Corn Stoves
Corn stoves gained a lot of popularity up until about 2012, when corn prices rose due to US policy that heavily subsidizes ethanol. Mike Tidwell, a climate change activist in Takoma Park Maryland, where the Alliance for Green Heat is based, started a corn heating coop in 2008 as a way to wean homes off of gas and oil.
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Corn has many advantages, but unless it is very cheap, the disadvantages outweigh the advantages. On the positive side: corn only takes 4 months to grow, it doesn’t need to be processed other than getting it off the cob and dried, its plentiful and its locally available. During Great Depression, corn became a popular heating fuel, particularly in the Midwest, when corn was nearly worthless.
However, corn contains sugars which can clog burn pots and the smoke is far more corrosive than pellets, requiring special vent pipe. It is not a good idea to burn corn in a pellet stove, and can void the warranty, unless the stove is designed specifically to handle corn. This page offers good advice on corn stoves. Stoves advertised as “multi-fuel” stoves usually refer to corn and pellets but also can burn cherry pits and a number of other fuels.
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We believe corn could be an excellent low-carbon heating fuel since most corn for domestic use now is either used to make ethanol, feed cows or make sucrose. The only substantial use of corn to feed humans is what we export. Heating with corn is a far more efficient use of the crop than ethanol, which involves considerable refining.
EPA certification: Corn stoves are not covered by EPA emissions regulations and do not need to be certified unless they also advertise that they burn wood pellets. We know of at least two certified pellet stoves that are also designed to burn corn: US Stove model 6041 and the Regency GC60 pellet stove. Unfortunately, the EPA does not designate stoves that are able to burn corn, even though the EPA stove database lists corn as one possible fuel.
The EPA also does little to educate consumers about corn stoves and how they rarely are tested for emissions and efficiency and could rate poorly on both accounts. Curiously, the EPA website poses the question “Do they burn cleaner than wood stoves?” but makes no attempt to answer it other than to state: “Their operation and effectiveness is similar to that of pellet stoves” which glosses over many important distinctions consumers should be aware of
Many corn stoves improperly list pellets as a fuel option, ignoring the EPA requirement that you must test and certify if your appliance advertises that it can use wood pellets. The uncertified Country Flame Harvester Multi-Fuel stove seems to thread the needle properly, by advertising corn and a “variety of flex-fuels” without mentioning the word “pellet” which would trigger a requirement to certify the stove.
A number of states require EPA certification for wood and pellet stoves to be installed (such as Colorado, Oregon, Washington and Vermont) but corn stoves may be allowed as those regulations may only stipulate wood and pellet stoves and boilers. Check your state or local jurisdiction first. Also check to make sure a corn stove is safety listed by UL or something similar. Most or all are safety listed, as far as we know.
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Eligibility for the IRS tax credit: To be eligible for the IRS tax credit, biomass heaters must have a minimum of 75% HHV efficiency. Neither the US Stove or Regency certified pellet stoves designed to also burn corn are close 75%. Congress did not say the heater had to be EPA certified but many believe that is implied. Consumers may rely on a manufacturer certificate stating the appliance is at least 75% HHV efficiency. If a corn stove has not gone through certification, it is doubtful that they have any accurate third-party efficiency testing and are likely not to be eligible. Ask the manufacturer if they can give you a certificate and how they tested for efficiency. Some corn stove manufacturers make wildly exaggerated claims about their efficiency.
Corn stove manufacturers: The number of companies making corn stoves has shrunk. Amaizablaze makes a line of uncertified corn stoves. Woodstoved.pro lists five stoves that can burn corn. Pel Pro has discontinued their corn stove model and Bixby stoves went out of business.
Background: The Province of Ontario has an in-depth web page that is positive about heating with corn. Daniel Ciolkosz at the Penn State extension also provides valuable information about heating with corn. This promotional corn stove site has a wealth of information as of 2007, and is a good snapshot of that point in time when corn heating was cheaper and growing in popularity.