Iowa government building slashes electrical load 70% with Acuity lighting and controls

Dec. 20, 2012
Lithonia LED-based RT Series luminaires, Peerless direct/indirect fluorescent fixtures, and nLight adaptive controls combine in the Iowa Public Employees' Retirement System building to deliver 70% energy savings.

The Iowa Public Employees' Retirement System (IPERS) hoped to move its headquarters building in Des Moines, IA toward a goal of operating as a net-zero energy building when it undertook a $4.4 million renovation that included a transition to an intelligent lighting system. Lighting fixtures from Lithonia Lighting and Peerless, and adaptive controls from nLight, all Acuity Brands, are now delivering 70% energy savings in the 43,000-ft2 building.

Recessed RT Series luminaires light the IPERS work spaces

It's a combination of efficient sources and adaptive controls that deliver the reduction in energy usage. The Lithonia products are based on efficient LED sources while the Peerless products use high-efficiency fluorescent lamps and ballasts.

Multidisciplinary consultancy Key Professional Engineers was instrumental in the project and performed an energy audit of the facility. "We decided to specify Acuity Brands products because of the indoor ambient LED lighting option," said Brad Lauritsen of the consulting firm. "The RT Series luminaire from Lithonia Lighting neatly integrates with nLight technology to create a total solution from a single supplier."

Indeed, the primary luminaires used for lighting in the facility come from the LED-based RT Series from Lithonia Lighting. The recessed solid-state lighting (SSL) troffers are a replacement for legacy fluorescent troffers. You can see the luminaires installed in the drop ceilings in the photos that accompany this article. The products come in 1×4-, 2×4-, and 2×2-ft versions.

Suspended Peerless Prima fixtures in conference rooms

The nLight controls are an option on the RT Series of products. The nLight technology uses Cat-5 cables, like the cables used in computer networks, to connect luminaires in both structured and daisy-chained topologies. The network of light fixtures ultimately connects to an Ethernet computer data network that can transmit control commands from a software console to individual fixtures or groups of fixtures.

The lighting retrofit includes the Peerless Prima indirect/direct fluorescent fixtures in spaces such as conference rooms. The suspended luminaires can both use the ceiling to uniformly spread soft ambient light throughout the room and provide direct task lighting on work surfaces such as conference tables.

IPERS has already documented significant savings from the lighting retrofit. After three months of usage, the agency has realized a $12,000 reduction in energy costs relative to the same three months the prior year.