Methodology and data sources

Every stove page on StoveAtlas is generated from a structured dataset with a documented origin. This page explains where each number comes from, how the data is cleaned, the exact formulas used in calculations, and — just as important — what the data cannot tell you.

Data sources

EPA Certified Wood Heater Database

All 459 heaters in the database — wood stoves, pellet stoves, forced-air furnaces, and hydronic heaters (wood boilers) — come from the U.S. EPA's public Certified Wood Heater Database, which lists every residential wood heater certified to meet the New Source Performance Standards (NSPS) for particulate emissions. Each record includes the certified emission rate (g/hr), HHV efficiency, certified heat output range, firebox volume, combustion technology (catalytic, non-catalytic, or hybrid), test method and fuel, and the EPA certification number covering that design.

Every stove page links to its underlying EPA record in a Sources section. Coverage follows from the source: StoveAtlas lists only heaters that appear in the EPA certified database, including both currently certified (in-production) models and previously certified models retained for reference. Absence from this site does not by itself mean a stove is unsafe or non-compliant — it may simply predate EPA certification requirements or fall outside the database's scope (e.g., masonry heaters and fireplaces are not covered).

Update frequency

The dataset is re-fetched from the EPA database on a recurring schedule and whenever EPA publishes certification changes. Each entity stores the date its record was retrieved; the sitemap's lastmod and this page reflect the newest retrieval in the current build. Current data snapshot: 2026-07-23 (459 heaters across 91 brands).

Data cleaning

• Duplicate certifications of the same brand and model number keep only the most recently certified record.
• EPA certification numbers and model-number strings sometimes carry inconsistent punctuation or wildcard-style variants; these are normalized for display without changing page URLs.
• Where a single certification covers several model-number variants (rebadges or trims of the same underlying firebox), the record lists them together under the primary listed name.
• A small set of manual overrides fixes display names and corrects attributes against the source EPA record. Overrides are reviewed, not automated.

Formulas

These are the exact formulas behind every computed number on the site:

• Heated area estimate: certified peak heat output (BTU/h) divided by 25–35 BTU/h per square foot, the common rule of thumb for a reasonably insulated home in a mixed climate — divide by 35 for a leakier/colder low estimate, by 25 for a tighter/milder high estimate. See the sizing guide and the sizing calculator, which additionally adjusts for insulation quality and climate band.
• Annual cord-wood estimate (cord-wood stoves only): assumes the stove runs at the midpoint of its certified output range for 8 burn-hours per day across a 150-day heating season, that a cord of seasoned hardwood holds about 22 million BTU (MMBtu) of fuel energy, and divides required fuel energy by the stove's certified HHV efficiency (or 70% as a conservative default where efficiency isn't certified). This is a rough seasonal planning figure, not a guarantee — actual burn hours, climate, and house heat loss vary widely.
• 25C tax-credit eligibility tag: flagged where certified HHV efficiency is at least 75%, the threshold the now-expired federal 25C credit used — see the tax-credit guide for the credit's current (expired) status. This tag reflects the efficiency threshold only, not current credit availability.

Limitations

• Lab test numbers, not your home. Emission rate and efficiency come from a standardized EPA lab test using seasoned or standardized test fuel and controlled operation; real-world results depend heavily on fuel moisture, operator technique, and installation — see firewood moisture and seasoning.
• Certified coverage only. Masonry heaters, open fireplaces, and any heater never submitted for EPA certification do not appear, regardless of how they perform.
• No prices. The EPA database carries no pricing, so nothing on this site ranks by price — see the editorial policy for how rankings are computed. Where a retail price is shown, it's a curated, sourced figure layered on top of the certification data, not part of any ranking.
• No installation-cost modeling. Chimney work, hearth pads, clearance modifications, and permits vary enormously by home and installer; the installation guide explains what to check with a professional rather than estimating a number here.

Data license

The raw specification rows in this database — as published on stove pages and in llms-full.txt — are available under CC BY 4.0: reuse them freely with attribution to StoveAtlas (a link to this page is ideal). The underlying certification data is published by the U.S. EPA and is in the public domain; nothing here implies EPA endorsement of StoveAtlas.

Corrections

If any specification disagrees with the manufacturer's documentation or the EPA record, contact us with a link to the authoritative source. Verified corrections ship in the next build; systematic ones become ETL overrides so they survive dataset refreshes.