Created by the U.S. Department of Energy and our partner laboratories, the Home Energy Score is a standard rating system that estimates a home’s energy use based on its “envelope” (foundation, roof, walls, insulation, windows), energy systems, and square footage. A Home Energy Score Assessor collects this information about the home during a one-hour assessment, and then uses the Home Energy Score energy modeling software to estimate the annual energy use of the house based on standard operations and local weather patterns.
What Does Your Score Mean?
The home’s estimated energy use is converted into a score on a 10-point scale, where a score of 1 represents a home with high-energy use, a score of 5 represents a home with average energy use, and a score of 10 represents a home with low energy use.
A low scoring home is likely a great candidate for cost-effective energy improvements, which could not only help homeowners save energy and money, but also improve comfort and indoor air quality, and make the home more attractive when it’s time to sell. Because the Home Energy Score normalizes for differences in weather patterns and associated energy use across the country, it allows for homes to be compared both locally and nationally.
The ten-point scale is determined using 2009 U.S. Census housing data. If a home scores a 5, it is expected to perform comparably to an average home in the U.S. in terms of energy use. If a home scores a 10, it ranks among the ten percent of U.S. homes expected to use the least amount of energy after accounting for local climate. A home scoring a 1 is estimated to consume more energy each year than 85 percent of U.S. homes, again after accounting for local climate.
Data from approximately 1,000 weather stations is used to normalize energy consumption across various climatic conditions. Homes in temperate climates are expected to require less energy for heating and cooling compared to homes in more extreme climates. By accounting for local climate, homes in more extreme climates do not face a disadvantage for using more energy compared to homes in more mild climates. Homes in different climates with the same Home Energy Score are comparable in terms of energy performance.
Converting U.S. Census home energy use data into the Home Energy Score
Scoring Tool Updates
The DOE is in constant communication with our Partners and laboratories to further refine the Scoring Tool. The DOE’s National Renewable Energy Laboratory (NREL) performs analyses to test the Scoring Tool as it is continuously updated. Analysis includes comparisons of the Scoring Tool's energy estimates with actual utility bills from thousands of homes. Read the Summary from our 2014 Report on NREL’s findings.
How We Assure Quality
To ensure a high quality product, DOE conducts systematic reviews of the data provided by Home Energy Score Assessors. Local and national Partners are required to carry out additional quality assurance through on-site reassessment of 5% of homes scored by third-party energy professionals skilled in energy efficiency, energy rating, and evaluation methods. DOE reviews these assessments to ensure Assessors provide scores that are consistent nationally. These reviews are used to provide direct feedback to Assessors and Partners, and to improve DOE’s training modules.