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Interpreting Results

Histograms
Summary Statistics
Is my building efficient?
Export Graphics
Next Steps

Histograms
Cal-Arch results include three histograms (Whole Building, Electricity, Gas) of EUIs for 'comparable' buildings, depending on the criteria you enter.  If you leave all fields blank, the resulting histograms will contain all buildings of the selected activity type. The default building activity is Office/Professional.   If you enter energy use and floor area, green arrows on the appropriate graphs will indicate how your building compares to the ones in the Cal-Arch database.

The default histogram type is a frequency percent histogram. An example using this option is shown below. The x-axis shows the values of the histogram bins, which in figure above, have a width of 10 kbtu/sqft-yr. Bin width may not be modified at this time. The y-axis is percent frequency, that is, the percent of all buildings displayed in a given bin. In this case, your building uses about 42 kBtu/sqft-year and about 11% of the buildings shown use between 40 and 50 kBtu/sqft-year.

image forthcoming
  Histogram

On the Input page, you are given the option to select a Cumulative Frequency Histogram. An example using this option is shown below. In this case the y-axis gives the cumulative percent frequency, that is, the percent of all buildings to the left of a given point. 

In the example shown below, the cumulative percent frequency, corresponding to Your Building is about 45%, i.e., 45% of the comparison buildings use less than 40 kBtu/sqft-yr. kBtu/sqft-yr.

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  Cumulative Histogram

Whole-Building Energy Use Histogram
The whole-building energy use graph includes only buildings in our database for which whole building energy information is available and for which your filter criteria are satisfied.  Currently this includes only all-electric buildings and for PG&E service territory, gas-electric buildings.  At this time we do not have energy consumption information for other fuels.

Electricity Use Histogram
The electricity use graph includes all buildings in our database for which annual electricity consumption information is available, and for which your filter criteria are satisfied.  Currently this includes all locations in the database except for all-electric buildings.  All-electric buildings are included on the Whole-Building Energy graph.  In the future you may be able to view all-electric and gas-electric buildings separately. 

Note if you enter an all-electric building, your EUI will be displayed on the Whole-Building graph.  While the Electricity Use graph will still be displayed, comparisons to electricity use in buildings which use additional fuels for heating would be misleading. 

Natural Gas Use Histogram
The gas use graph includes all buildings in our database for which annual gas consumption information is available, and for which your filter criteria are available.  Gas use information is available only some locations in the PG&E service territory, and thus if no locations with gas data are returned by your query, no gas use information will be displayed.

Summary Statistics

To the right of each histogram, a summary table provides quartile information for the corresponding EUI distribution.  For the Electricity Use graph, EUIs are also given in units of kWh per square foot per year.  If you entered floor area and energy use correponding to the histogram (gas, electric, whole building), then your EUI will be given along with its percentile ranking.  Note: Clicking on "more information" will bring you back to this page.

Additional nformation about the set of comparison buildings will be displayed below the graphs.   An example is shown below.  Clicking on the hyperlinks will provide you with additional information about each field, or go to the Definitions page.  We hope to expand the amount of information on the comparison dataset to include information such as heating and cooling presence, vintage, etc. 

So, is my building efficient?

A low energy use does not necessarily mean your building is efficient and a high energy use does not always mean that it is inefficient.  There are many other building characteristics not included in this tool that may affect your building's energy use.  Factors such as structure, level of service, and occupancy might be different in the buildings represented on the histogram.  Many buildings considered to be efficient still have significant energy savings potential; exact savings measures and potential can be determined by a qualified energy engineer. 

This tool is intended to be a starting point in assessing energy savings potential.  It provides you with a direct comparison to actual data from real California buildings.  We have not adjusted the data in anyway to compensate for differences in buildings.  While there is benefit to doing so, it is not our intention to create a ratings system using this tool. 

Export Graphics

Cal-Arch graphics are generated in png format. To save your images, right-click on the graph and select Save Image As... In some browser versions you can right-click and select Copy to copy the image to your clipboard. You can also highlight the graph as you would text and copy and paste to another application.

Next Steps

Now that you have had a chance to see how some other California buildings perform, see how you measure up to the national stock.  Check our Links page for additional online tools, ratings systems and websites. 
 
 

US ARCH | CBSG | HPCBS | EETD | BTD | LBNL

This project has been funded in part by the California Energy Commission Public
Interest Energy Research program under the
High Performance Commercial
Building Systems project
.

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