Home » Galvanized Duct, Pipe & Fittings » Tips on duct installation
Tips on duct installation

Prior to installing a duct system, you should:

  • Sketch out your layout.
  • Make a checklist of the duct, pipe and fittings needed to complete your installation.
  • Estimate the type of joints required.
  • Consult your store representative for assistance.
  • Check local building codes in your area before planning your installation.
Back to Top

About airflow

It is important to maintain a neutral pressure in the home by having balanced airflows between the supply and return system.

  • Airflow can be restricted by certain fittings and too many turns in a system.
  • Dampers allow for adjustments of air distribution.
  • Reducers can also balance your system.
  • Use the correct pipe size for your system.
    A too large or too small fitting can hamper airflow.


The total amount of air that your furnace or air conditioning system can move stays the same even if you add a branch.
Whenever you branch, you must reduce the size of the pipe to maintain air velocity.

  • For each branch of ductwork, determine your start point and your end point.
  • The new supply line should always be drawing off a main air supply duct.
  • Use a take-off when your start point is a rectangular main duct.
  • Use a tee or wye when your start point is a round main duct. 
    Tees split, but do not reduce, and an appropriate reducer must be added.
  • Use a boot when your end point is at a room floor, wall or ceiling.
  • Use elbows to make any necessary turns between the start point and end point. 
    A 90º round adjustable elbow can be adjusted to make any angle from 0º through 90º.

Top take-off



Angle boot




Back to Top

A few more tips

  • Sheet metal ducts must be insulated when located in an unconditioned space.
  • Try to avoid cutting by using full lengths of pipe.
  • Crimps must be placed so that the airflow exits at the crimped end.
  • Never locate ducts at the end of the trunk line run.
    The last take-off run should be located 12" - 18" from end.
  • Always stagger take-off ducts by 12" to maintain pressure.
  • When connecting ducts, cut an accurate hole; fasten components mechanically with at least one screw per side and seal leaks using a high-grade tape or preferably mastic.
  • It is recommended that all register boxes be sealed to the drywall or floor with caulking or mastic.
Back to Top

Some tools and materials you may need 

Back to Top
Tips on duct installation
Prior to installing, you should...
About airflow and branching
A few more tips
Some tools and materials you may need
Looking for a definition? Click here!
2017 Galvanized Duct, Pipe & Fittings 2017 Galvanized Duct, Pipe & Fittings 3.91 MB
Galvanized Duct Assembly Installation Galvanized Duct Assembly Installation 0.04 MB
Oval Duct Catalogue Oval Duct Catalogue 1.81 MB
Imperial Group
Head Office & Customer Service
Contact us
Site Map
Awards & Accolades
In the Community
What's New?
Upcoming Events
Registers & Grilles
Venting & Flexible Duct
Imperial Air Technologies
Railing, Columns & Fencing
Galvanized Duct, Pipe & Fittings
Steel Stud, Channel & Trim
Air Filtration
© 2019 Imperial Manufacturing Group|All rights reserved|A NuFocus Online Solution
Content Support
E-mail Now