A recirculating range hood works in exactly the same way as a ducted range hood.
The main difference is that instead of the air being exhausted outside, it passes through a filter and then returns to the house.
The exhaust vents are usually on the top or side of the range hood and when you open the range hood,
you will be able to feel the air being exhausted when you come back home.
Most people don’t realize that almost all ducted range hoods can be used as ductless—all you need to
do is buy a filter that includes a charcoal layer.
The activated charcoal layer helps reduce odors and harmful particles that would normally be expelled outdoors.
Often, there is a felt-like layer that helps trap smoke.
Almost all ductless range hood filters have this layer of charcoal covered by an inner and outer layer of aluminum mesh. The layers of aluminum mesh also help trap grease and give the filter some rigidity.
Change the charcoal filter frequently
Many other basic maintenance items including ventless range hoods are changing filters.
It is recommended to change the ductless charcoal filter at least once every three months. Personally, I recommend changing the filter once a month if you cook daily—it’s a personal choice.
If you are sensitive to poor air quality, you may want to change the filter every month, so this is also a personal choice.
These filters are usually priced in the $10 to $20 range.
With ducted range hoods, the filter should be changed at least once a year
— if not more — because you can usually clean mesh filters or metal baffle filters easily. These filters can be cleaned thoroughly with a normal detergent.
Installing a recirculating range hood
When you install a ducted range hood, there are two circular or square cutouts, one on the top and one on the back.
Depending on whether you want a vertical duct on the roof or a duct behind the wall, these cutouts are moved in sequence.
Of course, if you want to use the range hood as ductless, you just have to keep the cutouts in tact.
Installation is significantly easier than installing a duct to the outside or even reconnecting the duct.
The basic installation method is to screw the range hood into the wall studs and hook up or plug in the electrical wiring.
You don’t have to worry about wall ducts, exterior vent covers, and possibly roof vents at all.
A common problem with ducts is that they create a wall penetration that can allow outside air and animals in. I often find bird nests in the vents which is one reason to have a flapper.
How does a ductless range hood compare to ducted?
I don’t think there’s any doubt that non-vented range hoods are better quality than non-vented range hoods.
There’s no way to compete with a range hood that exhausts all harmful outdoor pollutants—a filter will only go so far. Of course, sometimes you can’t install a duct from the outside.
You may live in a condo that has a duct installed capable of going to a neighbor’s condo. Or your range or oven may be located on an interior wall where ducting to the outside is not possible.
Or you don’t want to deal with the expense and hassle of ducting an external range hood. My opinion is that about 75% of the homes I visit have recirculating range hoods—so this is pretty common. A non-vented range hood will still do the job and is years ahead of having no range hood at all.
Additionally, there are some energy savings to consider when installing a ductless range hood.
If you duct the exhaust to the outside, it is expelling expensive controlled air to the outside—equivalent to having an open window.
From an energy saving perspective, a ductless range hood clearly beats ducted.
The biggest problem I’ve found with ductless range hoods is that homeowners neglect to replace the filter far too often.
As a home inspector, it is very common for me to mention that the filter needs to be changed in my inspection report.
I like to convey to my clients that it is important to do this regularly to keep their indoor air quality healthy.
Often, the filter is also missing the charcoal layer.
I think installing a recirculating range hood is a great way to add value to your kitchen.
Personally, I’d say there’s no way to live in a house without a range hood…period. Perhaps if you don’t cook, it doesn’t matter to you—and shouldn’t be relied upon to open a window. Having a window open all the time can greatly reduce the energy efficiency of a home.
And while ventless range hoods aren’t quite as good as their ducted cousins — they are now