How to calculate the effective
duct length
The overall duct length will determine
the duct diameter (see the "Additional
duct lengths" table). In Canada the
exhaust duct must be 4" (102 mm) in
diameter.
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Measure the actual duct length
needed to go from the dryer’s
exhaust connection to the vent outlet:
1. Establish the number of elbows or
bends necessary, noting the type of
bend, angle and radius involved
(see the "Additional duct lengths"
table).
2. Add the additional duct length (as
derived by using the values
specified in the "Additional duct
lengths" table) and the actual duct
length to get the effective length.
Note:
Maximum effective duct lengths:
4" (100 mm) diameter
66 ft (20 m)
5" (125 mm) diameter
115 ft (35 m)
6" (150 mm) diameter
108 ft (33 m)
* For rigid ducting only!
Local building codes may vary.
When flexible metal duct (transition
duct) is permissible by local building
codes, the total length must not
exceed 7'10" (2.4 m).
See the "Additional duct lengths"
table for more information on
maximum duct lengths and number
of bends.
Using the ring adapter up to an
effective duct length of 33 ft (10 m) and
a standard duct diameter of 4"
(100 mm) will provide optimal drying
times and energy consumption.
Do not use the ring adapter if the
effective duct length is more than 33 ft
(10 m).
Effective duct lengths over 66 ft (20 m)
require a larger duct diameter.
Longer ducts may lead to slight
decreases in dryer efficiency if the
necessary duct diameter is not
employed.
Installation
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