Heating & Cooling Your Home

More about combustion safety.

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• The Draft Process & Backdrafting

  Gases leave the house through a process called "atmospheric draft." Atmospheric draft occurs when the high temperature of the gas causes it to initiate and maintain an upward flow, or draft, out of the building via the chimney flue pipe. However, the draft process can be overcome and reversed by negative pressures in the house created by exhaust fans, clothes dryers and combustion appliances. This causes the flue gases to enter the living space by spilling out the flue. Soot and debris under the draft hood is a sign that this has been occurring.

• Reduce the Potential for Backdrafting

  • All Systems - Ideally, all systems that burn wood or fossil fuel should be sealed combustion units, which provide air directly from the outside to combustion equipment. All new homes built after December 31, 2004, are required by the Residential Energy Code to have outdoor combustion air delivered to all combustion appliances, including woodstoves and fireplaces. Another option is a power-vented unit, which uses a fan to force exhaust out of the house.
  • Woodstoves and Fireplaces - See that woodstoves and fireplaces have tight-sealing doors and no chimney leakage to the inside.
  • Unvented Heaters - If you choose to use an unvented or vent-free propane or natural gas heater in your home, be aware that you must also have an oxygen depletion sensor (often included in the unvented heater). Unvented heaters must be used in well-ventilated areas in conjunction with carbon monoxide detectors. Also be aware that these heaters introduce substantial amounts of moisture into your home, potentially leading to moisture-related problems.

• Other Important Safety Considerations

  To reduce the chance of fire, always maintain recommended clearances (distances from walls, floors, and other combustible materials to the wood stove or fireplace). You can find out about required clearances from the manufacturer, the installer, your local code inspector, or the fire marshal.

  Never store flammable liquids (such as paint, gasoline, etc.) near combustion equipment. Fumes can be pulled into the air intake or flue pipe, causing corrosion, and a spill can be quickly ignited by the flames.