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Tracking and Measuring Energy Use

Tracking and measuring the energy used by a hospital is the first step a hospital must take to begin its energy management program.  Whether a hospital leases or owns a building it is imperative that it has accurate energy tracking tools in place to identify under-performing buildings, verify efficiency improvements and prioritize investment opportunities. 

EnergyStar’s Portfolio Manager tool is the most commonly used tracking system for energy across the sector. Portfolio Manager helps you track and assess energy and water consumption within individual buildings as well as across an entire building portfolio. Enter energy consumption and cost data into the organization's Portfolio Manager account to benchmark building energy performance, assess energy management goals over time, and identify strategic opportunities for savings and recognition opportunities. EPA has developed a Benchmarking Starter Kit to help facilities get started quickly.


Benchmarking is an assessment approach in which energy-related metrics measured or estimated at one facility are compared to those from other facilities and/or specific performance targets.  Metrics can be specified at the level of a facility, a building, a functional area within a building or specific systems or operations. Benchmarks can be derived from distributions of metric values obtained from facilities having similar functionality or characteristics, from engineering analysis or building simulation modeling, or from expert knowledge of standard and best practices.

Metrics should be developed to make comparisons among facilities as relevant and meaningful as possible. This is accomplished by limiting the comparison group (e.g., inpatient facilities that provide acute care services) or by use of metrics that are normalized or otherwise adjusted by essentially uncontrollable determinants of energy use. To account for the single most important determinant – facility size – total annual energy use is divided by the floor area to calculate energy intensity in units of thousands of British thermal units or watt-hours per square foot per year (kBtu/sf-yr or kWh/sf-yr). Other factors that have a first order effect on energy are climate, weather, operating schedule, and the suite of activities occurring within the facility. Accounting for these factors is discussed below.

The common starting point for facility benchmarking is energy use information from utility and fuel bills. These provide the cost and amount of each type of energy (electricity, natural gas, fuel oil, etc.) used at the site on a monthly basis. The next step is to identify the buildings served by each supply of energy, as described in more detail below. Assuming for the moment the simplest case of a hospital building with a dedicated central plant, the supplied energy (from utility bills) can be divided by floor area to calculate site energy intensities for electricity (kWh/sf-yr), all fuels including natural gas and oil (kBtu/sf-yr), and all forms of energy used on site (kBtu/sf-yr, obtained by converting electric energy into kBtu).  Furthermore, hospitals will also calculate their energy intensity in terms of adjusted patient days (kBtu/APD; kWh/APD).

US Health Care’s Energy Intensity

The national average for the United States healthcare sector's energy intensity is 187 kBtu/SF (Thousand British thermal units per square foot).  Using these metrics as a reference are a great first step for hospitals to evaluate their facilities energy consumption.  Utilize these data below to accurately compare your institution with the corresponding geography.


Energy Intensity (Thousand Btu per Square Foot)









U.S. Commercial Buildings Energy Intensity Using Weather-AdjustedSite Energy1by Census Region and Principal Building Activity, 2003 (Thousand Btu per Square Foot)

Energy Impact Calculator

As pressure for institutional transparency increases, “brown” energy may well be seen as carrying significant health costs and risks. By comparison, energy efficiency and clean energy have advantages with respect to health, regulatory compliance, reliability, community benefits, reputation, fiduciary responsibility, liability, and climate change. What are your facility’s energy health impacts and costs? What can you do to improve them?

Based on US EPA analysis of health impacts of power plant emissions of sulphur dioxide, nitrous oxide and mercury, the Healthcare Energy Impact Calculator (EIC) estimates premature deaths, chronic bronchitis, asthma attacks, emergency room visits and more, by kilowatt hour per year. The EIC displays the projected number of incidents, estimates of medical treatment costs, their external societal costs, and the likely emissions permit costs for the green house gas carbon dioxide.

Calculate how your energy use impacts health

Energy facts from the 2010 Environmental Excellence Awards Sustainability Benchmark Report

Partner for Change Award Winners:

  • 57% are Energy Star Partners;
  • 82% engaged in energy efficiency projects;
  • The entire group (114 hospitals) saved a cumulative total of 47.3 million kWh and $4.9 million from energy efficiency projects.

Environmental Leadership Circle Winners:

  • The entire group saved a cumulative total of 234 million gallons water resulting from those projects.
  • 75% are EnergyStar Partners;
  • 88% engaged in energy efficiency projects;
  • The group (24 hospitals) saved a cumulative total of 39.1 million kWh and $3.4 million from energy efficiency projects.

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