Reducing Energy Consumption: The Role of Lighting
A key component of Sustainability in any setting is to reduce energy consumption (fuels and electrical). Recall that power-generating plants consume carbon fuels to operate, contributing to greenhouse gas (GHG) emissions. It is estimated that lighting accounts for approximately 12% of electrical use nationwide and 27% in New York City. Reducing energy consumption by lighting has significant impact in terms of energy costs and GHG emissions.
Reduction of electrical usage is accomplished by a variety of means, which can be grouped into three primary types of approaches: replacing existing equipment with more energy-efficient lighting, using lighting only when occupants are present in a space, and Daylight Harvesting.
Installation of energy-efficient lighting. Different types of lamps (i.e. light bulbs) require vastly different amounts of wattage to produce the same amount of illumination. Electrical energy supplied to the lamp is used by the lamp to generate light - and heat, as a by-product. The more energy-efficient the lamp, the less heat and more light it generates. Click here for an energy comparison of incandescent, fluorescent, Light Emitting Diode (LED), and halogen lamps.
New light fixtures with energy-efficient lamps have been installed in many locations throughout the Lehman College campus, taking into account specific use and maintenance considerations of each location and application. Selection and installation was accomplished through a joint effort between Campus Planning & Facilities, Buildings & Grounds, campus electricians, and the end users. The following lighting projects have been completed, are underway, or pending:
- In 2010, 32-watt fluorescent lamps in the tunnel between the Music Building and Davis were replaced with 15-watt LED lamps, providing more illumination, greater energy efficiency and a longer service life (LEDs have not needed to be changed since they were installed);
- 4-Watt LED lamps have been installed in the Faculty Dining Room (can also be dimmed - another way to conserve electricity);
- 250-Watt metal-halide lamps in the outdoor lighting in front of the Bookstore have been replaced with LED lamps (68-92-Watts); other outdoor lighting along College Walk will be replaced with LEDs as well;
- 400-Watt metal halide lamps in the ceiling of the Main Gym of the Old Gym building were replaced with high-bay fluorescent fixtures equipped with motion sensors;
- Outdoor lighting using Mercury-vapor lamps will be replaced with fluorescent lamps;
- Pending (late 2013) floodlights in gallery will be changed from 90-watt halogen lamps to 19-watt LEDs;
- LED lamps/light fixtures have been installed in the Fine Arts Building:
- 400-watt metal halide lamps have been replaced with 78-watt LED flood lamps
- 175-watt metal halide have been replaced with 52-watt LED lamps
- 50 Parabolic Aluminized Reflector (PAR) 20 Incandescent recessed lamps have been replaced with 14-watt energy star LED PAR 30 lamps
- 60 PAR 16 incandescent lamps have been replaced with 9-watt energy star LED PAR 20 lamps
- PAR 38 Flood 90-watt incandescent have been replaced with 17-watt energy star LED PAR 38 lamps
- Fluorescent lighting is being replaced with LEDs in all hallways and stairwells (in progress).
Motion-activated sensors to turn on/off lights. In many campus locations, lights are normally left on until they are manually turned off by the occupants of the space upon leaving. For this reason, spaces that are occupied sporadically throughout the day can be equipped with motion-activated controls that automatically turn on and off lights. Sensors have been installed in all restrooms, classrooms and offices in all buildings at Lehman College. Campus buildings typically shut down at 11 pm, non-essential lighting can be automatically shut down as well, leaving on emergency lighting only. This approach is planned for the hallways in Carman Hall.
By making an adjustment to the cleaning schedule from after hours to evening hours, we have been able to completely turn off lights overnight (midnight to 6 am) in the Library, Old Gym and Student Life Buildings.
Daylight harvesting. This approach uses natural daylight to supplement artificial lighting, and is used throughout Science Hall. Sensors are installed that regulate the amount of light supplied by electrical lighting, so that lighting near the windows is dimmed, or shut off completely, and lighting that is further away from the windows is brighter. Spaces with “window walls” are good candidates for daylight harvesting. This approach has to be balanced against strong outdoor sunlight overheating a space; heat-resistant window shades that allow light through, but block direct sunlight have been installed as well (Carman 3rd floor classrooms).
Last modified: Dec 6, 2013