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Corn Stove Buying Guide – Burn Corn To Heat Your Home
Burning corn is one of the best ways to heat your home. It’s cheaper than fossil fuels, it’s good for the environment, and it allows you to cut the cord from utility companies. We put together this ultimate guide that will teach you everything you need to know (and more) about corn stoves and corn as a fuel.
Is It Right For Me?
Advantages
- Cost effective. Burning corn is an extremely cheap way to heat your home, especially when fuel prices are high. It has a very high energy output for its size and weight. Check our fuel comparison chart to calculate the differences in price.
- Readily available. If you live in the Midwest, you should have no problem finding shelled corn to buy. The US has 80 million acres of land exclusively dedicated to corn cultivation. 300,000 of the 316,000 corn farms (95%) are family owned. Many corn stove users make arrangements with privately owned farms to acquire their corn at a cheaper price.
- Automated. Corn stoves are (for the most part) automated in their operation and some can even be controlled with a thermostat. It’s a reliable way to burn corn 24/7.
- Easy to handle. Unlike wood, corn is much easier to handle and is significantly less work. There’s no cutting, splitting, or stacking. Simply pour it into the hopper and you’re done.
- Environmentally friendly. Corn is considered to be carbon neutral because the CO2 it consumes while growing offsets the CO2 it produces when burned. As a result, burning corn is much better for the environment than burning fossil fuels.
- Supports local farmers. By purchasing corn directly from local farmers, you’re supporting local businesses instead of big utility companies.
Disadvantages
- Upkeep. Approximately 60 pounds of corn needs to be hauled from storage to the hopper every day. It also needs to be cleaned about twice per day.
- Requires electricity. Corn stoves need electricity to function. If you’re in an area that has a lot of power outages then it may be a good idea to have a generator or backup batteries on hand.
Types Of Corn Burners
Freestanding Stove
While freestanding corn stoves and wood stoves look very similar, they actually operate quite differently. For starters, corn stoves have a lid on top that leads to a hopper. Once you fill it with corn, the corn travels through a gravity-fed auger system which leads to the burn chamber.
Unlike a wood stove, a corn stove has a small firepot at the center of the burn chamber where the fire burns. It’s important to note that the fire does not fill the entire burn chamber; just the firepot. Some models even have a viewing port that lets you monitor the fire.
Corn stoves vary in operation, but most will have some type of control panel built into it. You can usually adjust the heat output, which in turn affects the feed rate of the corn, and thus the intensity of the fire. Some stoves will also allow you to choose between different feedstocks, such as wood pellets or corn.
To help feed the fire with oxygen, some stoves will suck outside air into the burn chamber while others will use ambient air from inside. Both of these methods use a small, built-in electric-powered fan to bring in air. Some stoves use a 12v fan to make it easier to run on a backup battery in case of a power outage.
Finally, the exhaust is routed outside either by a vertical flue or a horizontal one.
Fireplace Insert
Much like a wood-burning or gas insert, a corn-burning fireplace insert has a large viewing window in front and comes with a trim kit to fit. However, that’s where the similarities end.
For one, there are no flush-mounted corn fireplace inserts. They all stick out from the wall a few inches. That protrusion is where the corn hopper is accessed, usually by a small lid or door. And because of the space limitations of an insert, the hopper is usually smaller than that of a freestanding stove.
Secondly, the fire burns nothing like a gas or wood-burning insert; it burns just like a freestanding corn stove. The corn is fed from the hopper through an auger system that leads to the firepot. A fan forces air to the burn chamber to feed the fire and the fire’s exhaust is routed outside.
Forced Air Furnace
Corn-fueled forced air furnaces burn corn and route the fire’s heat through heat exchangers located throughout the house to warm the ambient air. These furnaces are bigger than freestanding stoves and inserts. They consume a lot more corn and are meant to heat much larger areas, usually entire structures like pole barns or small warehouses.
While the heating method is different than a freestanding stove or insert, the burning process is much the same. Corn is fed through a very large, multi-bushel sized hopper which then gets sent through an auger system and into a firepot. A blower fan feeds air to the fire and the exhaust is routed outside through a stainless steel vertical (or sometimes horizontal) flue.
Hot Water Boiler
A corn-burning hot water boiler heats water for radiant heating systems, like radiators or in-floor heating. There are indoor models that sit inside your house, as well as outdoor models meant to sit outside in a shed or similar enclosure. If you already have a natural gas boiler, the corn boiler can be plumbed in series with the old one for a backup heat source.
Much like the forced air furnaces, these boilers are meant for heating large areas like homes or small warehouses. They have very large hoppers that will last for multiple days before they need to be refilled again.
One of the biggest advantages of an outdoor boiler is that all the mess that comes with burning and storing corn stays outside and out of the home.
Agitator vs Non-Agitator
We’ve broken down corn burners into the four main types: freestanding stoves, fireplace inserts, forced air furnaces, and hot water boilers. But there is a subsection to all of these: corn burners that have agitators and those that don’t.
There are two lines of thought when it comes to agitators:
- Agitators disrupt the burning and gasification process, which introduces cooler temperatures and causes less of a percentage of corn to be burned. More ash is then pushed into the air where some sticks to the inner sides of the burn chamber and some escapes through the flue.
- Stirring and agitating the corn introduces more oxygen to the fire, making for a more complete combustion process.
It’s clear that some agitator burners work better than some non-agitator burners, and vice versa. It ultimately comes down to the make and model and how well they’ve implemented (or not implemented) the agitation process.
With an agitator, you don’t need to remove any clinkers. You may need to clean out the ash pan once every few days, but it can basically run unattended (with the exception of refilling the hopper).
With a non-agitator corn burner, you will need to remove the clinkers daily, sometimes twice per day.
Corn As A Fuel
Buying Corn
Type of Corn
On your journey to find a corn provider, you may come across seed corn. Seed corn is generally much cheaper than regular dried corn, but it should NEVER be used. It’s covered in toxic pesticides, making it very dangerous to handle and burn.
The only type of corn you should be burning in your stove is dry corn with a moisture content of 15% or less. Corn won’t combust if it isn’t dry enough, so the lower the moisture content, the better.
Grain elevators and most farmers will have a digital grain tester, so it’s important to get that squared away during the buying process. If you grow your own corn or acquire it from a local farmer who doesn’t have a tester, you can buy your own corn moisture tester and do it yourself.
Contacting A Grain Elevator
Grain elevators sell corn in either metric tons (1,000 kg), US tons (1,000 lbs), or bushels (56 lbs). Make sure you figure out how much corn you need before calling.
When you call, ask about the price but don’t mention how much you need or what the corn is going to be used for. There are some places that raise the price for corn burners. These places sell so much grain that they’re actually doing you a favor by selling to you. It’s best to give them as little information as possible so that they don’t upcharge you.
Also be sure to ask them if the corn has been screened. If they offer that service, you may have to pay an additional fee. It may be worth it to pay the fee to have the corn screened instead of having to do it yourself.
Contacting A Farmer
If you live in a small town then you probably know where some of the local farms are. If not, ask your friends and family if they know of any corn farmers. Posting wanted ads in local social media groups works as well.
Once you have some leads, find their contact information on their website or in the phone book. Call them up and explain to them that you’re looking for dry corn to use with a corn stove. Many farmers will be sympathetic to someone who wants to heat their home naturally.
If they agree to sell to you, don’t dicker with them on price. Much like grain elevators, they don’t need to sell to you. If you’re not happy with the price, thank them and tell them you’ll get back to them. At this point you can call around for a better price.
Hauling Corn
Grain Elevator
When you arrive at the grain elevator, you’ll pull your truck into the weigh station. Once your truck is weighed, you’ll head to the dumping area.
At this point, it’s a good idea to roll all your windows up, as it can get very dusty when the corn is dumped. Most grain elevators use an overhead dump so precision filling any kind of container is out of the question. Your truck bed should already be sealed so corn won’t spill out through the crack in the tailgate. You can use duct tape or line the bed with a large tarp.
Once your truck is filled with corn, head back to the weigh station to be weighed again. You’ll pay for your corn and you can head home.
Local Farm
If your local farmer has a large scale then you’ll go through the same weighing process. Otherwise, the farmer will just eyeball the amount. More often than not, they’ll be generous on the amount and end up giving you a bit more. For scale, a standard 8-foot truck bed holds 50 bushels of corn.
Make sure you have cash on hand (in all denominations) to pay them. You can throw them a few extra bucks for doing you a favor and selling to you, which is a good way to win them over so that they make time for you again in the future.
Cleaning Corn
Screening is the process of cleaning your corn from all the cracked kernels, fines, and other debris. Corn is a delicate grain that breaks apart the more it’s handled, so you’ll never be able to remove all the fines, but it’s necessary for a less messy and cleaner burn.
If your corn didn’t come screened then you’ll need to do it yourself. You can use a fanning mill (ebay link) or winnower, but those are large and very expensive.
Luckily, we were able to find a much more affordable corn cleaner (ebay link) at a fraction of the price. It filters larger debris like husks and rocks, as well as fines and smaller particles when connected to a shop-vac.
Storing Corn
How you decide to store your corn depends on the quantity. For large quantities, you may want to use a feed bin. They come in all sizes, but 40 bushel and 65 bushel sizes are the most common and are perfect for storing corn for the winter. Since they’re built with metal stands, the grain sits off the ground and keeps rodents out.
For smaller quantities, 55 gallon drums and 275 gallon IBC totes work well. If you decide to use 55 gallon drums, make sure you buy lids with locking rings. It helps keep pests and moisture out.
If you decide to use IBC totes then you may need to get creative, as they’re not meant for dispensing corn. You can go the route of cutting the top off and replacing it with plywood for easy access, but you need to make sure it’s completely sealed.
In our opinion, a better approach is to remove the dispenser and attach a PVC pipe and cap to the tote. The video below illustrates this well:
Whichever storage method you use, just remember that rodents will get into your containers if they have the chance. They can smell the corn and can be very clever when they need to be. Keep your containers off the ground so that there’s no way for them to climb up and reach the bins.
Other Grains As Fuel
Corn stoves aren’t limited to burning corn; they’re capable of burning lots of other grains too. Whichever grain you decide to burn, be sure to keep it clean. Stray pieces of straw and other debris have been known to cause problems with the auger.
Below is a partial list of fuel you can burn in a corn stove:
Fuel Source | Unit | BTUs Per Unit |
---|---|---|
Alfalfa Pellets | 1 Pound | 7,730 |
Aspen Pellets | 1 Pound | 8,500 |
Corn (Gluten Feed) | 1 Pound | 8,095 |
Corn (Shelled) | 1 Pound | 8,100 |
Corn (High Oil) | 1 Pound | 8,480 |
Corn (Waxy) | 1 Pound | 8,110 |
Dried Distillers Grains (With Solubles) | 1 Pound | 9,420 |
Dried Distillers Grains (Without Solubles) | 1 Pound | 9,845 |
Hardwood Pellets | 1 Pound | 8,570 |
Oats | 1 Pound | 8,240 |
Soybeans | 1 Pound | 10,230 |
Soybean Hulls | 1 Pound | 7,570 |
Straw-Wheat Pellets | 1 Pound | 7,375 |
Straw-Oat Pellets | 1 Pound | 7,625 |
Sugar Beat Pulp Pellets | 1 Pound | 7,345 |
Sunflower Hulls | 1 Pound | 9,655 |
Wheat Middlings | 1 Pound | 8,415 |
Wheat (Hard Red Springs) | 1 Pound | 8,060 |
Heating Efficiency
Fuel Cost Formula & Comparison Table
Burning corn is one of the mose efficient ways to heat your home. Use the following formula to see how the cost stacks up against other types of fuel:
Cost per million BTUs of energy = (fuel cost per unit / BTUs per unit) X 1,000,000
For example, if dry shelled corn costs you $3.10 per bushel then the calculation would look like this:
Cost per million BTUs = ($3.10 / 500,000) X 1,000,000
Cost per million BTUs = $6.20
Now compare that to diesel fuel with an average cost of $2.41 per gallon:
Cost per million BTUs = ($2.41 / 139,000) X 1,000,000
Cost per million BTUs = $17.34
Since fuel prices are constantly fluctuating and changing depending on where you live, you’ll need to plug your own cost of acquisition into the formula. The rest of the information can be found in the table below:
Fuel Source | Unit | BTUs Per Unit |
---|---|---|
Corn | 1 Bushel | 500,000 |
Diesel Fuel | 1 Gallon | 139,000 |
Gasoline | 1 Gallon | 124,000 |
Propane LPG | 1 Gallon | 91,330 |
Natural Gas | 1 Cubic Foot | 1,037 |
Wood | 1 Pound | 8,000 |
Wood | 1 Cord | 20,000,000 |
Coal | 1 Ton | 28,000,000 |
Butane | 1 Cubic Foot | 3,200 |
Heating Oil | 1 Gallon | 139,000 |
Electricity | 1 Kilowatt / Hour | 3,412 |
Pellets | 1 Ton | 16,500,000 |
Crude Oil | 1 Barrel (42 Gallons) | 5,800,000 |
Heat Loss & Burner Size
When trying to figure out what size corn stove you need, one of the biggest oversights is your home’s heat loss. It doesn’t matter how well insulated your home is, if it’s colder outside than it is inside, you’re going to lose heat through cracks, crevices, and walls.
Figuring out your home’s heat loss is fairly complex and has lots of variables, but this heat loss calculator does a great job of calculating it and letting you know exactly what size corn stove you need.
With the calculator, simply enter the dimensions of the area (as well as the dimensions of the windows and doors) that you wish to heat and select ‘input data’. Next, fine tune the column on the right based on the chart above it and select ‘calculate’. It will automatically calculate your home’s heat loss and let you know what size corn burner you need (in BTUs/hr), based off the temperature difference of outside air vs inside air.
Installation
Pre-Burning
Before installing your corn stove inside, it’s a good idea to first set it up outside and burn off all the paint fumes, manufacturing oils, and other chemicals for about an hour. Once that’s done, it’s ready to be moved inside.
Location
Corn stoves should almost always be installed in living spaces and not in the basement. Not only are uninsulated basement walls terrible for heat retention, but the stove will need to be big enough to heat both the basement and the upstairs.
In a 1,500 sq/ft home, you would need a stove capable of heating at least 3,000 sq/ft. So unless the basement is also a living area that gets used frequently, a corn stove should generally be installed on the main floor. Furthermore, it should be installed in a central location on the main floor in order to maximize heat flow to other rooms.
It’s also worth noting that a corn stove should never be installed in the garage, as it’s most likely against fire code.
Safety Requirements
Be sure to follow the manufacturer’s guidelines when it comes to installation requirements. The stove most likely needs to have a certain clearance from combustible walls and/or may require a brick hearth to act as a heat shield.
Vent Pipe
As a general rule of thumb, you should use no more than 15 feet of pipe between the stove and chimney. When connecting the pipes, the crimped end should be on the bottom in order to prevent condensation leaks.
If you’re installing a corn stove inside, you should be using 6″ double wall stainless steel pipes. Otherwise, single wall pipes should suffice. They must be either AL29-4C stainless steel or Type L pipes, though. Do not use Type B. Corn exhaust is very corrosive so you need to use the right materials.
Operation & Maintenance
Burning Corn
Starting A Fire
Corn burners that have electronic ignitions (instead of fuel heating rods) are not able to start fires, so you’ll need to start one yourself. Here’s a great method:
- Soak some wood pellets in a liquid fire starter like gelled alcohol or methyl hydrate.
- Dump a small amount of corn into the firepot.
- Dump the soaked wood pellets on top of the corn.
- Use a long fireplace match or torch to light the pellets.
- Once the fire is lit, turn on the stove.
Maintaining A Fire
Once your corn stove is lit, it should take care of itself with its automatic feed system. With time, you’ll figure out how much corn your stove goes through on a daily basis and you’ll be able schedule hopper refills accordingly.
Your fire should burn with a bright yellow flame. If the flame is dark orange, it means that the fire is starved of oxygen. The most common cause is that the exhaust is plugged with ash and soot, which will need to be cleaned.
Accessories
Fire Poker
A fire poker is a must. You can break up clinkers as they start to form or you can knock off buildup from the firepot or stirrer (if your stove has one).
Stove Fan
If you’re trying to heat multiple rooms with your corn stove then a stove fan is a step in the right direction. They’re made of all metal and sit on top of the stove. Instead of using batteries or an electrical outlet, it’s powered by the heat generated from the stove.
Heat Reclaimer
A lot of heat generated from your stove ends up escaping through the flue. A heat reclaimer attaches to the exhaust pipe and captures that heat, dispersing it back into the room.
Thermometer
With a corn stove, you want to monitor the temperatures of the firebox and the stack (or flue). To do this, you can either use magnetic thermometers or an infrared thermometer.
With magnetic thermometers, you can stick them to the inside wall of the firebox and the outside of the flue. It’s a good idea to take note of the temperatures when the stove is working fine. That way, you’ll have a baseline to compare to if your stove isn’t working properly.
A better solution is to use an infrared thermometer. You won’t be able to glance at the stove and monitor it constantly, but it’s a far more effective way to read the temperature. You can point it anywhere on the stove and it will give you an accurate measurement. It’s a great tool to have for other projects as well.
Ash Vacuum
An ash vacuum makes cleanup much easier. They have a metal waste bin and are specially built to safely suck up hot ash. As tempting as it might be, do not use a shop-vac to clean up ash unless the ash is completely cold. Sucking up hot ash WILL start a fire in your home.
Cleaning
Keeping your corn stove clean has a direct effect on how efficient your fire burns and how well it heats your home. You’ll need to clean out clinkers, ash, and soot on a regular basis.
Preparation
Soot is very messy and hard to get out of clothing and skin. Before you even begin cleaning, make sure you’re wearing old clothing that you don’t care about getting dirty. Then, get a pair of rubber gloves to keep your hands clean and a mask to prevent soot inhalation. Now you’re ready to get started.
Emptying Clinkers
Clinkers are the brick-shaped debris that forms when corn is burned. Some stoves are able to remove these automatically, but most stoves require manual removal up to twice per day. The video below shows you how it’s done:
Ash Removal
As with clinkers, ash should be cleaned out regularly. You can use a brush to brush excess ash into the ash pan, but a much easier and cleaner way is to use an ash vacuum. They’re specifically designed to safely handle hot ash.
Glass Cleaning
If you have a fire going, you can quickly wipe soot off the glass with a paper towel. Be sure to never use liquid cleaner on hot glass; wait until it’s cool.
When the fireplace is cool enough for a proper cleaning, be sure to use ammonia-free fireplace cleaner. It has to be ammonia-free, otherwise the cleaner could take off some of the tempered coating on the glass and cause it to crack and break when exposed to high heat.
End of Year
When the cold season is over it’s important to deep clean your stove for the year.
- Empty the hopper of all fuel.
- Remove firebox brick board.
- Vacuum the hopper, motor, and firebox.
- Oil the chain and spray some oil inside the firebox.
Safety
Positive Draft vs Negative Draft
If you’re planning on burning anything other than corn, like pellets or other fuel, then you will need a negative draft stove. If you’re only going to burn corn then you will need a positive draft stove.
The fuel in your hopper acts as a seal for the fire’s exhaust. When the hopper gets low on fuel, some of that exhaust can escape into your home. Since corn only releases carbon dioxide when burned, there’s no real safety hazard.
Pellets, however, release carbon monoxide when burned. With a low hopper, carbon monoxide poisoning is a very real (and extremely dangerous) threat.
Unlike corn, which burns very fast, pellets smolder and burn more slowly. Coupled with the possibility of gases escaping through the hopper, you can see why a negative draft is necessary.
Fire Extinguisher
It should go without saying, but you should always keep a fire extinguisher (rated for at least Class A fires) in the same room as your corn or pellet stove. Powder fire extinguishers are rated for Class A, B, and C fires and are great to have in the house.
It’s also important to make sure your fire extinguisher(s) are still functional. They usually last between 5 to 15 years, but you can check the pressure gauge to be sure. If the needle is in the green, then it’s good. Otherwise, it needs to be replaced.
Seed Corn
Seed corn is often cheaper than regular corn, but it should never be burned. It’s covered in toxic pesticides that can get on the skin and in the lungs.
Liquid Fire Starters
If you’re going to be using a liquid fire starter, make sure you only use it on a cold stove. Using it on a hot stove is very dangerous, as it can ignite the fumes and cause unexpected fires to break out.
Hot Ash Cleanup
Never use a shop-vac to clean up hot ash from your stove. They’re made out of plastic and are not designed to handle extreme temperatures. Using one will most likely start a fire.
Instead, use an ash vacuum. They’re built with a metal collection container and are designed to handle hot ash.
Stove Heat
Corn stoves are primarily made of metal and can get very hot with an active fire. It’s best to keep small children and pets away.
It’s also a good idea to follow the manufacturer’s guidelines for wall clearances and heat shields, such as a brick hearth.
Frequently Asked Questions (FAQ)
Can you burn corn in a pellet stove?
You can burn a mix of 75% wood pellets and 25% corn in a pellet stove, but no more than that. Pellet stoves use an auto-ignition system that won’t work with high percentages of corn.
Why does my new corn stove smell?
During your first few fires, you may notice an unpleasant smell. This is the result of the paint and manufacturing oils being burned off. But no need to worry, the smell will eventually go away. You can also do a pre-burn outside before installation to prevent this.
What are clinkers?
Clinkers are the hardened, glass-like residue that results from burning corn. Some corn stoves are able to clean these automatically, while others require them to be manually cleaned.
Why does ash blow everywhere when I open the door?
This happens when you have a positive draft stove. To prevent this, turn off the fuel feed, wait until the flames die down, and turn then off the stove. The blowers will now stop and you can safely open the door to clean your stove.
What do I do with clinkers and ash?
Clinkers are mostly made of potash, which makes for a great fertilizer. Break up the clinkers and sprinkle them in your garden.