Application Programming Interface ("APIs") services
are available with HEScore for third-party energy software developers to embed the HEScore method into their products and business processes
An asset rating seeks to evaluate a home, allowing it to be compared to other homes based on differences in fixed characteristics while holding occupant-determined factors and behaviors constant. An asset rating also excludes energy by employing features that are not considered fixed components of the building. Thus, a furnace's efficiency would be regarded as an asset attribute, while the thermostat controlling that furnace would be deemed a behavioral (non-asset) attribute. There is some subjectivity in determining which energy-using components of a home are "assets." For HEScore, space-conditioning and water-heating systems (and the associated building envelope components) are assets, while non-hardwired appliances, lighting, and other equipment (and their use) are not.
To ensure users proactively define asset characteristics, no input values are defaulted, and all questions must be answered. For systems not considered fixed assets, attributes are not adjustable and set consistent with those used in the Home Energy Saver software suite (documented elsewhere in this Wiki). HEScore provides an asset calculation with limited application for informing occupants how to operate their homes optimally. For that reason, any HEScore session input may automatically be imported into Home Energy Saver (hes.lbl.gov
) or Home Energy Saver Pro (hespro.lbl.gov
). These tools allow homeowners or contracted energy professionals to consider the home's operational/behavioral aspects, as well as evaluate ancillary energy-using devices, such as pools, wells, or second refrigerators, not included in the standardized asset score.
To fully reflect the value of asset-based upgrades, scores are computed based on the energy use associated with those features, essentially heating, cooling, and water-heating.
Fixed Assumptions and Default Values
For an asset rating to have meaning in the marketplace, one home must be comparable to another. For home characteristics NOT individually recorded and entered into the HEScore tool, non-asset related inputs are standardized to a nationally consistent set. The main differences between the HEScore default values and the Home Energy Saver are described on the defaults
HEScore has five simple pages of user inputs used to describe the home construction and equipment, described in detail on the HEScore User Interface page
. If the home has the same window and wall types on each building side, the total number of required inputs typically is less than 50. Exact wordings along with a more detailed log of questions and required inputs are included in the checklist here
must be considered for each home (variations in which are recommended as a function of home characteristics, cost-effectiveness, etc.). Upgrades considered in HEScore include improvements to the home envelope and major equipment (the "assets") but not to lighting and appliances upgrades or use changes. Unlike other Home Energy Saver tools, HEScore applies a fixed, standardized retrofit cost (from the NREL National Residential Efficiency Measures Database) and generates recommendations, providing the highest performance level with a payback time of 10 years or less. Energy savings are achieved by moving between the baseline home and the deemed efficiency level of the upgrade. General information on "non-asset" upgrades is provided in a "Tips" sheet attached to the Home Energy Score Label.