All wood stoves certified under the 2015 New Source Performance Standards (NSPS) have been independently tested by an accredited laboratory to meet a particulate emissions limit of no more than 4.5 grams per hour.  Many room heaters certified under the 1988 NSPS also meet this emission limit and will be included in a database of appliances maintained by the EPA Office of Enforcement and Compliance Assurance (OECA).

In 2020, the NSPS emission limit for new room heaters was lowered to 2.0 grams per hour if tested with crib wood*, or 2.5 grams per hour if tested with cord wood*. 

All new wood heating appliances subject to the New Source Performance Standard for New Residential Wood Heaters under the Clean Air Act offered for sale in the United States are required to meet these emission limits.

The Office of Enforcement and Compliance Assistance certifies all wood heaters subject to the 2015 New Source Performance Standards for Wood Heaters and maintains lists of all appliances here:  List of EPA-certified wood heaters.

* Crib wood is cut 2”x4” or 4”x4” lumber that is stapled together.  Cord wood is typical firewood which is a better measure of how a heater will perform in homes.