Outdoor Wood-Fired Boilers

Outdoor Wood-Fired Boilers (OWBs), also known as Hydronic Heaters, are large sheds used to heat water by burning wood. The heated water is then piped to a nearby house or commercial structure where it provides ambient heat or it is used as the hot water supply.

OWBs can generate a significant amount of fine particulate pollution. Because of this, the Pennsylvania Department of Environmental Protection regulates the use of OWBs.

In addition to the state regulations, the Allegheny County Health Department has implemented an OWB regulation of their own that limits the use and installation of OWBs throughout Allegheny County.

The requirements mandated by Article XXI, §2104.09, “Outdoor Wood-Fired Boilers”(PDF, 43KB) include:

  • Only Phase-II qualified OWBs may be installed. See: EPA's list of Phase-II qualified OWBs.
  • Phase-II OWBs must be installed 150 feet from the nearest property line.
  • OWBs must have an attached stack which extends a minimum of 10 feet above the ground and at least two feet above the peak of the highest residence located within 150 feet of the OWB.
  • OWBs may not be used on an Air Quality Action Day, when air pollution levels are expected to be higher than safe levels. Air Quality Action Days are announced on most local weather forecasts. Individuals can sign up to receive the air quality forecast, including notifications about Air Quality Action Days.
  • At the time of sale or lease of a property with an OWB, buyers or lessees must be given a copy of the regulation and the seller or lessor must provide a record of the sale or lease, including the address where the OWB is located, to the ACHD.

View the Outdoor Wood-Fired Boiler Written Notice and Recordkeeping Form(PDF, 76KB).

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