The Home Energy Saver project includes both the HES websites and the API that provides the underlying calculation engine. The Home Energy Saver websites are intended to provide consumers and building professionals with a simple way to use state-of-the-art residential energy calculation tools and energy data. The site integrates a variety of models, algorithms, and data sources developed over several decades at Lawrence Berkeley National Laboratory, other DOE National Labs, utilities, and elsewhere in the energy community. Historically, access to and use of such materials has been limited by the need for specialized expertise, including knowledge of energy and building technologies or computer simulation programming. Making these tools and information available via a web-based interface, enables lay users to obtain energy use and savings estimates tailored to their particular home, climate, and lifestyles.

Development of the Home Energy Saver began in 1994, and the site first went on-line in 1996, originally sponsored by the ENERGY STAR program, operated by EPA and DOE (Mills 1997)2. The Home Energy Saver uses state-of-the-art data and models to support the Federal energy mission by helping to build national recognition of Federal energy efficiency programs and by enabling consumers to quantify the energy savings and environmental benefits that can be achieved by improving the energy efficiency of their home. The site is also used by researchers, designers and contractors as a tool for analyzing residential energy performance issues, and for learning from actual homeowners about their experiences with implementing energy-saving upgrades.

There are two versions of the Home Energy Saver; HES consumer and HES professional. The two versions use identical calculation methods and the content differs mostly in the ancillary materials. Future plans are to differentiate the two sites more with consumer offering quick view inputs and professional emphasizing the detailed approach; version 2 of HES pro is tentatively projected for Q2 2015.