Ascension: Saint Thomas Hospital


Saint Thomas Hospital, a 541-bed acute care facility constructed in 1974, is part of Saint Thomas Health in Nashville, Tennessee, Ascension's four-hospital system. The energy efficiency strategy for Saint Thomas Hospital began in June 2008 and will be an on-going effort. Saint Thomas Hospital is implementing the same program first established at Baptist Hospital, a sister hospital in the same Health Ministry, and is achieving similar results.


Baptist Hospital has been the role model for Saint Thomas Hospital, and began implementing a comprehensive energy efficiency strategy in 2008 and saw impressive results that demanded expansion. In just three-and-a-half years since the energy efficiency program began, Baptist Hospital improved its ENERGY STAR rating from 17 to 65 and reduced its EUI from 275.5 kBtu/sq. ft., to 205.6 kBtu/sq. ft., a 23.6% improvement as well as an 18% reduction in energy costs.



Saint Thomas Hospital has implemented a mix of both low cost behavior change measures, and large-scale infrastructure projects, to obtain significant energy savings. For example, printing out daily weather forecasts and posting them in the Central Energy Plant allows the plant staff to make appropriate decisions about chiller and boiler operations. Infrastructure projects include a series of lighting retrofits in both the garage and hospital lighting fixtures.


Maintenance employees, motivated by the new program, upgraded their skills to monitor and correct equipment conditions found to be outside of expected performance ranges. These are relatively low cost measures, which began in 2008, have produced impressive results. In 2009, an earlier retro-commissioning project identified and corrected deficiencies in the building utility systems, and in 2010 energy efficiency measures included the following:

  • An 800,000 square foot garage lighting retrofit to high efficiency fluorescent fixtures with a daylight harvesting control system.
  • An upgrade of the hospital lighting fixtures with energy efficient T8 fluorescent electronic ballasts and lamps.
  • Programming temperature setbacks in unoccupied procedure rooms.

The current year project is a multi-phase chilled water retrofit to improve both the chilled water and condenser water systems, and future projects will include replacing old and inefficient air handlers throughout the building.



By demonstrating that the successful energy efficiency measures taken at Baptist Hospital also work at Saint Thomas Hospital, Ascension is establishing a model that can be used by other health care organizations. Click the Learn More button for additional details on the steps taken at Baptist Hospital.


Baptist Hospital is a 680 bed acute care facility in Nashville, Tennessee, and served as the model for the approach taken at Saint Thomas Hospital. Originally constructed in the 1950s, it now includes over 1.5 million square feet of space. At the May 2008 baseline, Baptist Hospital had a Weather Normalized Site Energy Use Intensity (EUI) of 275.7 kBtu/sq. ft., with an ENERGY STAR Rating of 17. In October 2011, Baptist Hospital improved its ENERGY STAR Rating to 55 and reduced its EUI to 221.9, a 19.5% improvement in three years. In 2008, Baptist Hospital spent $3.74 on energy per square foot per year. Currently, the hospital spends $3.24 per square foot per year, a decrease of 13% in a time of rising energy costs. This resulted in 67,000 kBtus that were not consumed and over $1 million saved in operating cost over those three years. This translates to 13 tons of carbon dioxide that were not emitted into the atmosphere and $150,000 in direct medical costs avoided for conditions such as bronchitis, asthma and mercury related illness.

Damian Skelton, Executive Director of Facilities for Saint Thomas Health said, “With the financial challenges of healthcare reform, it is not an option to remain with the status quo. We look for every opportunity for energy efficiency improvements.”

Initial projects were funded by reinvestment of savings, along with capital investments from the Ascension Health Facility Infrastructure Pool, a Better Buildings Challenge implementation model. Savings from the initial work were also used to fund a retro-commissioning project in 2009, which identified and corrected deficiencies in the building utility systems.


Annual Energy Use

(Source EUI)
Baseline (2008)
658 kBtu/sq. ft.
Actual (2013)
547 kBtu/sq. ft.

Energy Savings:


Annual Energy Cost

Baseline (2008)
Actual (2013)

Cost Savings:


Sector Type



Nashville, Tennessee

Project Size

1.1 Million Square Feet

Financial Overview

Project Cost $167,400

Saint Thomas Hospital
Saint Thomas Hospital