Can You Use Flex Duct on a Range Hood Vent? (The Truth)

If you're in the middle of a range hood installation, you might be tempted to use a flexible ducting for your vents. But is it the best choice for a range hood?

Flex ducting may seem like a quick and simple solution when installing a range hood, but is it the correct type of ductwork for kitchen ventilation?

In this blog post, we’ll discuss the pros and cons of using flex ducting for range hoods and whether or not it’s the best choice. We’ll also provide a few tips on choosing the right flex ducting for your range hood installation and some helpful tips on installing a range hood. So whether you’re in the middle of a range hood installation or just looking to improve your ventilation system in general, read on!

No. Try not to use flexible ducting for your vent hood ventilation. This type of ventilation increases the drag and might easily result in back-drafting. It can also get pinched or muffled and restrict airflow. Use rigid ductwork instead.

Image of flex ductwork tube. Source: adobe stock
Image of flex ductwork tube. Source: Adobe Stock

What is a flex duct

Flexible ducts are bendable tubes with ridges. Flexible ducting can be used in tight spaces, cabinets, and non-standard layouts, and it can be used for many different things. Insulated and non-insulated flexible ducting are both commercially available. Common materials include polyvinyl chloride (PVC), silicone, rubber, polyurethane (PU), and aluminum.

If you are looking for some fex ducting, check out some of these options here.

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There are several reasons to choose flexible ducting:

  • The small diameter of this ducting makes it a good choice for use in places where space is at a premium, such as in cabinets, ventilation ducts, and wall cavities.
  • Installing flexible ducting takes less time and effort than installing rigid ductwork, and once it’s in place, it’s simpler to make modifications.
  • The flex duct may be checked for obstructions with transparent ductwork, which is available.
  • Flexible ducting is convenient for short duct lines due to the material’s adaptability.
  • It’s compatible with rigid ductwork systems, allowing for the connection of outlets and vents.
  • It can serve as temporary ducting.


The trade-off between adaptability and ease of use is durability. Unlike its rigid ducting, flexible ducting is easy to tear and may leak. Therefore, it’s important to keep an eye out for blockages and other symptoms of damaged ducting since they might reduce the performance of the extraction system and cause downtime.

  • As a rule, flexible ducting can’t be installed outside the building.
  • The noise level in a building may increase when flexible ducts are used instead of stiff ones.
My favorite range hood (at the moment):

COSMO COS-63190S Wall Mount Range Hood

Can you use flex duct on a range hood vent? (the truth) | 71ddmbmvgwl. Ac sl1500 | range hood homeland
My favorite range hood (at the moment):

COSMO COS-63190S Wall Mount Range Hood

This is one of the best hoods available at this price point. Reasonably strong CFM for the cost, and it has received rave reviews (over 3,800 reviews!). It looks great, and the LED lights provide a pleasant brightness. For the price, its performance and style are outstanding. Highly recommended!

Can I use a flexible duct for my range hood?

We advise against connecting your range hood to a flexible duct. Flex duct is not ideal since they can accumulate dirt and odors.

Can I use a semi-rigid duct for my range hood?

Even though a semi-rigid duct lasts longer than a flex duct, a rigid duct is still the superior choice for your range hood. When comparing rigid and flexible ducts, rigid is more durable because it is made from better materials.

What is the minimum duct size for a range hood?

A range hood requires at least a 4-inch duct. This sized duct works well with low CFM hoods in large box retailers. The standard duct size for a range hood is 6″ to 8″. However, bigger duct sizes may be needed for more powerful outdoor or commercial range hoods.

If you want even more tips and insights, watch this video called “Ducting Do’s and Dont’s for Vent A Hoods –” from the Erik Bergstrom YouTube Channel.

This video called “Ducting Do’s and Dont’s for Vent A Hoods –” from the Erik Bergstrom YouTube Channel.

Frequently asked questions (FAQ)

Do you still have questions? Below are some of the most commonly asked questions about using a flex duct on a range hood.

Does a range hood uses 4-inch ductwork?

Of course, the duct’s dimensions will be determined by the range hood’s cubic feet per minute (CFM). Most range hoods need at least a 6-inch duct, and a 4-inch duct is too small. Only hoods with a CFM rating of 400 or less should use this.

A duct size of 6″ is suggested for hoods with 600 CFM, 8″ for 900 CFM, and 10″ for 1200 CFM.

Why is it necessary for a range hood to include a transition duct?

A range hood transition duct is a flexible piece of ductwork that may be cut or spliced together to change the duct’s internal diameter. For example, if you already have a 4″ duct but need to upgrade to a 6″ one, you may do it with the help of a duct transition adapter.

Due to the negative impact on the hood’s performance, a poorly executed duct transition is essential. Using a duct of the correct size is very crucial. Don’t utilize a duct that isn’t at least as large as our minimum dimensions!

Can I run my range hood ductwork up into the ceiling?

No. The attic should not be contaminated by cooking smoke, oil, grime, or chemicals. It’s better if you could get rid of it completely. Building up dust and chemicals in the attic is bad for your health and your house. Your hood must be vented outside your house and never into the attic, walls, or between levels.


An effective range hood may help you save time and energy while cooking and remove any grease or oil residue from your food. If you’re considering acquiring one, make sure it has high-quality ductwork. In particular, a flexible duct shouldn’t be used for the hood’s ventilation. It does a poor job of keeping the stovetop clean. As a result of its rough interior, this material may serve as a trap for the chemicals. If you want to avoid making a mistake when installing your range hood, opt for a rigid duct.

This article covered flex ducts and the pros and cons of flex ducting for range hoods. Here are some key takeaways:

Key takeaways

  • Flexible ducts are bendable tubes with ridges.
  • Always hire a professional contractor or HVAC expert to install your ductwork
  • Ducts serving the range hood need to be airtight, equipped with a backdraft damper and should have smooth inner surfaces.
  • Flexible ducting is appropriate for usage in tight areas, cabinets, and non-standard layouts and has various uses. 
  • The small diameter of this ducting makes it a good choice for use in places where space is at a premium, such as in cabinets, ventilation ducts, and wall cavities.
  • A range hood requires at least a 4-inch duct.

So, do you use a flex duct on a range hood? And did I cover everything you wanted to know? Let me know in the comments section below (I read and reply to every comment). If you found this article helpful, check out my full blog for more tips and tricks in your kitchen. Thanks for reading, and stay fixed.

Helpful resources

Image Of Roger Harris
Written by Roger Harris, Staff Writer

Hey there! My name is Roger, and I've been selling range hoods for over six years. I now run this blog all about range hoods and kitchen ventilation! If you're looking for a new range hood for your kitchen, this is the place for you.

Yerain Abreu
Edited by Yerain Abreu, Staff Editor

Yerain is our staff editor and co-founder. He has a passion for writing, editing, and website development. His expertise lies in shaping content with precision and managing digital spaces with a keen eye for detail.

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