Straight Answers to Burning Questions:
Quick Tips For Cleaner, More Efficient Wood Heat


  • Wood Heat contributes to the conservation of the world’s non-renewable fossil fuels.
  • Wood Heat enhances the nation’s energy independence.
  • Heating with wood can save you money.


Q: How can I tell if a wood stove is a cleaner burning, high efficiency model?
Regulations enacted by the Canadian government require all wood stoves and wood-burning fireplace inserts manufactured and sold to meet stringent emission tests. An EPA label identifies a stove as a cleaner burning, high efficiency model, and is found on the back of every certified stove or insert.

Q: How can I tell if a stove or insert is sized right for my home?
Consider your geographic location and climate, the number of rooms you wish to heat, and construction features of your home such as room size, ceiling height, and insulation. Ask a hearth specialty retailer for information on the best stove for your space heating requirements.

Q: I already have an older stove. Is there anything I can do to make it burn cleaner?
Yes. Even if you can’t upgrade to a new EPA-certified stove or fireplace insert right away, you can still improve the performance of your current stove. Have your wood heating system inspected by a Wood Energy Technology Transfer (WETT) certified professional for proper installation, safety and efficient operation. You can also reduce emissions by burning only well-seasoned firewood or by starting your fire with a solid fire starter product.


Q: When installing a wood stove, what’s the first thing I should consider?
Make sure the wood stove and venting work as a system. It is important for the stove’s venting system to be sized properly, according to manufacturer’s instructions. Whether venting into a masonry or metal system, make sure the diameter of the chimney matches closely, but never smaller than the size of the stove’s flue outlet. Doing anything else adversely impacts emissions and safety.

Q: Can I install my own stove, or should I have the installation done professionally?
The Hearth, Patio & Barbecue Association (HPBA) recommends that all stoves and fireplace inserts be installed by a specialist certified by the Wood Energy Technology Transfer Inc. A (WETT) technician is a trained professional. A certified technician can save you time, money and frustration. Plus, it will give you the confidence that your stove is installed properly and safely.

Q: Where can I find a certified installer?
A hearth specialty retailer can provide you with installation by an WETT certified professional. Ask the retailer about the installer’s credentials. Does the installer have experience with the make and model of the stove you are buying? Is the installer WETT certified?

Q: What is the Wood Energy Technology Transfer Inc. (WETT)?
Wood Energy Technology Transfer Inc. (WETT Inc.) is a non-profit training and education association managed by a volunteer Board of Directors elected by holders of valid WETT certificates. Through its administrative designate, WETT Inc. functions as the national registrar of the WETT program. Through professional training and public education, WETT Inc. promotes the safe and effective use of wood-burning systems in Canada.



Q: How can I tell if I am operating my wood stove properly?
Check the smoke coming out of your wood stove chimney; the smoke is your operational barometer. If your fire is burning properly, you should only see the white transparent steam of evaporating water. The darker the color of the smoke (unburned fuel), the less efficiently you are operating the appliance. It may be necessary to adjust the operation of your wood stove to decrease the smoke.

Q: Why is wood smoke undesirable?
Smoke, in the form of solid particles (particulate) and volatile gases, is unburned fuel. An improperly operated wood stove fails to achieve the high combustion temperatures necessary to burn the particulate and ignite the gases. These gases and particulate contain half the heating potential of your firewood. The loss of this fuel up the chimney amounts to a loss of efficiency. Improperly operated wood stoves can also adversely affect air quality. However, the use of EPA-certified wood stoves and wood burning fireplace inserts, combined with the proper operation of all wood burning stoves and inserts, can decrease the level of polluting emissions by up to 85 percent.

Q: Are there times when my wood stove or fireplace insert will emit more smoke?
There are two periods in the operation of a wood stove most vulnerable to creating smoky emissions — during start-up and during refueling. However, these smoky periods can be dramatically minimized by proper operation.

Q: What can I do to minimize the amount of smoke at start-up and refueling?
Create the drafting conditions necessary to maintain clean combustion. “Good drafting condition” occurs when your chimney consistently draws air into the wood stove at a high enough rate to prove adequate oxygen for complete burning. To create this draft, you must “preheat the chimney.” Some chimneys require longer preheating periods than others, depending upon their height, outside exposure and construction. Typically, preheating requires 5-15 minutes of vigorous firing.

Q: How do I preheat my chimney?
At start-up, remove all but a thin layer of ashes from your firebox. Insert five to ten crumpled individual pieces of newspaper and dry, finely split kindling or a fire starter. Firmly open the air supply (dampers) to the wood stove and ignite the paper on all sides. You may find it necessary to leave the stove door slightly ajar during the first few moments of the fire. After the first load ignites, add more kindling until the chimney is preheated. The fire should burn briskly and be full of flame during the start-up if you are operating the wood stove properly. When reloading, rake the remaining pieces of hot charcoal forward to the front center of your firebox, place finely split pieces of wood in the back and on the charcoal bed and fully open the air supply. Using smaller pieces of wood during reloading encourages rapid reheating of the chimney. You’ll know the chimney is preheated when each large piece of wood you add to the fire burns vigorously, without a loss in intensity of the fire. Keep listening to the sound of the air entering the stove. A constant and rising movement of air signals that good drafting conditions have been achieved. Some wood stove manufacturers provide specific guidelines for start-up and preheating phases involving the indirect monitoring of chimney exhaust temperatures. Typically, chimney connector temperatures must reach 500-600 degrees F. before the chimney is fully primed. Follow your manufacturer’s instructions when temperature and start-up procedures are specified.

Q: Once I have preheated my chimney, how should I operate the stove?
Although all wood stoves require preheating during start-up and reloading, their operation afterwards vary somewhat. Wood stoves using catalytic combustors require the monitoring of temperatures and air supply to ensure the catalyst engages at appropriate times in the combustion cycle. Generally, catalytic stoves require lower combustion temperatures in the firebox to burn cleanly. At 500-1000 degrees F., the catalyst ignites, burning the volatile gases and particulate. Non-catalytic stoves attain much higher temperatures in the combustion path before the gases and particulate burn. Always refer to your wood stove manufacturer’s operation manual and follow the instructions for your particular make and model.

Q: Do I operate my stove differently in cold vs. warm weather conditions?
Yes. During the warmer seasons of spring and fall, control the total heat output by limiting the amount of fuel (wood) rather than by closing down the air supply. Make shorter, hot fires using more finely split wood. The actual air supply setting will vary according to your stove instruction, but the fuel loading will be consistently smaller. Let the fire burn out rather than smolder at low air supply setting. When your home requires more heat, restart the fire with kindling as always, but add smaller fuel loads. This allows your stove to operate at maximum efficiency and with minimum emissions. Avoid the temptation of building a big fire and then starving it for air.

Q: Is it important to have my stove and chimney cleaned?
Yes. Smoke rising through your chimney may condense and build up on the cooler inside walls forming a substance known as creosote which is volatile and can ignite and burn in the chimney. Many chimneys and installations are unable to with stand these dangerous creosote fires and the results can be tragic. Chimneys and vents for wood stoves and inserts also perform the necessary function of directly venting the hot gases from a fire away from the house. If the chimneys or vents are obstructed by debris or animals, the hot gases can be forced back into the home. At the same time, wood stoves and inserts require service to ensure they are operating correctly.

Q: How often should I have my chimney inspected and cleaned?
WETT Inc. recommends having your chimney inspected/ serviced/ mantenanced annually. Insurance companies within Canada often require WETT inspections to ensure a home with a wood burning unit.


Q: Does it matter what kind of wood I use?
Your fuel supply should consist of a mixture of hardwoods, like maple or oak, and softwoods, such as fir and pine. When first starting your fire, use softwoods. They ignite easily and burn rapidly with a hot flame. Hardwoods provide a longer lasting fire and are best used after preheating the chimney. If hardwoods are unavailable, you can control your fire’s burn rate by using larger pieces of wood.

Q: Is it important to season wood before burning it?
The seasoning, or drying, process allows most of the natural moisture found in wood to evaporate, making it easier to burn. A properly seasoned log will have 20%-30% moisture content. Wood only dries from the surface inward so un-split pieces dry very slowly. To properly season wood, split the logs as soon as possible and stack them in a dry spot for 6-18 months. Pile the wood loosely, allowing air to circulate through the split logs. Hardwoods take longer to dry than softwoods and humidity and temperature levels also impact drying time.

Q: What’s the best way to load wood into my stove or insert?
Avoid placing pieces of wood in parallel directions, where they may stack too closely. Vary the position of the wood in the firebox to maximize the exposed surface area of each piece of wood. Only use wood properly sized for your stove’s fire chamber. Complete wood combustion requires wood (fuel), temperature (heat), and oxygen (air) to burn completely and cleanly.

Q: Is there anything I shouldn’t burn?
Never burn garbage, plastic, foil or any kind of chemically treated or painted wood. They all produce noxious fumes that are dangerous and highly polluting. Additionally, if you have a catalytic stove, the residue from burning plastics may clog the catalytic combustor.


Source: http://static.hpba.org/fileadmin/factsheets/product/FS_WoodBurningFAQs.pdf