Clean-energy security
As energy prices rise, and the full environmental impact of fossil fuel use comes into focus, more and more Canadians are looking to wood as a sustainable, affordable source of heat. This makes sense given the landscape that surrounds many of us, and while firewood can be burned in a freestanding stove, a masonry heater or a basement furnace, outdoor wood furnaces are a little-known option that’s worth looking at. Just before Christmas, I fired up an outdoor furnace I installed at my own place, and it addresses the kind of energy issues that more and more Canadians are concerned about.
All outdoor wood furnaces look like a metal garden shed with a short chimney. Feed wood into the firebox behind a door on one end, and the fire heats water in an insulated tank that’s also inside the structure. Pipe this hot water to a building through insulated underground pipes, extract the heat, then use it for space heating and to heat domestic hot water. This is the outdoor wood furnace proposition in a nutshell, and it offers unique advantages. By moving the fire outside, you sidestep the work of bringing firewood inside, the potential hazards of burning it there and the work of hauling ash back out.
Canada is at the leading edge of this technology, and as I’m discovering for myself, this heating option offers a range of benefits.
Outdoor boilers make wood cutting and splitting more efficient, because the work can happen right next to the place where the wood will be burned. The best setups include a wood storage shelter near the furnace, creating an all-weather place to keep wood as dry as possible over winter. Some users even have their wood splitter permanently parked in the shelter. Splitting and stacking happens all in one place, minimizing the chore of handling wood.
The fireboxes on most wood boilers are larger than you’ll find on even the largest indoor woodstoves. The smallest outdoor models can accommodate wood 20 inches long, but many larger boilers burn wood twice that long. Bigger wood makes for much less cutting time and more efficient use of your wood splitter. The bigger your wood, the less time it takes to prepare it.
Heat output is another unique feature of outdoor wood boilers, and this offers another efficiency. Even the smallest models are capable of heating a full-size home, with larger units capable of heating multiple buildings as well as heating domestic water, all from a single location. The work of tending one centrally-located fire is safer and easier than maintaining two or three fires, and makes it practical to handle more of your overall energy needs with wood.
Outdoor wood furnaces aren’t for everyone, but they do have a growing place in the rural and semi-rural Canadian heating scene. They make direct use of an energy resource that’s abundant and renewable across a large part of Canada, and the fact that it’s likely to stay that way may be the best benefit of all.