March 18, 1999

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BERKELEY, CA -- Homeowners can save hundreds of dollars per year on their energy bills. How? By using the Home Energy Saver website at

Developed by researchers at the U.S. Department of Energy's Lawrence Berkeley National Laboratory (Berkeley Lab), the Home Energy Saver (HES) website brings advanced building simulation software to interactive World Wide Web pages to help consumers identify the technologies that will save them the most energy and money. By logging onto this site, you can, for example, quickly determine how much money you would save by installing insulation in your attic, and where you would find the best products and a good contractor to do the job.


The HES site is divided into two main sections, "Energy Adviser" and "Making it Happen." Energy Advisor computes a home's total energy use based on information that you enter. Once you supply your zip code, Energy Advisor will show you the energy use, bills, or energy-related carbon dioxide emissions for your area's typical house, and a comparable energy-efficient house. You can then answer a set of basic questions about your own house, including its floor area, the number of occupants, type of heating and air conditioning equipment, and fuel prices, to get a custom-tailored energy bill breakdown. The more information entered, the more these recommendations become tailored to the house.

Energy Adviser also provides a customized set of energy-saving improvements for your house. These improvements cover all of your home's major energy-using systems: space heating and cooling, water heating, lighting, major appliances, and a host of 'miscellaneous' appliances that are an increasingly important factor in residential energy bills.

Making It Happen provides time-saving links to hundreds of Internet sites with practical, detailed information about energy-efficient homes, products, service providers, utility programs, and on-line reading materials. An Answer Desk feature provides answers to frequently asked questions about home energy use in terms that the average homeowner can understand. This module also provides context-sensitive help and email access to energy experts who answer questions from users.

"The Home Energy Saver represents a fundamental departure from previous energy calculators because it is Web-based. The site brings together in one user-friendly package the analytical capabilities of many sophisticated calculation methods," says Evan Mills, Home Energy Saver project leader and a researcher in Berkeley Lab's Environmental Energy Technologies Division (EETD).

"It would take a user months to learn how to use each program separately. The site overcomes the limitations of traditional disk-based software tools, since the power of the Web allows us to implement frequent software and interface upgrades, provide a hospitable environment for both PC and Mac users, and offer a rich array of consumer decision-support information through links to useful related web sites. And since it is Web-based, there is no software to install. Until now, tools like this have been beyond the reach of ordinary consumers. This is a big step forward from the static, generic information normally provided to consumers," Mills explains.

Adds Rich Brown, EETD researcher and Home Energy Saver's production manager, "HES performs heating and cooling calculations using DOE-2, a building energy simulation program developed at Berkeley Lab. Although it's considered the most accurate and powerful program among professional engineers and architects for building energy simulation, until now DOE-2 required extensive training and fast computers. The other energy calculations in HES are also based on models and data from years of research at Berkeley Lab on how people use energy in their homes, for example, the types of appliances and equipment in homes, as well as use patterns. Because HES tailors its results to each house, it helps consumers understand how energy is used in his or her own home compared to local averages and the best ways to reduce that usage."

Consumers are advised that high traffic volume on the HES site occasionally may cause delays or temporary site unavailability. In this event, they should wait a few minutes before trying again. The Berkeley Lab development team is improving the site and adding computing power to handle the growing load of HES users.

Berkeley Lab researchers developed the HES Internet site for the ENERGY STAR Program, an initiative of the U.S. Environmental Protection Agency and DOE.

Berkeley Lab is a DOE national laboratory located in Berkeley, California. It conducts unclassified research and is managed by the University of California.