Firewood Burning Tips from Good Wood Fuel Ltd.
The first step in efficient wood heating is to ensure that a Wood Energy Technology Transfer Inc. (WETT) Certified Technician installs your wood burning unit and its chimney according to current building code rules. This means having adequate clearance between the stove, its flue pipe and combustible walls and ceilings, and determining that the chimney is suitable for wood burning, is properly cleaned and in good condition. Your woodstove is part of a system, and all components of that system, from the stove door all the way to the top of the chimney must be in good working order to ensure efficient and safe heating with firewood.
Efficiency Depends on Good Fuel
Efficient, safe wood heating is impossible with unseasoned or green wood. Properly seasoned firewood has less than 20% moisture by weight. The moisture content of freshly cut wood, which can range from 35-70%, suppresses the combustion process. The higher the moisture content, the more energy is consumed heating and boiling the moisture in the wood rather than burning the fuel. Burning unseasoned wood produces an inefficient, smoky fire that is slow to start, difficult to sustain, and produces less heat. Wood that is not properly dried before burning will also cause creosote build up in your chimney, contributing to the risk of a chimney fire.
As a general guideline, firewood that is cut, split, and stacked in the spring will be ready for burning the following winter, however if properly stacked outside in the Nova Scotian summer, wood can season adequately in two months.
Wood should be seasoned outside, in an open area, so that air may circulate around it, it should be stacked raised off the ground and covered if possible. Drying may take longer for very dense wood such as oak, or for wood that must be dried in a damp climate.
Never store unseasoned wood in your home or basement, as the moisture leaving the drying wood will increase the relative humidity in your home. Higher humidity levels increase mould and mildew growth, which can cause health issues and damage to your home.
Don’t burn painted or treated wood or saltwater driftwood in your stove, and never burn garbage, plastics or rubber. These can produce toxic substances that affect the air you breathe and reduce your stove’s heating efficiency. To start a fire, use newspaper and small dry pieces of wood; never use liquid fire starters.
Firewood should be cut 2-4 inches shorter than your firebox, and should be split to a maximum of 4-6 inches thick. Small pieces of wood burn cleaner because they have more surface area exposed to the flame; this keeps your fire burning consistently clean and hot.
Kindling a New Fire or Adding Wood
The first stage of a fire, just after kindling or adding wood to a coal bed is usually the smokiest as the cool wood, the moisture, and the cool inside of the stove remove heat from the flames. During this stage, fully open all air inlets of the stove to provide as much oxygen as possible to the fire and produce a high flame.
It might appear that this initial hot burn permits too much heat to escape up the chimney, but it is a necessary part of an efficient fire. This rising heat warms the chimney to produce a strong draft, and helps keep the flue liner clean by loosening creosote that may have been deposited by the previous fire. The hot initial burn also drives moisture out of the wood and gives an ignition source for the smoke that is released from the wood.
Most of the heat energy in burning wood is released as a bright flame. The turbulence created by these flames creates good mixing of the combustible air and the gases that are released from the wood as it heats up. It is the heat of the fire that ignites and burns these gases and in turn produces more heat. In contrast, the dense smoke from a slow smouldering fire is potential heat energy that escapes up the chimney to pollute the outside air or cling to the chimney flue as creosote. Therefore, to gain the most heat from each load of firewood, the wood should be flaming throughout the burn cycle until it is reduced to charcoal.
Some homeowners stuff their stoves with wood and burn the wood very slowly overnight. This is one of the worst things to do; smouldering fires are inefficient and dangerous, wasting wood, and depositing creosote in the flue. With seasoned wood, careful fuel loading and proper air settings, it is usually possible to maintain a sufficient burn overnight.
Your Wood Burning Appliance
If even after all of these considerations you still have dense smoke coming from your chimney, the problem may be with your wood-burning appliance. You may want to consider replacing your stove with a newer unit that make the most of more advanced technology. The carefully designed internal combustion features and clear viewing glass of these new stoves make clean and efficient wood heating much easier and enjoyable. You can readily identify these advanced wood burners as they are tested and certified as clean burning according to the Canadian Standards Associates (CSA), Standard B415 or by the United States Environmental Protection Agency (EPA).
Every home should have a system of smoke detectors installed outside each bedroom and sleeping area, on each level of your home, including the basement. Ensure the room in which your wood stove is located is also equipped with a smoke detector.
Carbon monoxide detectors are also recommended. These alarms sound when this odourless gas is released into a room from a receding charcoal fire, a chimney back draft or blockage. Carbon monoxide detectors should be installed near bedrooms or sleeping areas and on all levels of the house. They should not be installed directly above or beside your woodstove, as a small amount of carbon monoxide may be emitted at start up which will cause your alarm to sound.
Class A fire extinguishers are also recommended for homes that heat with wood. The extinguisher should be mounted on a wall in a visible location and out of reach of children, just inside an entrance door is an ideal. Ensure all the adults in the home know where the fire extinguishers are located and how to use them.