Wood Heater Compliance Monitoring Program

On this page:

• Compliance Monitoring News and Updates
• Wood Heater Certification Test Report Deficiency Letter Issuance Update
• Certificate of Compliance Renewal Policy
• EPA Contact

Residential wood heaters, which include wood and pellet stoves, hydronic heaters and forced-air furnaces, can contribute significantly to particulate air pollution which may pose serious health concerns.  In 2015, EPA strengthened the clean air standards for residential wood heaters to make heaters significantly cleaner and improve air quality in communities where people burn wood for heat.

Residential wood heaters must comply with the applicable emission standards and other requirements of the 2015 Rule in order to be EPA-certified.  Manufacturers must participate in a certification program and have their wood heaters undergo certification testing at an EPA accredited laboratory to verify their heaters meet the required emission standards.  Thereafter, manufacturers may obtain an EPA Certificate of Compliance for each of their wood heaters to enable the manufacturer to manufacture, offer for sale, advertise, or import a wood heater into the United States.

To help consumers buy EPA-certified wood heaters, check out the EPA Certified Wood Heater Database.

Compliance Monitoring News and Updates

June 2, 2022 – EPA is committed to ensuring all wood stoves and other wood-burning device manufacturers, laboratories, States, and the public are aware of potential certification testing deficiencies in new and existing Certificate of Compliance applications. EPA has posted a list of all deficiencies that could result in a revocation of existing certificates or new application denials in order to assist manufacturers and laboratories and expedite their efforts to address any certification testing deficiencies.

Further, EPA has identified a number of categories where manufacturers will be required to re-test existing model lines upon renewal. EPA will continue to provide in-depth reviews of incoming renewal applications and may change these categories in the future.

April 5, 2021 -- EPA is committed to ensuring that new wood stoves and other wood-burning devices comply with Clean Air Act standards to reduce health-harming pollution.  In light of information from states and other stakeholders provided in late 2020 and early 2021, the agency is taking a number of actions to address concerns about the methods and manner in which new wood stoves are being tested for compliance with the 2015 New Source Performance Standards under the Clean Air Act.

These actions will take time and continued engagement with stakeholders. Given the concerns raised, EPA is carefully reviewing both current and new Certifications of Compliance and will take steps as appropriate.  More information is available at  EPA-Approved Test Labs and Third-Party Certifiers for Residential Wood Heaters.

Wood Heater Certification Test Report Deficiency Letter Issuance Update

As part of the wood heater certification test report review process, EPA is working to address deficiencies identified in how certification testing was conducted and/or in the documentation of certification testing. As of May 1, 2022, EPA has issued 57 minor deficiency letters, 1 moderate deficiency letter, and 12 major deficiency letters to wood heater manufacturers.

Major, moderate, or minor deficiencies are identified problems or irregularities that are or could result in a determination that the certification test is invalid. The agency’s determination that such a certification test is invalid may serve as a basis for revoking a Certificate of Compliance regardless of the deficiency category.

1. Major deficiency letters concern problems or irregularities with the certification test that could potentially affect emissions and therefore pose a risk to human health and/or the environment if the certification were to be maintained. Upon receipt of a major deficiency letter and prior to the agency initiating the revocation of the Certificate of Compliance, the manufacturer may choose to stop sales, re-test, and submit a valid certification test report documenting compliance with the emission standard. If the manufacturer chooses not to stop sales, chooses not to re-test, or if the re-test is determined to be invalid or fails to meet the emission standard, EPA will proceed with the revocation of the Certificate of Compliance in accordance with the Wood Heater Rule. Information on wood heater model lines currently or recently subject to the revocation process can be found at Filings, Procedures, Orders and Decisions of EPA's Administrative Law Judges by using the case information in the Wood Heater Model Line Certificate of Compliance Revocations Proceedings chart to search the e-docket database.

2. Moderate deficiency letters concern regulatory and/or test method problems or irregularities that occurred during the certification test but likely do not affect emissions or create an unlevel playing field between manufacturers. However, the irregularities are inconsistent with the requirements of the Wood Heater Rule or test method(s) used. Therefore, manufacturers are required to re-test prior to renewal of their Certificate of Compliance and will not be granted a waiver to re-testing upon renewal. This applies to the re-review of existing certifications that are not yet due for renewal; new applications and renewals will be required to re-test prior to processing the request.
3. Minor deficiency letters generally concern problems or irregularities with the documentation of the certification test report, which may be addressed by the manufacturer submitting a revised certification test report. That submission is required to provide either clarifying or additional information to confirm the certification test was completed in accordance with the Wood Heater Rule and applicable test method. However, it is important to note that if the information obtained from the manufacturer uncovers potential emission-related issues, this determination could be upgraded to either moderate or major deficiency.

• EPA Wood Heater Appliance Test Report Deficiency Items: Major, Moderate, And Minor Irregularities (pdf) (381.33 KB)

Certificate of Compliance Renewal Policy

Submission Timing

1. To receive a timely renewal of a Certificate of Compliance, a manufacturer should submit a complete application no later than 90 calendar days before the Certificate is set to expire to allow for sufficient time for EPA to process the renewal request.

2. Renewal requests submitted less than 90 days before the Certificate of Compliance expires will be processed as quickly as resources allow. However, they may not be processed before expiration despite the agency’s best efforts. In this case, the manufacturer must halt sales after the Certificate’s expiration. Sales after expiration and prior to renewal are prohibited pursuant to 40 CFR §§ 60.538(c)(1) and 60.5480(c)(1).

Denial of Waivers of Retesting (40 CFR § 60.533(g))

EPA expects that it will deny a manufacturer’s request for Certificate of Compliance  renewal without a new valid certification test if one of the below conditions are met: 

1. Manufacturers who submit a renewal application after the Certificate of Compliance has expired should not expect to be granted a waiver from certification testing. Manufacturers should expect to re-test and submit a new application for a certificate in those circumstances.
2. Given potential impacts on human health and the environment, EPA expects to deny waivers from certification testing for the following wood heaters:
   1. Wood Heater and Central Heater model lines where a “moderate” deficiency is identified in a letter issued by EPA.
   2. Certification test reports at or above the following emissions values:
      1. Wood Heaters (pellet or crib wood fuel) - 1.9 g/hr
      2. Hydronic Heaters (pellet or crib wood fuel) - 0.09 lb/mmBTU
      3. Hydronic Heaters (cordwood fuel) – 0.14 lb/mmBTU
      4. Forced-Air Furnaces – (cordwood fuel) – 0.14 lb/mmBTU
   3. Wood heaters originally tested under ASTM 3053 test method. Further, the re-test must be conducted under an EPA-approved test method at renewal consistent with EPA’s notice for withdrawal of ALT125/ALT127 test methods.

EPA is constantly evaluating the criteria above for future modifications.

The EPA reserves the right to change, modify, or act at variance with the above without notice.

Please note: Any request for a model name change or model name addition to the Certificate of Compliance may not require re-testing.

​EPA Contact  

For questions, please contact: Wood Heater Reports (WoodHeaterReports@epa.gov)