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Particulate Emissions Results from 

Burning Shelled Corn in Pellet-Fired 

Room Heaters 

Report Date: March 6, 2008

OMNI-Test Laboratories, Inc. 

Product Testing & Certification 

Mailing: Post Office Box 743 Phone: (503) 643-3788 

Street: 5465 SW Western Avenue Suite G Fax: (503) 643-3799 

 Beaverton, Oregon 97075 USA
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Particulate Emissions Results from Burning 

Shelled Corn in Pellet-Fired Room Heaters and 

Multi-Fuel Fired Room Heaters 

With the exploding popularity of pellet-fired appliances in the last 3 years, burning 

different types of bio-mass has also increased. This may have gained media attention 

when the National Energy Bill was introduced and the term “switch grass” became 

popular. With recent media coverage of bio-mass fuels and the need for clean burning 

renewable energy, burning corn is becoming more popular throughout the United States 

and Canada. Shelled corn traditionally has been used for farm animal feed, but this 

same product can be used for heating purposes. This product is readily available at 

most feed stores in 40 or 50 lbs. sacks. 

Wood pellet-fired appliances are tested using EPA Method 28 fueling protocol. This 

method only specifies using “wood” pellets. It has been known that pellet-fired heaters 

traditionally are clean-burning appliances. It is not unusual to have a weighted average 

of a pellet-fired appliance in the range of 1-3 grams/hr. 

There have been a number of studies reviewing the air emissions from pellet stoves. In 

the year 2000, Dr. James Houck in conjunction with others, wrote a paper titled “Low 

Emission and High Efficiency Residential Pellet-Fired Heaters”. This paper reviewed a 

number of these studies. His key conclusions by reviewing the pellet stove emission 

data are: 

New-technology pellet stoves produce much less CO than uncertified cordwood 

stoves. 

New-technology pellet stoves produce much less PM than uncertified cordwood 

stoves. 

The emission factors for both CO and PM are lower for new-model pellet stoves 

than for earlier models. 

Not all PM emitted from pellet stoves are PM10 or PM2.5. Approximately 84% of 

PM is PM10 and about 81% is PM2.5. PM10 and PM2.5 emission factors, if based 

on total PM measurements, should be adjusted accordingly. 
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The chemical makeup of PM emitted from top-feed pellet stoves and under-feed 

pellet stoves is different, and the chemical makeup of PM from both technology 

types is different from that emitted from cordwood stoves. Consequently, total 

PM emissions are not accurate surrogates for emissions of specific organic 

compounds such as those identified as “air toxics.” 

Pellet stoves generate less solid waste than cordwood stoves. 

The high efficiencies and low emissions of PM and CO characteristic of newtechnology pellet stoves, combined with low greenhouse gas impacts, low acid 

precipitation impacts, and minimal solid waste issues, make pellet stoves an 

environmentally sound home space heating option. 

With the increasing trend toward burning bio-mass other than wood pellets, 

manufacturers are designing or re-designing their products to accommodate corn, 

switch grass, wheat, barley, sunflower seeds and even cherry pits. Also, new fuels are 

being designed from agricultural and silvacultural by-products. Since emissions are a 

critically important performance parameter and corn is currently the most popular and 

readily available non-wood biomass fuel, pellet stove manufacturers have undertaken a 

survey study and analysis of existing corn-burning emissions data. The objective of this 

study was to establish a good statistical comparison with wood-pellet emissions. To 

accomplish this goal, all of the pellet stove manufacturers were asked to submit any and 

all corn-burning emissions results they have collected for compilation and statistical 

analyses. 

Because EPA Method 28 does not specify the use of any other bio-mass fuels, EPA 

certification of appliances using other bio-mass fuels is not accommodated at this time. 

Hearth Products and Barbeque Association (HPBA) contracted OMNI-Test 

Laboratories, Inc (OMNI) to compile emission results from heating products capable of 

burning shelled corn. The members of the HPBA Corn Caucus were requested to 

submit emissions data to OMNI for review and to report the results. OMNI received 5 

data points from 5 different manufacturers of corn-burning appliances. All five of these 

data points where from room heaters. The results are blinded for reporting at the 

request of the manufacturers.

Each of the data-contributing manufacturers submitted data for only one test run each. 

Except for using the corn fuel, all the reported tests were performed using the Method 

28 fueling protocol and the Method 5G emissions sampling system. As required for all 

EPA certification tests, all results were converted to Method 5H equivalents. As 
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presented in the table below, the particulate emissions ranged from the room heater 

appliance from 1.37 g/hr on the low end to 4.84 g/hr on the high end. 

Appliance Type 

Burn 

Rate 

(kg/hr) 

Emission 

Rate 

(g/hr) 

Moisture 

content 

(DB) 

g/MJ 

Emission 

Factor 

(g/kg) 

Stove A 1.0 4.8 9% 0.41 4.8 

Stove B 1.6 3.1 14% 0.17 1.93 

Stove C 1.2 2.8 11% 0.20 2.33 

Stove D 1.0 1.4 9% 0.12 1.40 

Stove E 1.1 1.7 9% 0.13 1.54 

Average 1.18 2.76 10% 0.20 2.40 

Conclusion: 

The results complied from the 5 data points suggest that corn is a clean burning fuel 

although in some cases not as clean as wood pellets. 

It should be noted that the compiled results do indicate that if EPA’s Method 28 was 

changed to allow corn to be used as a test fuel, all the appliances would pass EPA’s 

7.5 g/hour woodstove standard.