How to Make a Wood Heater Burn Hotter

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Those of us who had some basic Scout training think we know how to build a fire. Wad up some paper, make a neat teepee of sticks on top, lay on a couple of pieces of kindling, light a match, and add chunks of firewood once it is all ablaze. And the basics are just that! But what if we want that fire in a woodburning stove or wood heater? What if we want more than a little basic fire for roasting marshmallows? I had to learn by experience how to make a wood heater burn hotter than a campfire.

I have used a number of woodburning appliances over the years, from Grandma’s antique enamelled Enterprise cookstove, to a sophisticated airtight wood heater made in Scandinavia. The principles are the same. Build the basic campfire starter, then add the appropriate wood.

Which Wood is Best?

Wood is a big factor in how hot the fire will be. While any old scraps will do for that campfire, to get a wood heater fire hot enough to do what it needs to do takes some planning. Dry wood is a necessity. By dry I don’t mean it isn’t dripping with rain, but that it has had the natural sap dried out of it. Firewood should be at least a year old to be properly dry. “Dryness” can be judged by the cut ends of the pieces. A dry piece of firewood will have obvious “checks” or cracks in it. It will be grey in color rather than yellow, white, red or tan. Softwoods burn hot and fast; hardwoods burn slowly. A fire that is only softwood, though, will produce more resin vapors, and will cause creosote build-up in the chimney, a source of chimney fires. Hardwood properly started will burn hot and more completely.

Fire Building Basics

Try building the fire this way:

  • Something flammable needs to go in first! Newspaper is the first choice, but it needs to be rough, plain paper, not glossy paper. The color-printed advertising inserts don’t burn very well. It used to be that the inks used in colored sections contained toxic chemicals, but most printing is now with vegetable-based inks. Still, the slick coating on the inserts traps the cellulose, so the old rough paper, printed in black ink, works best. Other good firestarters are very dry bark and dry grasses twisted together.
  • Small pieces of wood go over the firestarter, usually twigs or chips or slivers cut from a dry piece of wood.
  • Kindling is laid over these, and this is ideally softwood, well-dried, such as pine. Softwoods - mainly evergreens, trees that have needles year-round - ignite more easily and contain resins (pitch) that aid in ignition.

Once this foundation is laid, a match or igniter is applied to the paper, and all should be burning well in a couple of minutes. Now we add bigger pieces of softwood, or small pieces of hardwood. Hardwood is from deciduous trees, the trees that lose their leaves in the fall. Just a few pieces go on at this point, until they are burning well.

How to Control the Blaze

Wood heaters and stoves have controls on them to control the draft, or flow of air through the firebox. Sometimes these are levers, sometimes they are twist knobs. They open and close ports in the top or sides of the firebox to let air flow in and up the chimney. There is usually a lever or rod to control the flue, the opening into the chimney, usually at the back where the stovepipe meets the heater or stove. It takes some trial and error to set these so that the fire burns well. The rule of thumb is that the more air, the faster and hotter the fire will burn.

To make a fire hotter for a brief time, you can add small pieces of softwood. To make it burn hotter for an extended time, it is better to add some pieces of hardwood. Most wood sold by the cord for home use is cut either in heater or stove lengths, with the heater type being longer and thicker. Stove wood fits into a smaller firebox. In either case, split the firewood with a wedge and maul or a splitting axe to get more usable pieces. This is a matter of being prepared for the splitting; a splitting wedge and maul and a splitting axe need to be properly sharpened, and a hardwood stump of about six inches high and two feet in diameter makes the job easier.Keep firewood under cover. As the wood dries out, the cellulose of its cells will take up water from rain, snowmelt, or even a damp climate.

References: Author’s personal experience.