How to Benchmark Your Buildings

Posted by Anna Jursik  |  Date April 2, 2013

This guest blog by Angela Vreeland, a Mechanical Engineer with CEE’s EBCx program, begins a four part series looking at how building operators can deliver commercial building energy efficiency savings. These posts are based on lessons learned in real buildings through EBCx, and could serve as resources to other organizations working directly with facilities managers.

You want to reduce energy use in your facility but how do you get started?  Whether you manage a school, office building, correctional facility, or manufacturing plant, this blog (along with the rest in this series) will help you answer that question.

Congratulations!  You’ve taken the first (and probably the most) important step in reducing energy use…  You asked the question, “How do I get started?” There is an order by which energy activities should be taken and doing them in order is important to ensure your efforts are cost-effective and save as much energy as possible.

By thinking things through before taking action, you are off to a good start. Now, let’s get to that list…. 

Four Steps to Reduce Energy Use in your Facility:

1. Benchmark your Building(s)
2. Optimize What You Have
          a. Existing Building and Ongoing Commissioning
          b. Behavioral Changes/Initiatives
3. Invest in What You Don’t Have
          a. Lighting Controls/Upgrades
          b. Deep Energy Retrofits
4. Energy Production

This blog will cover Step 1- Benchmarking. Three more blogs (to come) will discuss the next three steps.

Put simply, benchmarking is a process that compares the energy performance of one building to a set of other similar buildings. In an earlier post, Christie Traczyk and Chris Plum explained that benchmarking itself does not save energy. But it does give you an idea of how well your building is doing, and as a result, whether taking the next steps will impact its performance. This will help you down the road, when you’re deciding whether or not to spend money on energy-saving projects.

A relatively quickway to benchmark your building is to calculate its Energy Use Intensity, or EUI.  EUI represents the amount of energy a building uses relative to its size.  It is simply a ratio of energy use, in kBtu, to the total conditioned square footage of the building.  Don’t include unheated garages when calculating the square footage.  That’s cheating.



The equation is very simple, but most time will be spent calculating the energy use in kBtu. It includes all forms of energy, or fuel, that goes into a building such as electricity, natural gas, fuel oil, etc. This information can be found on utility bills and is then added up for the previous year. Once the annual use of each fuel is summed up, the totals need to be converted to kBtu and summed together to get the total energy use in kBtu. Here are the multipliers that can be used for the more typical forms of energy:
 

 
The following table is a list of the average EUI by building type and U.S. climate region. You can use it to see how your building compares to buildings throughout the U.S.:

* indicates insufficient data.

Comparing your building to the average EUI is a good starting point, but this method doesn’t account for factors such as climate, occupancy, and operating conditions.

A more “official” benchmarking method is ENERGY STAR, a program administered by the US Environmental Protection Agency that compares your building to other similar buildings in the same climate region. You enter information about the facility such as operating conditions and occupancy patterns into ENERGY STAR’s Portfolio Manager. Scores range from 0 to 100, where 100 is the best, and buildings with a score of 75 or higher can earn the ENERGY STAR. You can get a score by entering information into the Portfolio Manager yourself, but to qualify for the ENERGY STAR. the inputs must first be verified by a professional engineer or registered architect.  If you find out that your building qualifies for ENERGY STAR, then you know that your building is performing well and additional efforts to saveenergy can be successful, but probably will not yield huge savings. On the other hand, if your building scores below 75, investing in energy improvements is a no brainer.

If you manage multiple facilities, benchmarking can help identify the worst and best performers and target the buildings with the most potential. Until next time, gather up your utility bills, get out a calculator, and benchmark your buildings. See you at Step 2- Optimize What You Have.