An easier way to cut energy use from existing buildings

Posted on October 10, 2013

Energy use in existing commercial buildings accounts for 17 percent of U.S. greenhouse gas emissions at a cost of more than $100 billion per year. But it doesn’t have to. On average, 30 percent of the energy that these buildings use is wasted through inefficiencies. Outdated lighting, oversized equipment, and poor operations are just a few culprits.

President Obama has called for American businesses to cut in half the amount of energy they waste in their buildings by 2020. The good news is that over the past two decades, thousands of organizations have already met—and exceeded that challenge—with help from ENERGY STAR®.

Benchmarking is the first step

To start eliminating waste, you first need to know how much energy your buildings use, and whether they are among the best or worst in the nation. Through ENERGY STAR, the U.S. Environmental Protection Agency offers a tool called Portfolio Manager®. ENERGY STAR Portfolio Manager is a free, online energy measurement and tracking tool. Any kind of building can use the tool. Current users include well known structures, such as the Empire State Building and Busch Stadium, as well as the buildings we see in our communities every day: hospitals, elementary schools, supermarkets, and hotels. In fact, more than 300,000 commercial buildings nationwide—or 40 percent of U.S. commercial building space—use Portfolio Manager to assess their energy performance and track improvements. 

Here’s how it works: After setting up a free, secure account, a building enters at least 12 months of utility bill data into the tool (whole-building data from all meters is required), along with certain relevant building and operating characteristics. From there, ENERGY STAR Portfolio Manager calculates nearly 150 metrics on your building’s energy performance, water efficiency, greenhouse gas emissions, and more. You can normalize for weather conditions, compare your building’s performance to the national average, set goals to improve, and then track your progress each month after adding the latest set of utility bills. 

For many building types, Portfolio Manager will also calculate a 1 – 100 ENERGY STAR score, which compares a building’s energy performance to similar facilities nationwide, while normalizing for weather, operations, and building characteristics. A score of 50 represents median energy performance. A score of 75 represents performance better than 75 percent of similar buildings. The ENERGY STAR score is the only performance-based comparative energy efficiency metric currently available on the market.

So how can these metrics help to cut energy waste from American’s existing building stock?  

The power of information

Walk into any commercial building and tell me whether it’s wasting energy. Not sure? What if you looked at the building’s energy bills? Still not sure? What if I told you that the building earned a 1 – 100 ENERGY STAR score of 17? Now we’re talking. More importantly, now we’re motivated to do something about it!  

The more than 300,000 buildings that use ENERGY STAR Portfolio Manager check in on their performance on a regular basis. Like stepping on the bathroom scale every morning, this tells them how they’re doing and whether they’re getting more or less efficient over time. 

In fact, in a recent study, EPA found that buildings that benchmarked their energy use consistently over a three-year period reduced their energy use by seven percent on average (or 2.4 percent per year). And those that started out as poorer performers (ENERGY STAR scores under 50) saved twice as much energy over that three-year period as those who started out above average.  

While we can’t say whether it’s the act of benchmarking that causes these reductions, it stands to reason that the act of benchmarking can help keep energy performance top of mind amidst other competing priorities. In addition, benchmarking can help illuminate a path to improvement. 

Bringing problems to light

The first thing that benchmarking in ENERGY STAR Portfolio Manager will reveal is whether certain buildings within a portfolio are performing differently than others. In cases where the buildings in question are relatively uniform—for example, a group of fire stations—this can signal discrepancies in operations, maintenance, or behavior.

Comparing a building to its peers nationwide and seeing how it ranks can bring to light shortcomings that may have otherwise been overlooked.  Typically, we begin by identifying areas in which a building is wasting energy—by leaving lights and equipment on outside of normal operating hours, for example. Perhaps a building contains highly efficient equipment, but still returns a low ENERGY STAR score. This may signify problems with equipment sizing, controls, or design. By addressing issues like operations, maintenance, and behaviors, buildings can begin to reduce their energy use and chip away at that nearly one-third of energy that’s being wasted and prepare for larger investments in efficient equipment.  

Slow and steady reductions add up

Of the buildings in our study that reduced their energy use, 90 percent demonstrated annual reductions of less than 10 percent. This suggests that, among buildings that consistently benchmark their energy performance, long-term gains in efficiency are achieved slowly and steadily over time (likely through operations, maintenance, and behavior change), rather than through infrequent bouts of large-scale efficiency measures (for example, upgrading heating or cooling equipment). 

If all U.S. buildings followed a similar trend of reducing their energy use by 2.4 percent per year, we could save more than 18 million metric tons of greenhouse gas emissions every year, and we could reduce the amount of energy used by buildings by 25 percent by 2020. 

Stepping on the scale just got easier

For buildings interested in benchmarking with ENERGY STAR Portfolio Manager, there is good news. This year, EPA released a complete upgrade to the tool, which nows makes it easier than ever to get data in, get information out, and share and report data with others. Specifically, users will benefit from: 

Easy data entry:

  • - New data entry wizards to walk you through the process step-by-step.

  • - More Excel import options: simple Excel upload for a single meter, advanced customizable Excel upload for multiple meters.

  • - Improved alert messages - when you enter data that doesn't match, or a meter that has a gap in it, you will see alert messages that call your attention directly to the row with the error.

  • - Simplified sharing to exchange data via web service - it will be easier to find a utility or service provider and authorize them to enter your data automatically.


  • - Ability to search ENERGY STAR Portfolio Manager for other users and form a "connection" like you can on social networking sites.

  • - Once you're connected, you can share multiple properties at once and customize the sharing rights.

  • - The sharing table lets you set access levels for multiple properties and contacts at the same time.


  • - New graphs and table throughout the tool.

  • - Graphs can be easily exported as images for use in your presentations and reports.

  • - Expanded feature to create a big table with your own selected metrics and export to Excel.

Why don't you step on the scale today and start working toward our national goal to reduce our buildings' energy use over the next six years? Take a tour of the new ENERGY STAR Portfolio Manager tool at You can also learn more about our study of more than 35,000 commercial buildings, along with the financial value of benchmarking, at

Authored By:
Lauren Hodges Pitcher is the director of communications for the U.S. Environmental Protection Agency's ENERGY STAR Commercial Buildings and Industrial Plants program. Through ENERGY STAR, Lauren works with public- and private-sector organizations to raise awareness about climate change and the importance of energy efficiency, educate tenants and employees about energy-saving behaviors, and promote the value of ENERGY STAR certification. Prior to joining the U.S. Environmental Protection Agency, Lauren worked in

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October, 10 2013

Harry Valentine says

Iti s certainly a pity that the sulphur-fusion light disappeared from the market . . . a single such light could light the interior of a single building, via fibre-optic transmission system or 'light-pipe' transmission system and 'sunflower' light distribution networks inside buildings. A solar optical collector mounted on top of tall buildings and connected to a fibre-optic (or light-pipe) system can also distribute light inside buildings.

District heating and/or cooling is well proven in many cities and can definitely improve building energy efficiency . . . perhaps connected to distributed electric power generation installations.

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