Preparing for Winter – Local Energy

For the last 17 years our family has used wood as our primary heating source. Not only is firewood a local, renewable energy source, it is also a relatively clean fuel. That seems surprising when you see the smoke going out of the chimney. However, there is something that has to be taken into consideration. If wood is left to rot or is ground up into mulch and left to decompose, gases are released into the atmosphere. If the amount of greenhouse gases that are released from decomposing is subtracted from the emissions from burning the wood, wood turns out to be a relatively clean fuel as compared to fuel oil. Unlike wood, oil that is left in the ground does not pollute the environment. It is when oil is burned that it creates pollution.

I found a good resource on the internet on how to make improvements to a wood burning stove to make it more efficient and produce less smoke. It is  On the right side of their website are the links to several free publications that they have. Using the principles in those publications, I designed a heat exchanger that replaced our existing stove pipe. The heat exchanger is about four feet high and 11 inches in diameter. The lower 15 inches is an insulated section where escaping unburned gases are ignited and burned. Just above that section, an 8 inch pipe draws in room air from the back. The 8 inch pipe goes up the center of the heat exchanger and is open at the top into the room, allowing heated air to flow into the room. The smoke from the wood stove travels in the space between the 8 inch pipe and the 11 inch pipe. The smoke exits out the back of the heat exchanger into the chimney.

The heat exchanger works better than what I had hoped. It has reduced the amount of smoke produced, but even better, it has almost doubled the heat output of the wood stove. It is free heat that we have been losing up the chimney! What is important to me too is that Cathy likes the design which is not as overbearing as the ones on the website which use big 55 gallon drums for the heat exchanger. Attached is a picture of the heat exchanger.

One of the things that is important in heating with wood is to make handling the firewood as easy as possible. In the picture you will see the wood box that we built last year and is working well for us. It is essentially a hand truck style wood box that has large casters on the front which allow the wood box to be rolled back against the wall with the opening to the front. The wood box can be tipped back like a hand truck to make it easy to take out to the wood pile, load it up, and bring back to the house. We have two wood boxes so that we can have plenty of wood and don’t have to go out in the rain or snow and get wood.

Woodstove Heat Exchanger