DUCT PIECES
EQUIVALENT
LENGTH
X NUMBER USED
= EQUIVALENT LENGTH
Rectangular to round
transition adapter
5 ft
X
( )
=
ft
Wall cap
40 ft
X
( )
=
ft
Round 90° elbow
10 ft
X
( )
=
ft
Round 45° elbow
5 ft
X
( )
=
ft
Rectangular 90° elbow
25 ft
X
( )
=
ft
Rectangular 45° elbow
5 ft
X
( )
=
ft
Roof cap
24 ft
X
( )
=
ft
Straight duct 6” round or
3 1/4” x 10” rectangular
1 ft
X
( )
=
ft
TOTAL LENGTH
=
ft
DUCT LENGTH CALCULATOR
Use the chart below to calculate the total length of the duct work being installed. The total length should not
exceed 140 feet.
INSTALLATION INSTRUCTIONS
10
