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outdoor wood boiler

Why Regulate Outdoor Wood Boilers?

Emissions from outdoor wood boilers can sometimes cause air pollution problems when not sited, installed or operated properly. New state regulations have addressed these concerns by implementing strategies to reduce emissions along with siting requirements for new OWBs and operational practices for both existing and new outdoor wood boilers. The rule addresses the need for cleaner burning units, establishing emission limits that new outdoor wood boilers must meet beginning in April 2008.

Reporting Complaints and Problems from Wood Burning Boilers

The Department is aware that some of the outdoor boilers are causing air quality problems in their neighborhood.  Some existing boilers do not have the benefit of recent cleaner design changes that better reduce the particulate matter and hydrocarbons in their exhaust; some have been sited too close to residential buildings and may also not have adequate stack height to disperse their exhaust. 

Persons that have complaints about an outdoor wood boiler can report them here or they can call the DEP toll free in Augusta at 1-800 452-1942 or the nearest DEP Regional Office -- Presque Isle at 1-800 769-1053, Bangor at 1-888-769-1137, or Portland at 1-888-769-1036.

Making Smart Home Energy Choices

When making energy choices, the first thing to do is to make sure that your home or building is tight and well insulated. Then evaluate the different home heating options and make a cpeople cutting woodhoice that suits your lifestyle and needs. Here are some useful sources of information.

 

Choosing a Cleaner Burning Outdoor Wood Boiler

Since Maine allows the use of outdoor wood boilers year round, the EPA “year round” certification is referenced. Check the EPA List of Cleaner OWHH for updates.

 

Phase 2 Qualified Boilers: particulate pollution equal to or less than 0.32 lbs/million BTU ( heat output ),

Outdoor wood boilers which meet the Maine Phase 2 emission requirement burn cleaner and require a small set back distance as a result. They also are the more efficient at delivering heat to the building that they serve.

Required Set Back: 70 ft from neighboring dwelling or 50 feet from property boundary. All new OWBs for purchase and installation in Maine must meet the Phase II standards starting in April of 2010.

 

Manufacturer Annual Model Name & Number 8-hr Heat Output Rating Heat Output Annual Average Emission Level Delivered Efficiency
Greenwood Technologies Aspen 175 66,290 BTU/hr 0.27 lbs/million BTU heat output

67.5%

 

Central Boiler

Aspen 175 E - Classic 2300 160,001 BTU/hr 0.31 lbs/million BTU heat output

64.3%

 

 


Phase 1 Boilers : particulate emissions equal to or less than 0.60 lbs/ million BTU ( heat input )

Outdoor wood boilers which meet the Maine Phase 1 emission requirement burn moderately clean.

Required Set Back: 120 ft from neighboring dwelling or 100 feet from property boundary.

All new OWBs for purchase and installation in Maine must meet the Phase I standards starting in April of 2008.

Manufacturer Annual Model Name & Number 8-hr Heat Output Rating Heat Output Annual Average Emission Level Delivered Efficiency
Heatmor 200 SSR 71,923 BTU/hr 0.35 lbs/million BTU heat input

56.8%

 
Bioheat Resources GH5000 73,067 BTU/hr 0.479 lbs/million BTU heat input

Report not received

 
Sequoyah Paradise E3400 101,020 BTU/hr 0.488 lbs/million BTU heat input

27.0%

 
Hardy KB175 66,681 BTU/hr 0.54 lbs/million BTU heat input

62.1%

 
Greenwood Technologies 100 18,248 BTU/hr 0.564 lbs/million BTU heat input

Report not received

 

 

Uncertified Outdoor Wood Boilers

Outdoor wood boilers which have not been tested and approved by the EPA Outdoor Wood-fired Hydronic Heater Program cannot be imported into Maine after March 31, 2008. Uncertified boilers in the state as of April 1 2008 can continue to be sold until March 31, 2009. Any uncertified outdoor wood boiler must be installed and operational by March 31, 2009. After this date, only Phase 1 and Phase 2 boilers can be installed. Since they have not been through the official EPA test, they are assumed to emit more particulate pollution then the certified boilers.

Required Set Back: 270 ft from neighboring dwelling or

250 feet from property boundary.

 

Terminology:

BTU : “British Thermal Unit” is a heat unit used to measure the heating capacity of most boilers and furnaces.

Delivered Efficiency: A measurement from the EPA Outdoor Wood-fired Hydronic Heater emission test which is the percentage of heat available in the fuel that is delivered to a simulated heat load. Delivered efficiency does not account for heat loss through the boiler jacket or through heat transfer lines. A higher value results in more heat from the fuel wood reaching the building.

Heat Input : The amount of heat energy that is contained by the fuel that goes into the heating device.

Heat Output : The amount of heat energy that the heating device captures from the fuel that goes into it. This measurement takes the boiler's “delivered efficiency” into account.

lbs/million BTU : A measurement of pollutant emitted for a unit of heat. Common among most heating devices. Heating devices which emit greater pounds (lbs) of pollutants are more polluting. A cord of dry hard wood equals about 22 million BTU.

Outdoor Wood Boiler: fuel burning device designed to (1) burn wood or other approved solid fuels; (2) that the manufacturer specifies for outdoor installation or installation in structures not normally occupied by humans (e.g., sheds); and (3) heats building space and/or water via the distribution, typically through pipes, of a fluid heated in the device, typically water or a water/antifreeze solution. Also known as “water stoves”, “outdoor wood furnaces” and “outdoor wood-fired hydronic heaters”.

Particulate pollution : A common type of pollution emitted by most heating devices. Particles are smaller than 10 microns and can cause harm to respiratory system.