Overall Rating Silver
Overall Score 52.25
Liaison Alex Miller
Submission Date March 20, 2018
Executive Letter Download

STARS v2.1

Carleton College
OP-5: Building Energy Consumption

Status Score Responsible Party
Complete 3.55 / 6.00 Martha Larson
Manager of Campus Energy and Sustainbility
"---" indicates that no data was submitted for this field

Figures needed to determine total building energy consumption:
Performance Year Baseline Year
Grid-purchased electricity 45,391 MMBtu 48,811 MMBtu
Electricity from on-site renewables 13,882 MMBtu 0 MMBtu
District steam/hot water (sourced from offsite) 147,684 MMBtu 156,288 MMBtu
Energy from all other sources (e.g., natural gas, fuel oil, propane/LPG, district chilled water, coal/coke, biomass) 0 MMBtu 0 MMBtu
Total 206,957 MMBtu 205,099 MMBtu

Start and end dates of the performance year and baseline year (or 3-year periods):
Start Date End Date
Performance Year July 1, 2016 June 30, 2017
Baseline Year July 1, 2007 June 30, 2008

A brief description of when and why the building energy consumption baseline was adopted (e.g. in sustainability plans and policies or in the context of other reporting obligations):

The baseline corresponds with Carleton's first greenhouse gas inventory that was aided and verified by Sightlines, a facilities benchmarking and analysis firm.

Gross floor area of building space:
Performance Year Baseline Year
Gross floor area of building space 1,927,731 Gross Square Feet 1,680,023 Gross Square Feet

Source-site ratio for grid-purchased electricity:

Total building energy consumption per unit of floor area:
Performance Year Baseline Year
Site energy 0.11 MMBtu / GSF 0.12 MMBtu / GSF
Source energy 0.17 MMBtu / GSF 0.20 MMBtu / GSF

Percentage reduction in total building energy consumption (source energy) per unit of floor area from baseline:

Degree days, performance year (base 65 °F / 18 °C):
Degree days (see help icon above)
Heating degree days 6,689 Degree-Days (°F)
Cooling degree days 845 Degree-Days (°F)

Floor area of energy intensive space, performance year:
Floor Area
Laboratory space 62,910 Square Feet
Healthcare space 550 Square Feet
Other energy intensive space

EUI-adjusted floor area, performance year:
2,132,283 Gross Square Feet

Building energy consumption (site energy) per unit of EUI-adjusted floor area per degree day, performance year:
12.88 Btu / GSF / Degree-Day (°F)

Documentation (e.g. spreadsheet or utility records) to support the performance year energy consumption figures reported above:

A brief description of the institution's initiatives to shift individual attitudes and practices in regard to energy efficiency (e.g. outreach and education efforts):

A brief description of energy use standards and controls employed by the institution (e.g. building temperature standards, occupancy and vacancy sensors):

Campus standard is 68 degrees in winter 74 degrees in summer. Each week, Carleton's HVAC technicians enter the weekly classroom and office room schedule information into the Building Automation System so temperature setbacks can be employed during unoccupied hours.

A brief description of Light Emitting Diode (LED) lighting and other energy-efficient lighting strategies employed by the institution:

LED retrofit kits and new LED lights are now the standard for the Carleton maintenance department. Our current efforts are low-wattage LED lights with occupancy sensors in enclosed stairwells so they can be reduced to minimum footcandles when unoccupied. Carleton recently replaced over 100 highly inefficient MR16 light bulbs with LEDs in our language and dining facility and one section of the Gould Library. Exterior wall packs are being replaced by LED fixtures as they burn out. We are also beginning to install bi-level LED light fixtures with occupancy sensors in all enclosed stairwells. Furthermore, all underwater pool lights in our two swimming facilities have been replaced with LED lights this summer.

A brief description of passive solar heating, geothermal systems, and related strategies employed by the institution:

None at this time.

A brief description of co-generation employed by the institution, e.g. combined heat and power (CHP):

None at this time.

A brief description of the institution's initiatives to replace energy-consuming appliances, equipment and systems with high efficiency alternatives (e.g. building re-commissioning or retrofit programs):

Carleton has engaged professional engineering firms to perform ASHRAE Level 2 energy audits on ten primary campus buildings. Audits focused on high energy users such as athletic buildings, science building and dining facilities. Audit efforts continue, with the goal of auditing all building on the district energy system within 5-6 years.

The website URL where information about the programs or initiatives is available:
Additional documentation to support the submission:

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.