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Information about outdoor furnaces, emissions standards, and industry terms.Outdoor Wood Furnace Chimney Emissions Standards and the Environment

 
Americans have burned wood as a primary source of heat for generations. Responsible manufactures, like Central Boiler, work to ensure their furnaces (also referred to as hydronic heaters) are properly installed and used to produce clean, safe and efficient heat. 
 
EPA Emissions Testings
To understand the environmental impact of a Central Boiler outdoor wood burning furnace, it is best to rely on the testing and reports generated by the U.S. Environmental Protection Agency (EPA). After testing a Central Boiler outdoor wood burning furnace, EPA reported that these furnaces produce similar particulate matter (PM) as wood stoves.
 
EPA said: “Compared to a wide range of residential heating options, these furnaces’ emissions were of the same order as other stick wood burning appliances.” (EPA report: EPA/600/SR-98/017, February 1998)
 
Furthermore, when comparing data from this report and data from a report on EPA certified phase 2 indoor wood stoves (EPA report: EPA/600/SR-00/100 December 2000), the comparison shows emissions from the Central Boiler wood furnace and EPA certified phase 2 indoor wood stoves both average 10 grams of particulate matter per kilogram (g/kg) of wood consumed. (Emissions Comparison from Two EPA Reports)
 
When heating a home, outdoor wood furnaces also produce less particulate matter than fireplaces.
 
EPA Emissions Guidelines
Central Boiler has worked closely with EPA on new testing standards and works with state and local governments on appropriate regulations to encourage cleaner burning outdoor wood furnaces and to implement Best Burn Practices.
 
On January 29, 2007, EPA announced new emissions test guidelines under Phase 1 to promote the manufacture and sale of cleaner outdoor wood furnaces. Phase 1 ended on March 31, 2010.
 
On October 23, 2008, EPA announced Phase 2 of EPA’s Hydronic Heater Program to promote the manufacture and sale of cleaner and more efficient outdoor wood furnaces.
 
In addition, Central Boiler has developed the new E-Classic 2300, E-Classic 1400, E-Classic 2400, E-Classic 3200 and the Maxim M250 next-generation outdoor furnaces that are EPA HH Phase 2 Program Qualified. The EPA HH Phase 2 Program for outdoor wood furnaces has an even more stringent emission standard of 0.32 lbs/million Btu of heat output. In order to meet an output based emission limit, the appliance must achieve low PM emissions and high efficiency. Basically, the Phase 2 Program has built in into it, requirements by manufacturers to produce appliances that are capable of producing low emission along with high efficiency.
 

Central Boiler's Phase 2 Qualified White Tag Models

Manufacturer Model Name & Number Heat Output Rating (1) Annual
Average
Emission
Rate
Heat
Output

Annual
Average Emission
Level
(2)
Highest Individual
Test Run
Fuel Type
Central Boiler
Maxim
M250
212,453 BTU/hr

1.6
grams/hr

0.07 grams/hr/ 10,000 BTU
heat output

0.06
lbs/million BTU output

4.9
grams/hr
wood pellets; continuous feed
Central Boiler
E-Classic
3200
261,506 BTU/hr

3.3
grams/hr

0.02 grams/hr/ 10,000 BTU
heat output

0.08
lbs/million BTU output

7.3
grams/hr
stick wood;
batch load
Central Boiler
E-Classic
2400
186,453 BTU/hr

3.3
grams/hr

0.03 grams/hr/ 10,000 BTU
heat output

0.12
lbs/million BTU output

5.4
grams/hr
stick wood;
batch load
Central Boiler
E-Classic
1400
107,459 BTU/hr

5.5
grams/hr

0.08 grams/hr/ 10,000 BTU
heat output

0.27
lbs/million BTU output

8.5
grams/hr
stick wood; batch load
Central Boiler
E-Classic
2300
160,001 BTU/hr

6.4
grams/hr

0.06 grams/hr/ 10,000 BTU
heat output

0.31
lbs/million BTU output

17.6
grams/hr
stick wood; batch load

1 - Based on 8-hour test for stick wood models and 4-hour test for continuous feed models.
2 - EPA Phase 2 qualified level is 0.32 pounds of fine particles per million BTU of heat output (weighted average representing the range of burn rates expected in a year) and a maximum individual test run of 18.0 grams per hour. Typically, the maximum individual test run is the maximum heat output burn rate.

 
Other Emissions Studies
Some emissions studies report that heating homes with outdoor wood furnaces produce more emissions than heating homes with indoor wood stoves. These reports are misleading. In order to heat a typical 3,000-square-foot home, the number of wood stoves required to heat the home would have comparable emissions to those from a single outdoor wood furnace heating that same home.
 
In fact, outdoor wood furnaces are more efficient than fireplaces. There are more than 16 million fireplaces used in homes in the United States. A Central Boiler outdoor wood furnace will heat a home with less wood burned and far fewer PM emissions than heating the same home with fireplaces.
 
Reportedly, there are about 200,000 outdoor wood furnaces and 10 million indoor wood stoves in the United States. 



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