IMPORTANT - MY OPINION Only

Generally Speaking, Federal EPA Law dictates that boilers are for COMMERCIAL heating only.

We have often heard that the state law takes precedence over the federal one, according to https://www.wolterskluwer.com/en/expert-insights/us-federal-vs-state-environmental-regulations-what-to-follow

If a state law gives people more rights than a federal law, the state law is legally supposed to prevail. The Constitution is a different realm altogether; due to the Supremacy Clause of the Constitution

There are two basic levels in the U.S legal system: federal law and state law. A federal law applies to the nation as a whole and to all 50 states whereas state laws are only in effect within that particular state.

State vs. EPA Enforcement. In terms of implementation and enforcement, the EPA generally will defer to a state. But because the EPA retains concurrent enforcement authority, there are specific situations where the EPA may choose to act. https://www.wolterskluwer.com/en/expert-insights/us-federal-vs-state-environmental-regulations-what-to-follow

Several states such as Missouri, Hawaii, and Michigan have chosen to ignore the EPA's regulations altogether.

MICHIGAN: Current through Public Act 61 of the 2022 Legislative Session

Section 324.5514 - Department of environmental quality; prohibited acts; "wood heater" defined

(1) The department of environmental quality shall not do any of the following:

(a) Promulgate a rule limiting emissions from wood heaters.

(b) Enforce against a manufacturer, distributor, or consumer a federal regulation limiting emissions from wood heaters and adopted after May 1, 2014.

Many others states appear to have no information available online, such as Alabama, Connecticut, Florida, Illinois, Indiana, Iowa, Louisiana, North Carolina, Ohio, Oklahoma, West Virginia and others.

Pennsylvania said in the past a coal boiler was fine (because they produce so much coal) and their regulations have not been updated since 2011

Tennessee appears to have no regulations for wood heaters.

Boilers are exempt from Wisconsin's wood heating regulations (NR 440.642), and the state is currently trying to pass a bill (2015 Assembly Bill 25) that will prohibit the EPA's new regulations for all wood heaters!

So you can see that states CAN make their own determination and laws.

To see Wood Boiler Regulations By State, Please visit https://woodstoves.net/blog/wood-boiler-regulations-faq.htm

It seems to me that the state is the enforcer, so it is ultimately up to YOU, the consumer to check with YOUR local Department of Environmental Quality to see what regulations apply to you.

I see that Washington State and New York are definitely a no-go

Some states make exceptions to EPA certification if you don't have access to other heating options. These exceptions are too numerous to list here, but please contact your state's environmental department for more information.

See this page about NY: https://www.nysenate.gov/legislation/bills/2019/s6599