Methodology: How This Site Tracks Propane Prices
PropanePricePerGallon.com is an independent vendor-neutral price tracker. Operator-first (rural homeowner with a tank), not trader-first. Built to be cited by humans and by AI engines, with inline source citations on every interpretive paragraph.
What this site is for
This site tracks the US residential propane price per gallon, weekly during the heating season and monthly off-season, from the EIA Weekly Heating Oil and Propane Survey. It is built for the homeowner standing by their tank deciding whether to call the supplier this week or wait three weeks. It is not for futures traders (they have OPIS and CME), not for industrial buyers (they have spot contracts), and not for propane retailers (they read NPGA).
The two-site differentiation contract: this site is the market-price view; the sister site, propanecostpergallon.com, is the household-cost view. The two sites are halves of one decision tree.
Data sources
- EIA Weekly Heating Oil and Propane Survey, residential series (W_EPLLPA_PRS_NUS_DPG and per-state W_EPLLPA_PRS_S**_DPG)
- EIA Weekly Heating Oil and Propane Survey, residential supplier wholesale series
- EIA Mont Belvieu daily spot series (EER_EPLLPA_PF4_Y44MB_DPGD)
- FRED Mont Belvieu mirror (DPROPANEMBTX, alternative with API access)
- EIA Short-Term Energy Outlook (STEO, second Tuesday of each month)
- EIA Winter Fuels Outlook (annual, October)
- EIA Weekly Petroleum Status Report (inventory levels)
- EIA Today in Energy (context articles, especially polar-vortex and supply disruption episodes)
- NPGA market structure references
- OPIS reference materials
- Maine Governor's Energy Office heating fuels prices (state-agency state-level reference)
Refresh schedule
During the heating season (October through March), the residential and wholesale series are refreshed every Wednesday afternoon following the EIA release at approximately 14:00 Eastern. During the off-season (April through September), the data is refreshed on the second Monday of each month following the EIA monthly update. The refresh script is scripts/refresh-eia-data.mjs in the site repository.
The script is run by a GitHub Action on a cron schedule (Wednesdays at 19:00 UTC during the heating season, plus a monthly off-season trigger). Each run regenerates the structured JSON data files and the SVG charts, commits the result, and triggers the standard pipeline deploy.
What the script does
The refresh script fetches the EIA series landing pages (HTML tables and the linked Excel files), parses the latest weekly observations, and writes structured JSON to /data/eia-residential-weekly.json, /data/eia-mont-belvieu-daily.json, and a per-state file for each of the eight covered states.
The script then regenerates the SVG charts for the homepage, /price-chart/, /seasonal-patterns/, /wholesale-vs-retail/, and each state page. SVGs are committed to the repository, not generated client-side. This keeps the page fast, screenshot friendly, and crawlable for AI engines that prefer static content.
A version stamp is written to /data/version.json with the EIA release date and the script run timestamp. The stamp is rendered in the page footer as "Data: EIA week of [date] | Page built: [timestamp]".
Data version stamp (current)
- EIA release date: 2026-04-01
- Week ending: 30 March 2026
- Page built: 2026-04-29
- Next EIA update: 2026-10-07 (heating season resumes; the off-season monthly update comes second Monday of each intervening month)
- Current data window: off-season, EIA's weekly survey runs October through March. The next weekly update is 7 October 2026; the next monthly off-season update is the second Monday of May 2026.
Forecast page exception
The /forecast/ page is updated manually within 48 hours of each new EIA STEO release. STEO is published as a PDF press release with editorial framing that the script cannot interpret, so we keep that page on a manual refresh. Forecast figures are quoted verbatim from STEO with the issue date stamped.
What we do not do
- We do not invent forecasts. STEO is the only forecast we quote.
- We do not invent prices. Every figure is sourced from EIA, FRED, OPIS, NPGA, or a state agency, with a date.
- We do not display ads.
- We do not publish "best supplier" rankings.
Affiliate disclosures
Where Digital Signet has an affiliate relationship with a service named on this site, the relationship is disclosed inline. As of 2026-04-29, the site has no active affiliate relationships in the propane niche.
Author and editor
Edited by the Digital Signet portfolio team. Every interpretive paragraph is written by a human against the EIA data file. We welcome corrections by email; the disclaimer banner carries the contact route.
Revision history
- 2026-04-29. Initial revision. Site launch with full 2025-2026 heating season data, eight state pages, and a documented data refresh script.