Home Energy Saver

Home Energy Saver logo.

First Internet-based decision-support tool for calculating energy use for all end uses in residential buildings. The Home Energy Saver computes the home's energy use on-line based on methods developed at Lawrence Berkeley National Laboratory (including DOE-2 for HVAC calculations) and quickly relays the results back to the user. Separate modules are provided for heating/cooling, domestic hot water, appliances and miscellaneous uses, and lighting. By simply changing one or more features, users can estimate how much energy can be saved by implementing energy-efficiency improvements.

In addition to calculating energy use on-line, the Home Energy Saver's Librarian connects users to an expanding array of hundreds of other web sites providing nformation on energy-efficient products, home builders, residential utility programs, practical newsletters, energy software, and other useful topics.

The interactive Internet-based approach overcomes a variety of problems endemic to traditional disk-based tools.


internet-based energy simulation, residential buildings



Expertise Required

Designed for the lay person, but also useful to energy analysts.


Utilized on-line via the Internet; thus, number of users varies. Visitation to the site as of early 1997 was ~500 per day.


Homeowners, utilities, residential building professionals, equipment vendors.


Basic descriptions of the home and end-use devices, entered into simple web-based forms. Descriptions are stored on server and may be recalled by users.


Easy-to-understand web pages with graphic and tabular representation of annual energy consumption and costs, by end use.

Computer Platform

Any computer that is capable of running a forms-based web browser.

Programming Language

HTML interface to interactive calculation routines written in FORTRAN. Data collected by a Tango common gateway interface (CGI) and archived by a Butler database management system. HVAC calculations performed via a full DOE-2 simulation, operated by a Visual Basic CGI. Other end use calculations (white appliances, lighting, domestic hot water, miscellaneous uses, etc.) based on LBNL algorithms and databases documented within the site.


This Web-based approach has distinct advantages over the ordinary software production and distribution process. Users benefit from a dynamic and expanding web-based information network unparalleled by resources that could be published on a CD or other static electronic media. Given the sophistication of Web development tools, the user interface can be designed (and subsequently modified) with considerably reduced effort, compared to traditional methods, and thus lower cost. There is only a minimal cost to distribute the product, given that it is available via the Web to all interested users. Furthermore, given that the tool resides on a single server, refinements or additions to the program do not require physical re-distribution or reinstallation of the software or documentation. By virtue of being available via the Web, any user (PC, MAC, etc.) with a forms-enabled Web browser can be guaranteed a seamless user interface free of compatibility issues and complicated installation procedures. Very powerful computational "engines" residing on the host server (DOE-2 in this case) can be used by people who would otherwise lack the necessary computing power.


Limited variety of building types and control of engineering parameters. Condensed output information, rather than detailed hourly or monthly values. Calculations not automatically calibrated to measured consumption. Current version supports only residential buildings analysis. Requires Internet connection.



Center for Building Science
Environmental Energ


Lawrence Berkeley National Laboratory
Building 90
Berkeley, California 94720
United States


(510) 486-6784


(510) 489-6996






The tool may be utilized by visiting the Home Energy Saver web site.