Wood stove health

Wood heating tips & tricks

Janet Moje
Left to right:  unseasoned green wood, one-year seasoned wood showing cracks in log, two-year seasoned wood showing cracks in log and bark.
Left to right: unseasoned green wood, one-year seasoned wood showing cracks in log, two-year seasoned wood showing cracks in log and bark.
Janet Moje PHOTO

Heating with wood and air quality is a controversial topic in our community. In truth, complete combustion of wood to carbon dioxide and water vapor does not produce any health-related air pollutants. Unfortunately, even with the newest stove and optimal conditions, wood stoves do not achieve complete combustion.

There are things we can do to improve the air quality for ourselves and our neighbours. Most tips listed here are inexpensive and simply require a responsible commitment from those who heat with wood. Let’s do what we can to improve our air this winter.

Understanding creosote

Whenever you burn any fuel, (wood, gas, oil) it creates air pollution. Some are cleaner than others but they all require burning fuel efficiently to reduce pollutants and ensure safety in the home.

Creosote is the residue from burning fuels and is made up of creosote, tar and soot.  Gas residue is mostly soot. Wood burning is mostly tar, but when you burn wood efficiently, it too is mostly soot.

First stage wood fires produce mostly soot. A fine, black dust, soot is easily cleaned out of pipes with a brush. An open fireplace with unobstructed airflow is the most efficient burn and best for stovepipes and chimneys.

Second stage fires create a tar build up that resembles black corn flakes. This is still fairly easy to clean with a brush. It is created by fires with restricted airflow, typical of air-tight stoves or fireplaces with glass doors.

Third stage fires create a heavy creosote build up. This concentrated fuel will condense on the inside of pipes, ignite and become denser. It looks like a runny tar. If not cleaned, this will continue to build a thick lining on pipes. Once it reaches ¼ inch thick, it becomes a serious safety hazard for chimney fires.

Poor burning habits will create a stage three fire: burning wet or green wood, construction wood, garbage, glossy paper, liquid fuel starters or dampening down air flow until your fire is smoldering.

All fuels can create carbon monoxide inside the home, an odorless, colourless gas that can kill you when in an enclosed space.


Safety Tips

  • Service and clean fuel appliances. Even changing a $5 filter can help.
  • Keep stove pipes and chimneys clean.
  • Only burn dry, seasoned firewood. Using unseasoned wood will increase your wood needs by 30%, and create more pollution for your neighbours.
  • Keep a plastic 1-litre bottle of water near the stove to toss inside in case of chimney fires. The heat will melt the plastic and create steam which can extinguish the fire.


Efficient Burning Tips

  • Warm flue for 10-15 seconds before starting a fire. This can be done by burning a rolled newspaper below the flue opening and create a good draft.
  • Use more kindling when starting a fire. It will create a hot fire faster.
  • Keep doors open for the first half hour of a new burn. It will reduce the amount of smoke produced.
  • Stack logs with space around them. It will prevent smoldering during the burn.
  • Burn hardwoods. They burn more slowly and produce less smoke.
  • Burn small, hot fires with visible flame to reduce creosote build up.


Environmental Tips

  • Wood burning produces breathable pollutants of smoke, creosote fumes and ash.  During periods of low wind and temperature inversions, these particles accumulate and irritate the respiratory system. Try to reduce wood fires during these times.
  • If you smell smoke in your house no matter how subtle, you are polluting your inside air. 
  • Visibly check the smoke coming out of your chimney. The more transparent it is, the more efficient your combustion. Heavy smoke means you are losing energy up the chimney and creating more pollution needlessly.
  • Don’t over dampen your fires. Proper air intake is necessary for good combustion.
  • Overloading stove and keeping dampers too low at night are major contributors to pollution. Keep air space around logs when loading stove.


Tricks and Gadgets

  • Invest in a good chimney brush and clean it at least once a year.  
  • Use a chimney/stove pipe cap. It reduces creosote build up by preventing the cooling of pipes from moisture, inhibits backpuffing (smoke in the house), and extends the life of your pipes.
  • Use a carbon monoxide detector (CO alarm $25-45).
  • Use a stove pipe thermometer (250 degrees F will prevent creosote condensation $10-25).
  • Use insulated pipes inside and outside the house. It reduces creosote condensation.