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 efficiency.
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
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
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 system.
Chimney Placement and Sizing
Chimneys harness the heat of
the fire to create what's called a
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.
Also, between the higher and
lower pressure zones of the
home lies a neutral pressure