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New Wood Heater & Boiler Regulations (Act 50)

July 8, 2019

On June 10, 2019, Governor Scott signed into law Act 50 which establishes milestones for the regulation and oversight of certain Industrial, Commercial and Institutional (ICI) wood heaters (a.k.a. boilers) in the State of Vermont.

Through this session law the Legislature has charged the Air Quality & Climate Division (AQCD) with amending the state’s air pollution regulations that apply to ICI wood boilers using cordwood, wood pellets or wood chips as fuel.  These changes will include rules that allow for methods, other than EPA certification, of demonstrating compliance with the applicable air quality rules and standards.  An example of another method is to use the test results from the European test method “EN 303-5”.

Milestones for changing the rules:  by July 1, 2019, the AQCD must submit a copy of the draft rule amendments to the Air Pollution Control Regulations to the Senate Committee on Natural Resources and Energy, as well as the House Committees on Energy and Technology and on Natural Resources, Fish and Wildlife.  Further the AQCD must commence the formal rule making process by October 1, 2019 and adopt the rule changes by May 1, 2020. 

While the air quality regulations are being amended, the legislature has allowed for other provisions, discussed below, to be put in place to allow the sale and installation of certain ICI wood boilers.

Between June 10, 2019 and September 1, 2019, any new ICI wood boilers, with a heat input less than 6.5 MMBtu/hr and equipped with an oxygen trim system[1]  may be sold and installed in Vermont without requiring additional approval from the AQCD.  Note that wood boilers larger than 6.5 MMBtu/hr heat input have been and continue to be required to obtain a construction permit issued by the AQCD before the boiler is installed.

The AQCD has developed a certification process and application to review performance data for individual models of ICI wood boilers based on alternative testing methods, such as EN 303-5.  For a unit to be certified for sale and installation in Vermont, the review must determine that the wood boiler model meets the applicable EPA emission standards.  Existing units certified by the U.S. EPA for the type of wood fuel the unit is proposed to burn (e.g. pellets or chips), do not need to be certified by Vermont.  Manufacturers or installers (on behalf of the manufacturers) may submit an Application for Certification of Industrial, Commercial or Institutional Wood Heater for each specific wood boiler model that they are seeking to have certified by Vermont through this interim process.  After September 1, 2019, ICI wood boilers will only be allowed to be sold or installed in Vermont if they are certified pursuant to the process prescribed by the AQCD.

For more information, please visit our New Wood Heater & Boiler Regulation Page.


[1] “Oxygen trim system means a system of monitors, including an oxygen sensor, that is used to automatically maintain excess air at the desired level in a combustion device over its operating load range.”