Also, between the higher and lower pressure zones of the home lies a neutral
When the top of the chimney is located above the home ceiling (as it should
be), the chimney's neutral pressure zone is above the neutral pressure zone
of the house. Such proper chimney placement creates a gentle flow of air
into the appliance and out the chimney even when no fire burns.
If you are designing or building a new home, consider placing the chimney
inside your home. A more traditional chimney, constructed along the outside
of a home, will lose valuable heat to the cold, outside air.
If the chimney air temperature falls below temperature inside the house, the
cold acrid smelling chimney air will be pulled into the house by the low
pressure of the stack effect. In such a scenario, the house becomes a better
chimney than the chimney. So when a fire is lit, smoke fills the room.
Chimneys must match the size of the appliance, meaning the flue size should
match the stove outlet. If the chimney is bigger than the stove or fireplace
outlet, exiting exhaust slows, increasing creosote buildup and decreasing
High-performance chimneys are also insulated. Older masonry chimneys can
be relined to safely and efficiently connect them to newer high-efficiency,
wood-burning appliances. Again, the chimney liner should be continuous from
the appliance outlet to the chimney top. It is not uncommon to pay as much
for the chimney as for your appliance.
Free-standing wood stoves exhaust into a connecting pipe, which then
connects into the chimney. If the connecting pipe is longer than 8 feet (as in
a vaulted ceiling), you should consider investing in double-layer pipe with 1-
inch airspace between pipe layers.
Efficient modern stoves produce large amounts of heat. Much of this heat
can radiate from a longer length of single-layer pipe, slowing down the draft,
which can impact the overall efficiency of your wood-burning
Chimney Placement and Sizing
Chimneys harness the heat
of the fire to create what's
called a stack effect.
As the warm air from the fire
rises, cooler house air
rushes into the wood
burning appliance through
vents, providing the oxygen
the fire needs to burn.
Starting a fire with a good
hot burn will encourage this
healthy draft to flow.