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The Sustainability Tracking, Assessment & Rating System™ (STARS) is a transparent, self-reporting framework for colleges and universities to measure their sustainability performance.

Overall Rating Silver
Overall Score 58.08
Liaison Kristi Wiedemann
Submission Date March 13, 2015
Executive Letter Download

STARS v2.0

Princeton University
OP-8: Building Energy Consumption

Status Score Responsible Party
Complete 2.04 / 6.00 Thomas Nyquist
Director of Engineering
Engineering and Construction
"---" indicates that no data was submitted for this field

Total building energy consumption, all sources (transportation fuels excluded):
Performance Year Baseline Year
Total building energy consumption 1,675,700 MMBtu 1,710,800 MMBtu

Purchased electricity and steam:
Performance Year Baseline Year
Grid-purchased electricity 300,800 MMBtu 268,700 MMBtu
District steam/hot water 1,159,500 MMBtu 1,223,700 MMBtu

Gross floor area of building space::
Performance Year Baseline Year
Gross floor area 8,912,800 Gross Square Feet 8,158,600 Gross Square Feet

Floor area of energy intensive space, performance year::
Floor Area
Laboratory space 2,897,700 Square Feet
Healthcare space 0 Square Feet
Other energy intensive space

Degree days, performance year (base 65 °F)::
Degree days (see help icon above)
Heating degree days 4,889
Cooling degree days 1,849

Source-site ratios::
Source-Site Ratio (see help icon above)
Grid-purchased electricity 3.14
District steam/hot water 1.52

Start and end dates of the performance year and baseline year (or 3-year periods)::
Start Date End Date
Performance Year July 1, 2011 June 30, 2014
Baseline Year July 1, 2005 June 30, 2006

A brief description of when and why the building energy consumption baseline was adopted:

The baseline was adopted because this timeframe was prior to the inception of the University’s Sustainability Plan in 2007-2008.


A brief description of any building temperature standards employed by the institution:

The University uses full distributed digital control (DDC) systems in about 150 buildings on campus, which includes all of the heaviest energy-use buildings. Each building’s spaces have schedules each day to ensure that systems are off for spaces that are unoccupied.


A brief description of any light emitting diode (LED) lighting employed by the institution:

Starting in summer of 2014, Princeton University began to upgrade over 100,000 lighting fixtures in nearly every campus building to light emitting diodes (LEDs) lighting. Princeton estimates that this conversion will reduce the University’s energy usage by nearly 3 megawatts and its carbon dioxide emissions by nearly 10,000 metric tons every year.

Before the campus-wide LED conversion, the University used LEDs for street lighting, conference rooms, audiovisual rooms, wall washing, and downlighting.


A brief description of any occupancy and/or vacancy sensors employed by the institution:

The University uses a variety of occupancy sensor technologies, including dual technology, vacancy sensors, wireless sensors, and light level (i.e. daylight harvesting) sensors.


A brief description of any passive solar heating employed by the institution:
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A brief description of any ground-source heat pumps employed by the institution:

Princeton's first ground source heat (“geothermal”) pump system installed in 2003 was one of the most extensive in New Jersey, serving 200 units at Lawrence Apartments. Additionally, Campus Club is also heated and cooled in this way.

Princeton is moving forward in including geothermal systems with selected new construction projects. Due to be completed in 2015, the new Lakeside Graduate Housing complex will be equipped with a geothermal system. Additionally, the Arts and Transit Project, due to be completed in 2017, will also use a geothermal system.


A brief description of any cogeneration technologies employed by the institution:

The electric generator, powered by a General Electric LM-1600 gas turbine that burns natural gas or diesel fuel, is a cogeneration facility. What would normally be wasted exhaust heat from the turbine is recovered to heat water and make steam. Through cogeneration and other waste heat recovery, the efficiency of Princeton’s plant rises to the range of 80 percent vs. 25-40 percent for a typical utility energy plant. The cogeneration plant can generate 15 megawatts of electricity, about equal to Princeton’s average electricity needs on a given day. The Princeton turbine was the first of its kind in the world to earn certification to operate on bio-diesel fuel.


A brief description of any building recommissioning or retrofit program employed by the institution:

There are numerous building recommissioning and retrofit programs underway at Princeton. A few examples include:
-In fiscal year 2014, control system optimization was installed in 40 buildings. A total of 28 buildings remain to be completed of the top 40 buildings.
-In 2013, Princeton completed a renewal of Jadwin Hall, which included renovated its HVAC systems to become more efficient. The renovated HVAC system will save approximately 1,950 metric tons of emissions per year. The project also included energy efficient lighting and building controls and energy efficient windows.
-Firestone Library is undergoing a complete renovation and reconfiguration as a 10 year project. Upon completion, Firestone Library will be equipped with an energy-efficient HVAC system, energy-efficient lighting, replaced skylight glazing, low-flow plumbing fixtures, and upgraded building finishes.


A brief description of any energy metering and management systems employed by the institution:

For electrical meters, three-phase power meters are used. For steam meters, inline vortex shedding meters with pressure compensation are used. For chilled water meters, the University uses magnetic type meters and ultrasonic flow meters. These meters provide real-time information to campus operators.


A brief description of the institution's program to replace energy-consuming appliances, equipment and systems with high efficiency alternatives:

The University has a commitment to replace energy-consuming appliances, equipment, and systems with high-efficiency alternatives when possible. For example, the University has already replaced many of its campus dishwashers and laundry machines with high-efficiency alternatives, and is currently replacing most of its campus lighting with LED bulbs.


A brief description of any energy-efficient landscape design initiatives employed by the institution:

Historically, Princeton has irrigated minimally on campus, instead relying on robust plantings that require little maintenance, chemical input, and watering. This approach is a historically sustainable one, requiring far less fossil fuel input than extensive annual or sensitive specialty plantings. While limited specialty plantings are an integral part of the campus character, Princeton will maintain its traditional approach to general landscaping. Princeton emphasizes: preserving native soils, increasing pervious surfaces, installing plantings adapted to the local climate and soil types that require minimal maintenance, favoring organic approaches, and irrigating as an exception rather than a rule.


A brief description of any vending machine sensors, lightless machines, or LED-lit machines employed by the institution:

Energy-saving motion sensors have been installed in some University vending machines. These motion sensors activate the vending machine when a person requires service.


A brief description of other energy conservation and efficiency initiatives employed by the institution:
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The website URL where information about the institution’s energy conservation and efficiency initiatives is available:

Since 2005, Princeton University's campus square footage has grown by about 800,000 square feet. Despite this growth, Princeton's total building energy consumption is nearly the same as it was in 2005 due to campus-wide efficiency improvements, which are described further in this section.

The information presented here is self-reported. While AASHE staff review portions of all STARS reports and institutions are welcome to seek additional forms of review, the data in STARS reports are not verified by AASHE. If you believe any of this information is erroneous or inconsistent with credit criteria, please review the process for inquiring about the information reported by an institution and complete the Data Inquiry Form.