How to Run HVAC Duct in 2×4 Wall?

Every building needs a proper ventilation system to protect your valuable properties from damage and losses. Having windows and doors is also a good ventilation source, but we cannot leave our home just on windows and doors mercy.

So, installing and running the proper duct system could ensure the proper ventilation. But how to run HVAC duct in 2×4 wall? It seems tough to install or run the HVAC in a 2×4 wall. 

But you may prefer professional services, though they are very costly. However, on the other hand, you can try the following guidelines to install or run the HVAC duct in a 2×4 wall yourself.

How to Run HVAC Duct in 2×4 Wall: A Detailed Discussion

You will need the standard duct of 4 inches to run through a 2×4 wall and will need to follow the below easy steps.

Step 1: by Step Guide to Run HVAC Duct in 2×4 Wall:

First of all, Map out the design for the duct in the 2×4 wall. If you are not experienced, then ask someone to map out the design. But if you have a few skills, you can also take out the design of your neighbor to draw a design for your duct. But make sure the design is mapped out according to the size and width of the duct.

Step 2: Mark the Design on a 2×4 Wall

Once you have mapped out the design, the next task is to mark the design on a 2×4 wall. Mark the particular points on the wall; make sure you have marked the points at enough distance from the windows or doors.

Step 3: Drill out the Hole in the Wall

Now drill out the hole in the wall but make sure the width of the holes should not be more than ¼ units. For better measurement, you can run a nail through the hole to get a view from the cutting.

Take a grille to drill the hole but take a large size grille; when you are marking a hole in a 2×4 wall, its width is 3.5 inches; you should use a grille of 6 to 8 inches.  Mark cuts on the wall but avoids applying too much force and damaging the wall.

Step 4: Install the b-vent Flue

The next task for you is to install the b-vent flue; never forget to install the b-vent because it will become difficult to install the b-vent once you have covered the wall.

Position the AHU, then return it towards the coil side.  Mostly the evaporator coil comes in the cased or uncased form.  Cased coils are easier to access than uncased. 

Step 5: Install the Plenum

Now install the plenum, an intricate part of the duct that provides the refined air to the main areas of your building.  You can install it on the air handler or with the evaporator coil. You can also adjust the plenum by cutting it up to 1 inch below the ceiling.

After cutting the plenum, attach it with the beginning and end of the plenum.  Next to that, arrange the supplies for the air duct.  It is better to arrange the supplies on the floor before installing them on the wall. 

Fit supplies in the S-cleats with the beginning and end of the joint, and after that, attach them through drives. You can design the point where you need a subsidiary duct to attach the top of the main trunk. Follow the same process for each side until you have fitted all the supplies in the HVAC duct.

Step 6: Install the Return Ducts that you can Install on Either Side

After that you need to install the return ducts that you can install on either side. You will also need to install the return airdrop that is vertically situated beside the air handler. The purpose of the return airdrop is to connect them with the fan and air handler.

Step 7: Seal all the Openings and Areas that Need Covering

In the end, you will need to seal all the openings and areas that need covering. It is an essential step because it not just gives it a perfect finish but also ensures its safety from dust, debris, and other issues. 

But before sealing the open parts of the duct on a 2×4 wall, double-check your work; otherwise, you may face difficulty opening the seal and recheck your work.


A proper ventilation system protects our home and offices from emergencies. Installation of an HVAC duct in a wall may seem a tough task. But if you follow the above simple steps, it may make your job easier and fine on completion. You can also save a lot of money by doing it yourself.


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