How To Run HVAC Duct In 2×4 and 2×6 Wall?

A good ventilation system in the house protects the valuable things in your house from damage. Though the windows and doors help in ventilation, it is not enough. That is why people want to have a proper HVAC system in their houses. But how do you run it in a 2×4 or 2×6 wall?

To install an HVAC system in a 2×4 or 2×6 wall, first, you need to estimate the right size of the ductwork, then outline the duct and wall design, drill holes, install the vent flue, set the equipment, put the plenum, install the return duct on either side and seal the open areas. 

It would be best to follow a detailed step-by-step guide for installing an HVAC duct in a 2×4 or 2×6 wall. The purpose of this article is to explain everything about the steps of installing an HVAC duct. We shall also briefly share about HVAC and its parts. 

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What is an HVAC duct?

All of us want to include proper ventilation in our houses. 

Installing an HVAC duct in the 2×4 or 2×6 walls will help to get adequate ventilation. 

But, everyone needs more for setting up an HVAC system in the house because the window and standing air conditioners can be quite bulky. 

The radiators can make a lot of noise, take up more room, and be dangerous for children. 

You must learn how to run the system if you have a 2×4 or 2×6 wall cavity. 

But before that, you should know about the HVAC system, its parts, and its functions. 

HVAC stands for heating, ventilation, and air conditioning that help regulate the closed area’s temperature, humidity, and purity. 

The HVAC duct is a cavity inside the wall that leads to the outdoors with metal tubes. 

These tubes can run through the houses and apartments to make every space comfortable with or without a window. 

Installing one should be done by a professional as it is quite a complicated job requiring proper knowledge. 

The ductwork should be between the studs and joints of the wall. 

It should have a clear route through the walls without any interruptions. 

Since it is quite complicated, leaving it to the professional is the best. 

Also read: What Size Duct Do I Need For A 12×12 Room?

How does the ductwork work?

The HVAC systems have heating and cooling coils to regulate and control the temperature of the surrounding air.

The system passes the air to the living areas with the help of a fan. 

When this happens, the duct takes the bad undesired air into the ductwork vents to make your surroundings comfortable and breathable. 

What are the different parts of the HVAC systems?

An HVAC system has a lot of parts, the following being the main parts:

  • The ducts – The ducts have a large trunk containing all the pipes to direct the cool or warm air to where it should go. 
  • Duct Transitions – The ductwork parts allow the pipes to flow through your house or building and enter all the desired areas. 
  • Flues – These are located half inside and outside the house or building. They must be well-insulation so that no air can get through the cracks. 
  • Plenum – It is a giant box stored with air and is connected to all other ductwork. Most systems have two boxes – one pushes the air out to the building, and the other is a return plenum that takes inside the undesired air. 
  • Drain pans – The HVAC systems use water to cool or heat the air, based on the system. These pans catch the excess water to avoid leakage through the walls. 
  • Drain lines – The drain lines direct the excess water to the drain pans. Otherwise, the water will seep through the walls. 
  • Refrigerant lines – These lines draw the refrigerant into the compressors, which further helps the HVAC system to cool or heat the air. 
  • Air handler – The handler is where the heating and cooling coils are located with the blower fans. It moves the air throughout the ductwork and spreads it to the desired areas. The handler also contains an air filter to purify the air and make it breathable. 

How do you run the HVAC duct in a 2×4 or 2×6 wall?

Everyone wants to have an HVAC system in the house for proper ventilation. 

If you have a 2×4 or 2×6 wall, you may want to know how to install it. 

Suppose you have experience in construction and knowledge about the installation. 

In that case, you can do it by the steps I will share. 

Otherwise, please leave it to the professional. 

Installation requires time and knowledge and can be complicated. 

Here is a brief about the installation of the HVAC system:

  • Outline the design for the duct in your wall. 
  • Mark the design on the wall. 
  • Drill out holes.
  • Install the b-vent flue.
  • Set the indoor equipment.
  • Put up the plenum.
  • Install the return ducts.
  • Seal all the areas that need to be covered. 

It is just a brief about the installation. 

We will share a detailed step guide if you want to do it yourself. 

Step-by-step guide on running an HVAC duct in 2×4 or 2×6 walls

I still recommend leaving it to the professional. 

But, if you insist on doing it yourself, here is a step-by-step guide to run the duct in the walls. 

The steps are applicable for both 2×4 and 2×6 walls. 

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Step 1: Outline the designs 

First, you need to plan and outline the duct structure for your wall size, i.e., 2×4 or 2×6. 

If you do not know how to outline, you can ask an experienced person to help you out and design the map. 

Ensure that the outline is appropriate enough for the duct dimensions. 

Step 2: Mark the designs on the wall

Once you have mapped the design, you need to mark the designs on your wall throughout every room. 

You should also mark the return locations of the wall and supply register areas on the floor.

The supplies must be around 8 inches from the walls to allow enough clearance for the doors and the curtains.

It will help cut the holes around ¼th inches in diameter for enough room for future registers. 

Step 3: Prepare and drill holes in your wall

Cut the returns straight down through the wall cavities and overcut the front edge around ¾th inches. 

It will help with proper airflow. 

The grille should be larger than the opening moving down through the wall cavity. 

If the walls are around 3.5 inches deep, the grille must be 6 to 8 inches tall. 

This height will help the sound of air to keep moving through the grille at a minimum level. 

Make sure you avoid cutting into the floor joists. 

You can check out this grille:

●     14 “w X 20 “h Steel Return Air Grilles – Sidewall and Ceiling – HVAC Duct Cover 

Step 4: Install the B-vent (double wall) flue.

Before covering the wall, you should put the B-vent flue first. 

It will help avoid the difficulty of installation. 

Double-wall or B-vent flue pipe will need at least 1-inch clearance to the combustibles. 

Everything entering the floor and roof should be overcut to adjust to this need. 

Use a sheet metal firestop to balance the flue, give enough clearance, and close the overcut holes.

The flat sheet metal with the round hole will complement the flue diameter and work better. 

Step 5: Set the indoor equipment

Suppose your home has any mechanical room in your basement located at the center. 

In that case, you need a furnace or air handling unit to properly allow area for installing the return airdrop at one side of the unit. 

Also, set up the evaporator coil on the top of the furnace if your system has any central air conditioning. 

A cased coil would be great and is accessible for future services. 

You should also have an uncased coil in the supply plenum to ensure that the air shifts through the coil. 

Give the refrigeration lines tight-sealed penetrations. 

The servicing of the uncased coils can be challenging, especially if you want the best from it. 

Step 6: Put the plenum.

Installing the plenum is a complicated part. 

A plenum gives purified air to the main areas of your house. 

So, it is up to you to install it either with the evaporator coil or in the air handler. 

You can also modify the plenum by cutting it 1-inch below the ceiling. After that, please attach it to your duct’s front and end and position it well. 

First, arrange everything on the floor and then attach them to the wall. 

Fix the supplies in the S-cleats at the starting and ending of the joints and connect them through drives. 

It would be best to have a subordinated duct to connect the top of the main box. You can design the point where you connect it to the main box. 

Repeat the same process on each side until you attach all the supplies to the HVAC unit. 

Step 7: Install the return ducts, which you can place on either side

Here, you must place the return ducts, which you can attach on either side. 

Put the return airdrop situated vertically beside the handler. 

The reason behind having the return airdrop is to attach them with the air handler and fan.

Step 8: Seal the areas that require covering

Now, it is time to seal all the uncovered areas. 

The step is quite important because it won’t give a perfect finish to the structure, but it will prevent the gathering of dust and debris.

Before you seal everything, consider going through everything to ensure the installation process is correct. 

If something is wrong and you seal it without checking, you cannot unseal it to solve any issues on the structure. 

Try this sealant:

Tips for maintaining the HVAC duct

If you want the duct system to last longer and maintain proper ventilation, you must clean it regularly. 

Some seals and joints can become loose, for which the system will release some vibrations. These vibrations can misplace the position of the ducts. 

The dust and debris can damage the entire system. 

So, here are some tips which you must follow to increase the lifespan of your duct system. 

Check and seal the leaks in the ducts

If there is any leakage in the duct, the house will lose around 10 to 30% of well-conditioned air. 

As a result, the energy gets consumed for nothing, and energy efficiency still needs to be achieved. 

The vents and return vents should be free from obstacles

Furniture remaining in front of the vents can block and disrupt the airflow and stop it from getting circulated throughout the desired areas. 

It can also affect the entire ductwork arrangement and result in fan motor burnout or altering pressure in the system. 

Insulate the ductwork

If you want the air passing through the ducts to remain at the proper temperature until it spreads to every corner of the house, you must insulate the ductwork. 

Hire a NADCA-Certified Air Duct Cleaning Professional 

You need to hire a professional to clean the air duct to keep the entire duct system. 

It is better to hire a NADCA-certified professional for the best services. 

NADCA stands for National Air Duct Cleaners Association. 

Put a UV light in the ductwork

Installing an ultraviolet light in the ductwork will sterilize the air and destroy bacteria and mold. 

The light will also prevent the build-up of molds and fungi inside the ducts, where the humidity sometimes can be pretty high. 

The most important role of light is to improve indoor air quality.

Test the ducts

Hire professionals for this step. They can take the readings of the air pressure in the ducts during the operation, find the amount of air loss, and ensure the system is free from damage. 

They will also be able to suggest some guidance about the ways to improve the ductwork arrangement. 

Keep the vents of the room open

Never think of closing the vents of every room to reduce the HVAC costs. 

Doing such things will not save energy bills. 

Instead, it will carry more air from the outside to be conditioned with the help of the return vents.

The vents will get blocked, and the same problem will occur when the vents get blocked by furniture. 

Ask your professional to install a zoning system if you wish to control the cooling and heating system in every room of your house. 

Final thoughts

Running an HVAC duct in the 2×4 or 2×6 wall takes work. 

It is better to let professionals do it if you do not have any experience with it. 

But, if you know the installation and construction, you can do it yourself. 

Also, follow the step guides to make sure everything goes perfectly.

Once you have installed the HVAC system, you must follow the aftercare tips to keep your HVAC system safe and increase its lifespan. 

Installing the HVAC system will improve the ventilation of your house, prevent suffocation, and purify the breathing air.

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How often should I change the ductwork?

The ductwork and HVAC systems last longer if you can maintain them properly. 

You can change the filters every 3 months for purified air. 

That should help your system last for at least 10 to 15 years. 

Can I install the HVAC system myself?

You can do it yourself, provided you have proper knowledge about it, and you have experience in the construction and proper installation.

Otherwise, it is better to leave it to experienced and certified professionals. 

Reference: HVACDuct Flow, ScienceDirect Research Paper, HVAC System ResearchFlorida’s Premier Energy Research Cente.

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Arthur Smith

Howdy! I am Arthur Smith, an electrical engineer who is extremely passionate about electronics. I have lived in different parts of the US and currently reside in Wisconsin. I am one of those rare children who knew what he wanted to study and do in life right from the start. I was a curious child who wanted to know how switches work and how the AC works, and I would always observe my dad whenever he would handle the wires and fix things around the house. I currently work as an electrical engineer at a reputed company and write for this blog. And I read loads of books or play video games in my free time.

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