Apr 7, 2007

Corn-Burning Furnace Saves Money

When my wife and I merged and we moved into her home, I was aghast at the cost of heating this “new” place. The price of propane was $1.76 a gallon and it was costing $120 a week during the winter of 2004-05.

I resolved to fix a few things. While the old farmhouse was well insulated, the forced air heating delivery and return system was not efficient and reflected the many additions the house had enjoyed in a century of life. That needed to be changed to get more bang for our buck.

The rising price of propane – $2.05 last winter – needed to be fixed, too. So, last fall we bought a corn-burning furnace. We had it installed, hooked it to the existing gas furnace and its forced air system, revamped the ducts and bought a wagonload of shelled corn.

It all worked just like the numbers said it should. Last winter, we bought 352,800 Btus of corn energy for about the same price as we could get 91,500 Btus of propane energy. The price of a bushel of corn and a gallon of propane were virtually identical. Bottom line, we reduced our home heating bill by 75 percent.

That’s right. We took a week’s worth of propane money and turned it into a month’s worth of corn heat. (I estimate about 80 percent of the savings came from the lower fuel cost and 20 percent from the better duct system.)

We invested $3,200 in the furnace and $800 in installing it and the new ductwork, and it’ll all be paid for in 40 heating-season weeks, or little more than two winters.

Burning corn is a little less convenient than burning propane, which is totally automated. With corn, I have to go to the elevator about once a month, move the corn (luckily by gravity) into a basement bin, put 200 pounds of corn into the hopper every other day and check the furnace each day. I have to keep duct tape on my old trailer so the corn stays in when I haul it. But the furnace stoker system is automatic and augers those kernels into the firepot, a small handful at a time, just as slick as can be.

The corn burns dirtier than I expected, so I shake out the fly ash every day. Every two weeks or so, I dump about 50 pounds of ash into my compost pile. I remove any accumulation in the metal chimney every couple of weeks. I’m going to have to power wash the east side of the house this spring because there’s some soot on it from the chimney.

The yard smells a little like popcorn.

If the furnace has a decent life (and who knows how that will work?), it should be a profitable investment. Right now, I feel good because I’ve shifted my reliance from foreign oil companies onto American farmers, whom I like and trust, and have gotten into a natural cycle. The furnace still emits carbon dioxide into the atmosphere, but the corn takes it out again as it grows, so it’s a sustainable cycle, not a depletion of fossil fuel reserves or a net cause of global warming.

I wish I could do the same with my car.

Farmers would like to help me do that as well, but the economics of ethanol for liquid fuel are not nearly as good as corn for home heating. Farmers should put more promotion effort into supporting the corn furnace industry.

There are several problems with ethanol.

The first is it’s formed by fermentation. Yeast and bacteria attack the sugars in corn, releasing about 20 pounds of carbon dioxide as they produce 20 pounds of ethanol. (The remaining 20 pounds or so in the bushel is used for livestock feed.) But a third of the energy is lost in the process of feeding bacteria.

The heat value of ethanol is about 80,000 Btus per gallon, only two-thirds that of gasoline.

When the ethanol promoters tell the public they can fill their fuel tanks with E85 for the same price as gasoline, they don’t tell them the whole truth: They have to fill the tank three times for every two fill-ups of gasoline. Ethanol is less energy dense.

It is easy to understand why farmers want the liquid fuel market. Liquid and gaseous fuels are so convenient. I can’t run a car on shelled corn.

But as I found last year, keeping a corn furnace burning was pretty easy.

And think about this. Corn prices last year were about $2 a bushel, a little more than twice what they were 40 years ago. Back then, I paid 25 cents a gallon for gasoline. The price is 10 times that today and rising.