Is my building efficient?
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.
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.
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
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.
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.
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
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
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
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
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,
So, is my building
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.
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.
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
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
Building Systems project.
We welcome your Comments on this site!