emergency circuits for each of the areas.

“We petitioned the city for a building code variance,” explains Plifka. “The City of Minneapolis conducted an in-depth review and approved the new lighting system.”

Upon approval from the City, the MPHA installed more than 125 LED luminaires and more than 375 LED downlights throughout all public spaces of the high-rise, including common areas like hallways, stairwells, offices, kitchens, boiler room and more.

“Even though the new code required seven times more light, the RTLED fixture paired with occupancy sensors allowed us to significantly reduce our energy use,” says Plifka. “Specifically, our stairwell lighting system is used only when needed, which currently adds up to about three hours a day.”

According to Plifka, the LED lighting and occupancy sensors together helped the facility reduce its energy use by 90% in the stairwells, and the LED fixtures are expected to last 45 years (as predicted with energy analysis tools and later validated with sample data points.) Throughout the entire building, the results of the lighting redesign reduced energy consumption by more than 77%, lowered carbon dioxide emissions by 76%, and slashed maintenance costs by 58%.

MPHA plans to continue installing LED lighting in its facilities as appropriate based on final measured data points.