Back - Project Info  Data Sources  Definitions

  1. Annual Energy Use
  2. Building Definition
  3. Building Type
  4. Climate Zone
  5. Energy Use Intensity (EUI)
  6. Floor Area
  7. Site/Source Energy
Annual Energy Use
The energy use data entered should correspond to the total energy consumed during a recent 12-month period.  All EUIs in the database were calculated from billing data, and normalized to represent a 365-day period.  

Currently the database contains only gas and electric data though some of the buildings in the database may use other fuels, and are separated accordingly.  See the results page for explanation of what buildings are included in each graph.  

Building Definition
By definition, the 'buildings' contained in this database may or may not represent entire buildings, but rather, a business, or premise.  Hence it is useful to compare by floor area.  

Building Type
The building type, or principal building activity, is the only required user input in Cal-Arch.  The default value is Office/Professional.  If you are just browsing and do not have data to enter, you can select a building type and then skip to the end to see what the distribution of EUIs looks like.  If your building falls into  more than one category, select the one that takes up the most floor space.  Future versions may allow you to select multiple building types.

Note that Education: K-12 is wholly included within the Education category. 

Climate Zones
The California Energy Commission recognizes 16 different climate zones in California. Because the sample sizes in some zones are small, particularly when multiple filter criteria are applied, the climate zones have been grouped into 4 climate zones: North Coast, South Coast, Central Valley, and Desert/Mountain. Click on the images below for enlarged view.


If you enter a zip code, only buildings within the same climate zone will be displayed in your results.

Currently Cal-Arch contains data only from the PG&E and SCE electric service territories.  If you enter a zip code and few or no buildings are returned, try again without a zip code, and/or uncheck the floor area filtering checkbox.
Energy Use Intensity (EUI)
This is a measure of total energy use normalized for floor area.  This is used to compare the energy use of different buildings, and is the unit for the x-axis on the histogram displayed in your results.  Whole-building energy use is measured in kBtu (1000 British thermal units) per square foot, per year, to standardize units between fuels.  Electricity use is often expressed as annual kWh per sqft per year. 

Floor Area
By default, if both floor area and energy use are entered, an EUI will be calculated for your building.  Depending on the energy use data entered, separate EUIs will be calculated for electric, gas, and whole-building energy use.  

If you check the floor area checkbox, floor area will be used as a filter variable.  That is, only buildings with the 1/2 to 2 times the floor area entered will be included in your comparison results.

Site/Source Energy
Energy use can be expressed as either site or source energy. Typically site energy, the energy delivered to your building, is reported and billed, and thus it is assumed you are entering your data as site data. In evaluating energy efficiency and environmental impacts of energy consumptions you may be interested in examining Source energy, the energy produced and transmitted from the power plant. The site-to-source conversion factor used in Cal-Arch for electricity is 2.7 (*); Site and Source gas use are nearly the same. The differences are primarily due to transmission losses.

* US Energy Information Administration, CA State Energy Data 2000. http://www.eia.doe.gov/emeu/states/sep_use/total/pdf/use_ca.pdf.


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

We welcome your Comments on this site!