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How To Seal Range Hood Vent – Step By Step Guide

Yes, we install range hoods in our kitchens to vent the stale air out through the duct hose. So, it is pretty crucial to seal the duct joints efficiently to prevent any leakage. Otherwise, all your money, time, and labor will go in vain. To let your hood best serve the purpose it is meant for, you better learn how to seal range hood vent.

If you want your exhaust fan to run smoothly, you make sure the greasy air stay inside the ductwork while passing through it to move outside. The only way to ensure it is to seal the duct seam airtight so that passing air cannot leak and come back to the kitchen.

That is what this article will guide you on how to seal range hood duct. Here you go with five simple steps to seal the duct and reap the max benefits from your kitchen fan.

These are really simple and easy methods to ensure leak proof air passing through the range hood ductwork. You can apply those without needing professional help.

Step 1: Attach the Duct hose to the Duct Transition

Attach the Duct hose to the Duct Transition

While installing the hood, you will join the flex or rigid duct to the duct transition coming with the hood. Make sure that here the joining goes right. There are two phases to accomplish accurately.

At first, put the duct transition to the back of the hood and a gasket between the transition piece frame and the hood base. In fact, this will make the transition piece firmly sit here. 

Now, you bring down the duct hose to the extent of joining the duct transition. They should stay stuck, and now you should apply aluminum tape covering the seam or where the two pieces meet. Make sure the aluminum tape firmly sticks to the joining surface, and no air bubble is left.

If you use a rigid duct hose, it should reach the duct transition to fit into. In case you go for a flex duct hose, you can extend it down so far you need to reach the duct transition.

Step 2: Use Aluminum Duct tape

When you join the duct hose and the transition piece, they should stay in place even without the duct taping. But this will not make the joining airtight. The aluminum duct tape is urgent to make the seam airtight so that no air can leak to come back in your kitchen.

Now, if you find the two tubular pipes do not hold as tight as they should, take help from an assistant or friend to hold the duct so that you can conveniently wrap the aluminum tape around the juncture.

Press the Duct and the tape tightly

Step 3: Press the Duct and the tape tightly

To make the taping airtight, press your hand firmly on the spot where the two meet and also all over the tape. Leave no air bubble or vacant space between the ductwork and the taping.

Step 4: Test whether the Duct Tape is Airtight

You should no way go laid-back in that phase because range hood is all about removing the stale air laden with moisture and contaminants to the outside. And if air leaks through any juncture or location, it will all go futile.

So, you must recheck whether the taping has been successful or not. To test this easily, you better run the range hood and feel if air is leaking through this spot. So, plug in the hood and switch the unit on to check the blower is working right or wrong.

Surf different speed settings and put your hands near the taping to feel any air passing. If you feel air seeping through the juncture, you need to go for even tighter sealing by putting a second layer of aluminum taping.

Step 5: Apply The Second Layer of Duct Tape

Do you feel air leaking from the joining of the transition piece and the duct hose? If yes, it is time to put a second layer of taping over the previous one. And you should repeat the same process to ensure efficient sealing to air. The best way to apply a second layer is to put the tape over the upper edge of the existing taping and secure it the most.

So, when you install a range hood, you should be very meticulous about ducting properly. In this stage, when you have successfully attached the duct hose and transition piece, you should not jump to the next step of putting the chimney covers. Rather, before placing the chimney covers, you should run the unit to check for any leakage.

How to prevent outside air or anything else from intruding the vent?

Leakages for air to go out may happen where the inner ductwork takes place. I mean, the spot where the duct hose and transition piece joins may leak air if the joining fails to seal air. We have already learned how to sort this issue out.

But air, tiny animals, leaves, and the likes may come in from outside through the outer ductwork as your range hood set-up has two ductworks or joining. What if your vent hose is intruded on by the said disturbances? 

To sort internal leakage, we have suggested one thing, and that is aluminum duct tape. In this case, when the issue is an intrusion, one friend is there to stand by your side – caulk.

However, the entire process is a bit broader needing you to go through a separate article on preventing outer intrusion in your vent hood. A damper can work to prevent unwanted entrance from outside the kitchen. So, how to seal a vent involves sealing both out letting from the inner and intrusion from outside.


That is how you can seal your vent hood and keep your kitchen free from greasy air and hot steam. So, picking a top-quality vent hood is merely half-done if you do not install the unit the way air is not coming back through leakages as you can sort it out simply, as is claimed in this article, learn how to seal range hood vent.

Make the duct joining airtight to keep the ghastly flow of the stale air to reach out of the kitchen as fast as possible. You don't want to encounter greasy substances and moisture in your cooking space.

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