Monitored lighting energy savings from dimmable lighting controls in The New York Times Headquarters Building

Abstract

Digital addressable, dimmable lighting controls were introduced to the US market in the early 2000s with the promise of energy savings while allowing greater flexibility than their analog counterpart. The New York Times Company installed this emerging technology, after thorough pre-procurement testing, in their new building in New York, NY. Four years after full occupancy (2007), the owner agreed to participate in post-occupancy monitoring of the lighting system to verify actual performance. Annual lighting energy savings from daylighting, setpoint tuning and occupancy controls were determined for the daylit, open-plan office areas on three typical floors (6th, 11th, and 20th) of the 51-story tower. Energy savings were calculated from data recorded by the lighting control system, after calibration through independent energy consumption measurements. Savings from dimming controls (daylighting and setpoint tuning) were 12.6kWh/m2yr for the daylit spaces on the three floors overall, or 20%, relative to ASHRAE 90.1-2007. Against the prescriptive code in effect at the time of the building's construction (ASHRAE 90.1-2001), savings were 21.0kWh/m2yr or 28%. Annual lighting energy use with all lighting control strategies was 33.9kWh/m2yr in the daylit, open plan zones on average for the three floors. A simple payback analysis was conducted.