Solution 3.4 Installation and Operation Manual
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8.5 Supply of Combustion Air
In Canada, wood stoves are not required to have a supply of combustion air from outdoors (except
in mobile homes) because research has shown that these supplies do not give protection against
house depressurization and may fail to supply combustion air during windy weather. However, to
protect against the risk of smoke spillage due to house depressurization, a carbon monoxide
(CO) detector/alarm is required in the room where the stove is installed. The CO detector will
provide warning if for any reason the wood stove fails to function correctly.
8.5.1 Air Supply in Conventional Houses
The safest and most reliable supply of combustion air for your wood stove is from the room in
which it is installed. Room air is already preheated so it will not chill the fire, and its availability is
not affected by wind pressures on the house. Contrary to commonly expressed concerns, almost
all tightly-sealed new houses have enough natural leakage to provide the small amount of air
needed by the stove. The only case in which the wood stove may not have adequate access to
combustion air is if the operation of a powerful exhaust device (such as a kitchen range exhaust)
causes the pressure in the house to become negative relative to outdoors.
Some jurisdictions in the United States require that wood stoves have a supply of combustion air
from outdoors. If you do install an air supply through the wall of the house, be aware that its
pressure can be affected during windy weather. If you notice changes in wood stove performance
in windy weather, and in particular if smoke puffs from the stove, you should disconnect the
outdoor air duct from the stove and remove the duct. In some windy conditions, negative pressure
at the duct weatherhood outside the house wall may draw hot exhaust gases from the stove
backwards through the duct to outdoors. Check the outdoor air duct for soot deposits when the full
system is cleaned and inspected at least once each year.
8.6 Installing the Chimney Connector
The chimney connector is the single or double wall pipe installed between the stove flue collar and
the chimney breech. Single wall pipe components are available from most hardware and building
supply stores. These components are not usually tested to a particular standard and certified as
compliant. Therefore, a list of rules found in solid fuel installation codes apply to the installation of
single wall pipe.
Double wall chimney connectors are tested and certified. The rules for double wall pipe are found
in the manufacturer’s installation instructions. These rules will be very different than those for
single wall.
8.6.1 Installation of Single Wall Chimney Connector
The chimney connector assembly has been called ‘the weak link’ in the safety of wood heating
systems because failure to install the connector properly (which has been common in the past) can
result in house fires.
The best flue pipe assembly is one that rises straight up from the stove to the base of the chimney
with no elbows. Straight assemblies are less likely to cause problems like smoke roll-out when the
door is opened for loading. They are also more stable and easier to maintain than assemblies with
elbows. Horizontal runs of flue pipe should be avoided where possible because they reduce
chimney draft.
