Data methodology and limits

The price benchmark comes from the EIA weekly residential propane series for Colorado.

What is an EIA series?

EIA stands for the U.S. Energy Information Administration, a federal energy statistics agency. A series is a sequence of measurements of the same thing over time. We use its weekly Colorado residential propane survey average, measured in dollars per gallon.

The identifier W_EPLLPA_PRS_SCO_DPG is EIA’s lookup code for this dataset, not a price or a supplier. Each observation pairs a survey date with a statewide average; comparing those observations produces the price history.

Survey schedule

EIA states its heating-fuel survey runs October through March, with releases on Wednesdays after 1 p.m. Eastern, shifted around holidays.

How this site refreshes

The site refreshes Thursdays at 18:00 UTC. If the host was asleep, it catches up on the next startup or request. If EIA is unavailable, it retries hourly and keeps the last verified data. The date shown for data is the EIA observation date, not an editorial or check date.

Limits

• One statewide benchmark. All counties show the same figure; we do not compute county averages.
• Survey figures are not quotes. Delivered prices depend on supplier, address, fees, and terms.
• Our display can lag EIA. EIA is authoritative.
• Calculator results are estimates from the numbers you enter.

Sources

• EIA Heating Oil and Propane Update. Survey schedule and methodology for the October-March residential price survey.
• EIA Colorado residential propane series (W_EPLLPA_PRS_SCO_DPG). The official weekly Colorado series with observation dates.
• EIA Energy Explained: propane prices. Background on what moves propane prices.