How To Cap Off An Air Duct

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The air duct serves as the passage for the hot and cool air around your home. It filters the air that passes through by converting air into hot or cold depending on the destination. If you want to block a particular duct, you can put an end cap on it. We asked HVAC experts regarding air ducts and how you can maintain these. We'll gladly share with you what we learned.

Hardware stores carry end caps, or you can fabricate a cap for your air duct yourself. Use a metal sheet and cut it according to the size of the duct, allowing at least one inch in excess for the edge. Once you have the cap, you just put it on the air duct.

If you are interested in improving the air duct in your home, then this post is for you. Keep on reading to get more information.

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The Role Of Air Duct In Your Home

The air duct network in your home serves as the passage of air to the different areas through vents. The air that may come out from the vent may be heated or cooled, depending on the kind of vent it comes out.

If the vent releases cold air in the room, then the hot air is sucked through the return vet. Consequently, if hot air is introduced in the room, then cold air goes back to the duct.

Ducted heat recovery ventilation system with recuperation

What Are The Materials Needed To Cap Off The Air Duct?

Some homeowners prefer to put a cap in their air duct to close it off. There are some manufacturers of a duct end cap. These are available in various sizes and are made of galvanized steel. You can also find duct caps made of PVC and spiral ducting.

Check out this end cap on Amazon.

In case you want to make your end cap, here are the materials you would need:

  • metal sheet
  • tin snip
  • scribing tool
  • sheet metal folder
  • folding bars
  • s-lock

Capping Off The Air Duct

Ventilation system installation and repair service. hvac technician at work

Now that you have the materials ready, get the air duct's measurement. If you have a standard rectangular air duct, you should give an additional one inch to the metal sheet when you cut it.

In the metal sheet, mark the extra one inch. Next, cut the four corners of the metal sheet. Do not cut in right angles. Instead, you should cut sideways so that the folded parts do not hit one another.

When you fold the two shorter ends, do it only halfway. This will be the drive edge. You will use this site later on when you install the end cap. Use the folding bars to help you form the metal sheet properly.

Meanwhile, for the longer side, fold these at 90-degree angles. You should also create two drives for the end cap since this will be attached to the duct.

Attach the s-lock on the air duct since you will use this to close the duct. Then you put the end cap on the air duct.

Finally, contractors recommend that you put a duct sealant to prevent air leaks. Applying a sealant is especially useful for round-end caps. You will save on utility costs and increase efficiency when you put a sealant.

Find this duct sealant on Amazon. 

Is It Important To Clean Air Ducts?

According to the Environment Protection Agency [EPA], it may not be necessary to have the ducts cleaned. Although this concern about air ducts is generally a novel question, initial studies show that not cleaning the air ducts does not make much difference.

Of course, the exception to the rule is when molds and vermin are growing inside the duct system. You should also clean the ducts when family members have illnesses or allergies that may be due to the home environment.

If you decide to have the air ducts cleaned, you could hire a professional. But you need to understand their procedure and cleaning products used. EPA also suggests that you interview at least three service providers to compare costs and services. These companies should also be able to explain to you why they arrive at such a cost.

You can also ask friends or family for referrals. Or you can consult a directory to see which company is a good fit for you.

Check out this article for more information about closing the HVAC duct.

Should You Close Air Vents?

Earlier, we mentioned that air vents are part of the air duct system. This part is where the heated or cooled air comes out. But what if you don't want to use the functional air vent anymore?

Contractors say that you should not close the vent even if you are not using it. For one, you will prevent the flow of air. It might lead to the freezing of coils. When this happens, you'll have to replace the damaged part.

It's also possible that the system will lose its efficiency. Even if you close the vents, the air will attempt to come out through the registers and in an even greater force. You will overwork the system when this happens instead of sending more air to the room where you need it the most.

This also means that you should not close the floor vents. Make sure that you don't cover these vents with carpet, rugs, or any furniture.

Check out this article for more information about HVAC vents.

How To Close The Air Vent Permanently

When the time comes that one of your air vents is no longer serving its purpose, what can you do about it? First, you must identify if the vent you want to seal off is a supply or return vent. The return vent is the one that receives the unwanted air from the room. You should not close the return vent under any circumstances.

You can seal off the vent permanently if it is no longer in use. This happens when you reconfigure the ductwork, and that particular vent no longer has access to any air. For this unused vent, you can put drywall on the opening. Put tape on it and some texture to cover up any gap. Then finish it off by painting it with the same shade as your wall.

Tips To Clean The Air Vent

Lint being removed with a brush from a dryer vent

If you want to have clean air around the house, make it a habit to clean air vents. You also get to save some money because the vents are functioning properly. There is no need to augment the heat or cold available in your room.

Prepare the following materials:

  • Vacuum cleaner
  • Screwdriver
  • Brush with strong bristles
  • Broom
  • Face mask

To begin cleaning, turn off the power source of the vent. Then remove the screws from the air duct cover or grille. Use a brush to remove the dust in the grates. You can also try putting the grille in the bucket with soap and water.

Include the grilles in the ceiling when you remove the dust. The broom will come in handy as you work on removing the dust.

The next step is to use the vacuum cleaner through the ducts. You will need heavy-duty equipment, so you might consider renting one. You will need a long hose to reach as much as possible through the duct. Don't forget to wear a face mask as you work, especially if the duct is full of dust.

But if you want a more thorough cleaning of the air duct, you could hire a professional cleaner. Once again, you could ask for referrals or consult a cleaning services directory.

Final Thoughts

Residential HVAC Duct Cleaning with a Power Brush

Ductwork plays an essential role in your home because it distributes clean air in areas where these are needed the most. The air duct serves as a passage for the air. Whether hot or cold, the treated air comes out through the supply vent. Meanwhile, the unwanted air goes back through the return vent.

If you want to close a specific portion in the air duct, you can put an end cap on it. The end cap is made chiefly of galvanized steel, but it is also available as PVC. You can buy these caps at hardware stores or fabricate your own. Once you have the end cap, you can attach it to the air duct. Don't forget to seal the cap to prevent air from escaping.

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