How Does A Ductless Range Hood Work? (*2021 Guide*)

Do you want to know how a ductless range hood works?

Ductless range hoods are very similar to their ducted cousins, there are just a few key differences between the two.

In this guide, I will go over...

  • How ductless range hoods work
  • Why changing the charcoal filter is crucial to health
  • The installation differences between ductless and ducted

Let's get started with this guide!

how does a ductless range hood work (1)

How Does A Ductless Range Hood Work?

A recirculating range hood works pretty much the exact same way as a ducted range hood.

The main difference is that instead of the air getting exhausted to the outside, it passes through a filter, and then recirculated back into the home.

The exhaust vents are usually at the top of the range hood or on the side, and when you turn on the range hood, you will be able to feel the air exhausted back into the room.

Most people don't realize that almost all ducted range hoods can be converted into being used as ductless --- all you have to do is purchase a filter that includes a charcoal layer.

Read Also: What Are The Best Ductless Range Hoods?

The Charcoal Filter

The activated charcoal layer greatly helps reduce odors and harmful particles that are usually expelled to the outside.

Frequently, there is also a felt-like layer or paper layer that helps trap smoke.

Almost all ductless range hood filters have this charcoal layer that is covered by an inner and outer layer of aluminum mesh. The aluminum mesh layers also helps catch grease and gives the filter some rigidity.

ductless range hood (charcoal filter)

Charcoal Filter For Ductless Range Hoods

Read Also: How Many CFM Do I Need For My Range Hood?

Change The Charcoal Filter Frequently

The primary maintenance item with ventless range hoods is changing the filter.

Changing out the ductless charcoal filter is recommended once every three months. Personally, I recommend changing the filter once a month if you cook everyday --- it is an individual preference.

You also may want to change the filter every month if you are sensitive to poor air quality.

These filters usually cost in the $10 to $20 range.

With ducted range hoods, the filter only needs to be changed once a year --- if at all --- because usually you can just clean the mesh filter or metal baffle filters. These filters can be cleaned with a simple detergent.

Read Also: What Are The Quietest Bathroom Exhaust Fans?

Installing A Recirculating Range Hood

When you install a ducted range hood, there are two round or square cutouts, one at the top and one in the rear.

These cutouts are removed depending on whether you want to have a vertical duct to the roof, or a rear duct to the wall.

Of course, if you want to use the range hood as ductless, then you simply keep the cutouts in tact.

The installation is significantly simpler than having to install a duct to the outside or even just having to reconnect the duct. The basic installation procedure is to screw the range hood to the wall studs and hook up the electrical wiring or plug it in.

You don't have to worry about the wall duct, the exterior vent cover, and possibly even going on the roof.

One common problem with ducts is that it creates a wall penetration that can allow in exterior air and animals. I have frequently found birds nests in vents which is one reason that there is a flapper.

Read Also: How To Vent A Bathroom Fan Into An Attic?

How Does A Ductless Range Hood Compare To Ducted?

I don't think there is any doubt that ducted range hoods are better that non-vented range hoods.

There just isn't way to compete with a range hood that exhausts all of the harmful pollutants to the exterior --- a filter will only go so far. Of course, sometimes you just cannot install a duct to the outside.

You may live in a condo where installing a duct would go into a neighbors condo. Or your range or oven may be in an interior wall location where it isn't feasible to duct to the outside.

Or you may just not want to deal with the expense and hassle of ducting the range hood to the exterior. I would say that around 75% of homes that inspect have recirculating range hoods --- so its pretty common. A non-vented range hood will still do the job, and it is light years ahead of having no range hood.

Save Energy

In addition, there are energy saving considerations when installing a ductless range hood. If you duct the exhaust to the outside, it is also expelling expensive conditioned air to the exterior --- almost equivalent to having an open window.

From an energy saving perspective, a ductless range hood definitely beats the ducted.

Read Also: What Are The Best Bathroom Exhaust Fans With Humidity Sensors?

ductless range hood (charcoal filter)

Homeowner Neglect

The biggest problem I find with ductless range hoods is that homeowners neglect to replace the filter.

As a home inspector, it is extremely common for me to put in my inspection report that the filter needs to be changed. I want to let my clients know up front that this is something important to do regularly in order to keep their indoor air quality high.

Frequently, the filter is also missing the charcoal layer.

The Bottom Line

I think installing a recirculating range hood is a great way to add value to a kitchen.

Personally, there is no way I would live in a home without a range hood... period. Perhaps if you don't cook, then it doesn't matter --- and opening a window shouldn't be relied on. Always having a window open also greatly reduces the energy efficiency of a home.

And even though ventless range hoods aren't as good as their ducted cousins --- they still get the job done and keep the air reasonably clean.

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7 thoughts on “How Does A Ductless Range Hood Work? (*2021 Guide*)”

    • Hi Elain,

      Technically, you could, though it would be against manufacturer recommendations. If the range hood is properly ducted, and has adequate CFM (suction), there is no need for a charcoal filter.


  1. Hi Arie – I have the same questions as David. I’m looking at a similar Cosmo in a 36-inch width. Does the air recirculate though the cabinet above and if so does that mean the doors need to be open when circulating? Also, can I still use the cabinet above for storage or will things get greasy? Appreciate all the great advice!

    • Hey Scott,

      Apparently with the Cosmo units it still needs to go through the cabinet to be vented in a ductless install which is a poor design. It will impede air flow if you keep the upper cabinet closed. And no, definitely don’t store anything in the cabinet if it is vented into it.


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Arie Van Tuijl

Arie Van Tuijl

I am a licensed home inspector in two U.S. states and the founder of Home Inspector Secrets. After performing hundreds of inspections, and seeing thousands of house defects, I realized people would love to have an online resource dedicated to home maintenance. I write detailed home guides and product reviews sprinkled with inspection tips. You can read my bio here.

About Home Inspector Secrets

Home Inspector Secrets is an online resource for owners, buyers, and sellers to understand all aspects of home maintenance. We have detailed home guides, product reviews, inspection advice, and much more.

Other Home Guides

Looking to learn more about home maintenance? Check out our other informative home product reviews and guides!