Effects of the Wind on Venting

Ventilation: Combustion Air Supply

The woodburning venting system may incorporate all the design considerations that promote good draft, and yet the system may not function properly. The problem may be one of inadequate combustion air supply, caused by lack of adequate air exchange rate in a tightly constructed house and/or competing sources for the limited combustion air supply.

Ventilation is the term that describes the movement of air from outside into the house. The National Fireplace Institute requires solid fuel appliances to be installed "in a location and manner so as to provide adequate ventilation and combustion air supply to allow satisfactory combustion of fuel, proper chimney draft, and maintenance of safe temperatures." It also requires that "Where buildings are so tight that normal infiltration does not provide the necessary air, outside air shall be introduced." We look now at the factors that affect ventilation and actions that can be taken to ensure adequate ventilation and combustion air.