Although modern building techniques and materials have helped to provide more energy-efficient houses in a good number of areas of America the majority do require some form of heating for at least part of the year.
When and how much heat is required does depend upon the geographical location, as well as the age and construction methods that were used to build your home.
In this article, I’ll try to convince you that if you have an off-grid home, using a corn stove to heat it at least partially makes economic sense.
Pros and Cons of Corn as a Fuel Choice
Before we get into the nitty-gritty, let’s quickly review the pros and cons of using corn as a fuel source:
|Good for off-grid homes||It won’t keep a large home warm on its own|
|Unlike wood, you can grow corn year after year on your farm or homestead||Lower efficiency compared to wood|
|Corn price is pretty low||Clinker needs daily cleaning|
|It’s a great emergency alternative fuel choice|
How Homes are Heated
There are several options available to heat a home that is located in a residential area since it’s possible to have the necessary energy delivered to the house through a utility infrastructure.
Over the past few years, there have been several changes to what is considered the favored power source.
The preference is constantly changing according to location, financial, and global warming concerns. The desire to embrace the power that has been created in a more eco-friendly method using renewable resources is a strong driving force.
Today, natural gas that is piped directly into homes is the primary source of heating fuel in the majority of regions except the South, where more than 60 per cent of households favored the use of electricity.
Generally new homes that are being built nowadays use electricity for heating rather than natural gas due to changes in the way electricity is generated, and the better efficiency available in heating powered by electricity.
For several of the 200,000+ people that live off-grid in addition to various others in America who do not have access to or do not want to use traditional utility power supply alternative options are limited.
Corn Burning Stoves
A fairly recent innovation that is slowly growing in popularity is the use of corn as fuel to heat houses. Although the principle is similar to log burners using corn as an energy source does require a different type of stove.
Some stoves are designed to burn different forms of pelleted fuel. These may be used to burn wood pellets and corn, however it is best to verify a stoves ability as a stove designed purely for wood will be damaged if corn is used in it due to the increase in heat.
Despite a corn stove being demonstrated in the Oval Office for Jimmy Carter, the concept does not seem to have been taken on by most people.
A corn stove is similar to a wood pellet burning stove, it has a small combustion chamber that has been designed specifically to burn a dry granular fuel.
Corn pellets are dense and, therefore do not burn easily on an open fire. Corn pellets burn much cleaner than other fuels.
A fan inside the combustion chamber keeps the corn burning, which is fed into the stove at a constant rate from a hopper.
Once the corn has burned it falls to the bottom and forms what is called a clinker that should be removed daily to ensure the stove is functioning correctly.
Although some log burners have fans, they are not essential to the operation of the burners, as long as suitable wood is placed on the fire and the airflow is maintained it will continue to burn.
The burner does produce ash that needs to be cleaned out, however, providing well-seasoned wood is burned the amount of ash is not large and can be left for several days before removing.
There is a range of corn-fueled appliances such as stoves, hot water furnaces and heating furnaces manufactured by 20 companies. Often these appliances can be tailored to specific requirements.
Basic models that don’t require any electricity they do not have automatic fuel feeds or fans, they just burn the corn that is supplied manually in the chamber and radiate the heat into the room.
Efficiency is slightly reduced with this type of stove, but they still provide a reliable heat source.
Fully automatic systems will light the stove when it is turned on fuel is supplied at a constant rate from a fuel container. The flue provides heat to a heat exchanger that has a fan to circulate this heat into the room.
The advantage of an automated system is that similar to traditional heating it is possible to set a temperature and the stove will maintain that temperature.
This automated type of the system, similar to existing units in traditional housing, is a suitable solution, however not all house layouts facilitate the required heat flow to all areas of the house without using fans.
Corn stoves can be lit manually or automatically. To manually light the corn a tiny amount of wood is first lit in the chamber, once this fire is established the corn feeder can be activated allowing sufficient fuel to keep the fire alight.
For automatic ignition, a fuel heating rod is used to heat the corn until the ignition has taken place.
Depending on settings, several of these stoves will run in excess of twelve hours without the need to top the hopper up, or clean them out. Anyone who has used a log burner will appreciate the difference.
Depending on the logs used, they need to be added to the fire every hour or so. As such, a large supply of logs needs to be kept in the house to maintain the supply needed.
The corn stove could easily run through the night maintaining an adequate level of heat whilst a log burner will start to die down and reduce the heat being produced midway through the night.
Since the burning of corn does not produce the same levels of smoke as when burning wood it does not require the same flue system.
A wood burner, due to the extensive smoke and fumes that it emits needs to have a sealed flue that should be higher than any surrounding structures to prevent smoke from venting into the house.
Corn stoves only require ventilation via slight, vent pipes with as few elbows as possible through the external wall.
Automatic systems actually use the heat that is being vented out to preheat the air that is being passed into the combustion chamber, ensuring maximum efficiency.
The different emissions also mean that a corn stove is not covered by the same legislation regarding the installation and licensing, hence the majority of states don’t require them to be installed by a professionally registered installation engineer as do other stoves.
However, there are some states that my request significant changes to a property to use a corn stove.
Since these stoves were not assessed for emission standards they cannot be government certified, consequently, states such as Washington and California do not permit their sale. Homes in rural settings are far more likely to be able to install corn stoves with minimum restrictions.
When the corn has burnt it leaves incombustible ash and the residue of the corn that forms a mass that is called a clinker.
As the combustion chamber is small it is important that this clinker is removed on a daily basis to ensure the continued efficient operation of the stove. With care, the clinker can be removed with tongs allowing the stove to be kept alight.
Care should be taken with these clinkers as they are exceedingly hot and when removed they can reignite when they come into contact with air.
Some systems prevent the formation of clinkers or have rotating fuel grates that break them and deposit them in an ashtray to be removed when required. The clinker can be broken up and dug into the garden as it has mild fertilizer properties.
This is a far better option than log burners that produce larger quantities of ash that can be a messy task when they are being cleaned out.
Due to the way in which the corn is burned in a combustion chamber these stoves do not become hot in the same way as log burning stoves do, this makes them an excellent safe option when there are young children or pets in the household.
For some, this lack of heat is a disadvantage since it means that it is not possible to cook with them.
Why Corn Is a Good Fuel Choice
Corn is a beneficial fuel to burn, especially as in some areas of the country where there is excess available. It is especially suitable since the corn does not need to be food quality corn. The corn, however, does have certain requirements to create a product suitable to burn.
The price of corn some years ago was pretty steep, but in 2014 it started to fall dramatically, making it an excellent choice as a low-cost fuel. Prices have increased, however, purchasing larger quantities with greater discounts still makes this fuel a suitable cost-effective option.
Location is obviously a factor since for those living in areas where corn is grown will find the supply cheaper than in areas where there is none, consequently, transport costs may cause this fuel to be a more expensive option.
For some, there is the possibility of growing some if not all the corn required to heat their homes and water. However, although the corn can be burnt whole with reduced efficiency corn stoves require the corn to be removed from the husks.
The corn should be dried so it has a moisture content of less than 15%, with some stoves requiring 13% to achieve a maximum heat value.
The dry corn will also flow correctly through the fuel delivery system without jamming. Moist corn could also create storage problems in that it is more susceptible to spoiling.
Meticulous cleaning of the corn is essential since any debris from the husk or any other material will affect the fuel delivery, and the burning process. The base of the kernels has a reddish-pink material that is called red dog.
The red dog can contaminate the corn during the drying and handling process and will build up on the heat exchanger if burnt with the corn. Since this build up would reduce the exchanger efficiency it is important that it is cleaned regularly.
Corn is easy to handle and store, especially since the stove burns a tiny amount that is automatically fed to the combustion chamber as the heat per weight ratio is high.
Consequently, it is a simple, light job to keep the hopper topped up. Although storage of the corn does need to be considered since it is attractive to pests and rodents.
The Cost of Corn Fuel for Heating Your Home
To calculate the cost of heating a home with corn we need to quantify the following:
- Cost of the corn
- Energy derived per unit of fuel
- Efficiency of the appliance
6,800 to 8,500 BTUs can be produced from each pound of dry corn. The weight of a bushel of corn is 56 pounds. To produce one million BTU 2.2 bushels of corn are required
Corn stoves will produce anywhere from 13,000 to 60,000 BTUs or more.
Cost per million BTUs of usable energy = (Cost/unit of fuel x 1,000,000) ÷ (Energy content/unit of fuel x AFUE)
- The Cost/unit of fuel is expressed in U.S. dollars ($$)
- The Energy content/unit of fuel is expressed in BTUs
- The Annual Fuel Utilization Efficiency (AFUE) is in decimal form (80% efficiency = 0.8)
Estimating the cost of corn at $5.00 per bushel, in a stove with an AFUE of 80%, it’s possible to calculate the cost per million BTUs of usable energy:
Corn cost = $5.00 per bushel
Energy content achieved per bushel = 7,000 BTU/lb x 56 lb/Btu = 392,000 BTU
AFUE = 80% = 0.8
Cost per million BTUs of usable energy = ($5.00 x 1,000,000) ÷ (392,000 x 0.8) = $15.94
Therefore, to provide 1 million BTUs of usable heat to the house costs $15.94 if the stove operates at 80% efficiency, burning corn that costs $5 per bushel.
A home built to previous specifications will require approximately 100 million BTUs of usable energy for heating per year. The price of corn has been estimated but will vary according to location and quantity purchased.
In this example the cost per year to heat a house with corn works out as: $1594.00
The Cost of Corn vs. Other Fuels
|Fuel||Consumption||Estimated Expenditures||Change from Last Year||Approx. Heated Square Footage per Household|
|Heating Oil||707 gallons||$2,191||-5%||1,903|
|Natural Gas||746 therms||$1,082||-5%||1,814|
|Electric Resistance Heat||3490 kWh||$836||-1%||1,272|
Tip: make sure you get a stove that can use other hearing sources besides corn – just in case corn becomes unavailable or economically unattractive at some point.
There are numerous factors that mark the use of a corn stove an attractive option for heating a house, however, there are several factors that should be considered before deciding to change your current heating fuel.
The price of a corn stove ranges between $1000 and $3000, which is a similar range to both log burning and pellet stoves.
The availability of a ready supply of corn at a suitable cost is a major consideration that depends on geographical location.
As with several products, there are various grades or qualities of corn available for use, careful consideration should be made as to which is the best product.
The cost of corn fluctuates each year, according to harvest levels and commodity market conditions.
It could be a concern that what is a beneficial price now may change in the future to cause it to be prohibitive. However, fluctuation of energy prices is something that happens with all energy supplies.
Storing the corn requires careful consideration since it should be kept dry and away from insects and pests which will eat or infiltrate it if permitted.
The quantity of corn required is not the same bulk compared to that of wood. Wood is also problematic in storing as it is larger and bulkier than the equivalent supply of corn.
Corn stoves with electric fans that are constantly running and the noise of the corn being injected can at times become irritating, especially without the benefit of seeing a roaring fire.
With eco- friendly considerations being important, it should be considered that corn can be grown every season, whilst trees once cut will take numerous years for more to be grown to replace them.
Efficiency is, of course, a vital factor, what is the cost of heating the home with a corn stove.
As we saw, there is a variance in the cost of corn across the country, however for several areas with corn being available at a low price since, these stoves are considered to be approximately 85% efficient, usage of this type of stove is certainly a serious option for countless people.
Three years ago, I bought an off-grid Cortijo in a small valley in the Andalucian mountains. Although, perhaps the lifestyle is in my genes as my grandfather and his four brothers were Homesteaders in Alberta Canada in the 1900s.
The mountains of Spain are a difficult place to grow many of the flowers that I was used to in the UK. However, veggies grow well year-round. Peppers, tomatoes, potatoes, lettuce, cucumber, melons and chard all fare well in the Mediterranean climate. Almond trees provide me with a cash crop of around 1 ton while still retaining some to make almond milk and flour.