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How To Replace Ductwork Between Floors In 3 Simple Steps!

There can be various issues HVAC contractors encounter while replacing ductwork in between floors. Ducts must be in good condition and have all necessary fittings. That is why you must replace them on a regular basis.

Now, you might want to know: how to replace ductwork between floors?

The procedure is not too hard. You just need to follow a few steps. First of all, you might need to add a false return grill. You have to cut a hole through the floor after peeling off the carpet. And finally, you have to reinstall the ductwork.

Seems quite easy, doesn’t it? We’re sure you’ll not change your mind at the end of this article. This article explains every detail on how to replace ductwork between floors.

So, without wasting time, let’s try to fix this.

When Should You Replace Your Ductwork?

It’s critical to explore the most straightforward methods for determining when new ducting should be installed. If something is amiss with your ducts, they will offer you hints. Knowing what to look for, smell for, listen for, and even feel for is crucial.

The following are some of the most prevalent indicators that your ducting needs to be updated-

Your Home Is Dusty

If your home is particularly dusty these days, it’s conceivable that your ducts have cracks or gaps. Or, they are not properly sealed. Dust from outside the ductwork goes inside, travels through the ducts. And ends up in your home when this happens.

Inconsistent Temperature

Have you ever noticed that one portion of your house is significantly hotter or cooler than others? This could signal a leak in your HVAC ductwork. This happens more in the case of basement floors. If that’s the case, you’ll have to insulate ductwork there.

For any of the above causes, you need to replace your ductwork. Otherwise, as said before, the overall efficiency of HVAC might be hindered.

Funny Smell

There’s a risk your ducts are moldy if you notice a strange odor coming from them. Condensation can happen when warm, moist air passes through chilly ductwork.

Noisy HVAC Unit

Your HVAC system should be rather quiet. It could be a clue that your ducts are too small if it feels noisy to you. Or, they are imbalanced for your system.

You can see how important it is to take care of your ductwork. Otherwise, you might be indulged in various problems. Like dripping water from your basement ductwork. So, don’t be careless about these small steps.

Replacing Ductwork Between Floors- 3 Steps

DIY ductwork repairs may be difficult. This is due to the ductwork’s vast distribution throughout your home. It’s a sensitive system, too.

You risk damaging your HVAC system if new ductwork is not changed and fitted appropriately. The total efficiency of HVAC may be hampered if they are not balanced and insulated adequately. So let’s have a look at what we can do about it..

Tools Required

You’ll require a few tools while carrying out the procedures –

  • Air grille
  • Drill machine
  • Duct sealant
  • Carpet kicker

If you gathered all the tools, let’s dive into the procedure.

Step 1 of 3:  Adding A False Return Grill

To obtain access to the ducts, cut an access hole in the ceiling of the first level in a central position. The ¼-in. x 24-in. duct is the most popular size. This size is just big enough to fit between the joints of most floors. Most installers claim that this access hole can reach a 100 sq. ft. area.

Install a ¼-in. x 24-in. return air grille with a piece of flat black sheet metal. Connect it to the back of the grille once the job is finished. There will be no duct attached. Instead, there will be a return grille that doubles as an access door. 

It will vanish when the resident gets used to it in approximately a week. It can be easily removed in the future to run phone lines or computer wires.

Install faux grilles behind an adjacent wall or in the next room if extra access is required. So they will not all be visible from one location.

Step 2 of 3: Pull The Carpet Back

Under most carpets, only plywood or particle boards are placed. Peel the carpet and cut through the plywood to gain access to the duct between the floors.

This is easier than removing water from a carpet. Tack strips along the room’s edge hold most carpet in place. As the carpet is stretched onto the tack strip, little spikes hold it in place. The carpet’s edge has a ½ inch lip. It is tucked beneath the wood trim at the bottom of the wall.

Pull up the carpet’s edge at the room’s corner with a pair of pliers. Continue pulling, and the carpet will readily peel back. Then carefully remove the padding, which is generally attached with staples every four feet on center. This is how you’ll reveal the plywood.

With a skill saw, cut an access hole through the plywood. Cut where the plywood is nailed down on the joists. Remove the plywood and follow the next step to install the duct system.

Step 3 of 3: Installing The Duct

This part is quite easy. Proceed to the location where the boot will be placed beneath the subfloor. Bend each of the four boot tabs out 90 degrees to attach them to the subfloor bottom. Check to see if the boot is centered over the hole. Also, ensure if the tabs are flush with the subfloor.

Connect the drill to a ¼ inch hex bit. Into the subfloor, drive two self-tapping ¾ -inch screws through each tab. This is to keep the boot opening from falling into the hole you made. However, we want you to be careful while using the drill machine.

To properly seal the area and prevent leaks, apply duct sealant. To any cracks or small holes, this comes in a tube or a barrel.

Finally, proceed to the room indicated by the boot. The base of the floor register should be slid into the hole. Press it down until the register’s outer flanges are flush with the finished floor. 

If the floor duct arrives with fasteners, use them to secure it to the floor. Otherwise, it’ll just sit there in the gap. To get the carpet back on the tack strip, use a carpet kicker.

If you don’t know where to look for a carpet-kicker, here are some of our best picks-

Product 1
Product 2

These products are durable and surely will not fail you.

This was everything you needed to know about ductwork replacement. The steps should be quite easy to pull off. 


Question: What’s the cost of replacing ductwork?

Answer: Replacing ductwork might cost you about 5000$-6000$. For extreme cases, it might cost you around 10,000$. But it will surely not cost you more than that.

Question: After how long should I replace my ductwork?

Answer: Usually you won’t have to replace your ductwork for 15-20 years if you find no problem. In some houses, you don’t need to replace them for 35+ years. 

Question: How long will it require to replace ductwork?

Answer: Usually it takes around 3 days to finish replacing your ductwork. One day for the change and two days for ducting. 


Now you know how to replace ductwork between floors. We hope you didn’t change your mind and found it quite easy. 

But if you faced any issues while following these steps, let us know.

Good luck with the ductwork!