Data Sources

• Electricity prices -- U.S. Energy Information Administration, Electric Power Monthly Table 5.6.A, residential price by state, fetched weekly
• Gas prices -- EIA average residential natural gas price by state and the heat content of delivered gas, fetched weekly
• Price growth -- Bureau of Labor Statistics CPI-U, electricity (CUUR0000SEHF01) and piped gas (CUUR0000SEHF02), ten years of monthly values
• Efficiency classes -- ENERGY STAR certified product data for refrigerators, freezers, dishwashers, washers and dryers

Each source carries its fetch time in the response and at /v1/data/sources. If a source cannot be refreshed, the last good data is kept and its age is shown.