Do Ductless Range Hoods Really Work?

On this page (11 sections)

1. Do ductless range hoods work for grease and odors?
2. What can a ductless range hood not do?
3. Does airflow drop in ductless mode?
4. How long does the charcoal filter keep working?
5. Does any charcoal filter fit any ductless hood?
6. Which cooking jobs suit a ductless hood?
7. Why does a ductless hood sometimes seem to stop working?
8. What should you check before you buy a ductless hood?
9. How do you get the most out of a ductless hood?
10. Which kitchens get the most from a ductless hood?
11. Decide whether ductless range hoods fit how you cook

Yes, a ductless range hood works for two jobs: catching cooking grease and reducing cooking odors. It does not do what a ducted hood does, which is send heat, steam and gases outside.

So whether ductless range hoods work for you depends on how you cook and how well you keep up the filters. The sections below sort what they do well from what they can't do.

For background on the parts, read what a ductless range hood is.

Do ductless range hoods work for grease and odors?

Yes, while the filters are clean. The metal grease filter catches oil, and the charcoal filter helps with cooking odors as the air passes through.

The air meets the grease filter first, so most of the oil is gone before it reaches the charcoal. CIARRA, for example, uses 5-layer aluminum mesh filters to trap cooking grease and oil.

Broan says the charcoal filter in its 413004 removes smoke and odors, and that the hood installs as non-ducted only with that filter. The result is less grease and fewer cooking smells in the room, which isn't the same as venting air outside.

What can a ductless range hood not do?

A ductless range hood can't remove heat, moisture or combustion gases, because the filtered air goes right back into the room. This table shows where the two hood types differ.

For more on that trade, read ductless vs ducted range hoods.

How well do ductless range hoods work on heat and steam?

They don't move either one out of the house. After a long session at the stove, the kitchen can feel warmer and damper than it would with a ducted hood.

What about gas ranges and frying?

A hood that vents outside is the stronger setup for a gas range and for frequent frying. Frying throws more grease and steam into the air, and a ducted hood sends that load outdoors instead of filtering it back.

If you cook on gas, read your range and hood manuals for ventilation advice, and ask a qualified pro if you're unsure about your setup.

The U.S. Department of Energy has general background on home ventilation.

Does airflow drop in ductless mode?

Often, yes, because the charcoal filter slows the air. SNDOAS rates its hood at up to 700 CFM and says that using its carbon filter reduces the hood's airflow.

So treat a printed CFM figure as a ducted number when you compare models. Between two ductless-capable hoods, the higher rating leaves more margin after the filter takes its share.

If a hood seems weaker than it used to, check the filters first, since a clogged or worn one cuts airflow.

How long does the charcoal filter keep working?

It works until it fills up, and then odor control fades. That is why makers give a replacement interval.

CIARRA says to replace its CACF006 filters every 2 to 4 months, or more often with heavy use. SNDOAS suggests about every 3 months, and gives 3 to 6 months for its CF-0475 depending on how often you cook.

For more on timing, see how long charcoal range hood filters last.

Does any charcoal filter fit any ductless hood?

No, filters fit by model number. SNDOAS says its CF-0475 is made for the US0475B, US0475BPB, US0475BTC and US0475A hoods and is not compatible with other brands or models.

SNDOAS names the CF-0475 for converting its 30 inch hood, so confirm that your model number appears in the filter's fit list.

The Broan-NuTone 41F is 8.75 x 10.5 x 0.375 inches, and its fit list names the 41000, 44000 and 45000 series among others.

Which cooking jobs suit a ductless hood?

Everyday cooking suits it best, because grease and odors are the two things it handles. Here is a rough way to match the job to the setup.

• Boiling, simmering and reheating. The fan can run low, and the grease filter has little to catch. Steam stays in the room, so crack a window if the kitchen gets damp.
• Pan cooking and sauteing. This is the job a ductless hood handles best, and CIARRA suggests medium speed for everyday cooking.
• Stir-frying and searing. CIARRA suggests high speed here. Expect more grease on the metal filters, so wash them more often.
• Deep frying and cooking on gas most days. Ducted is the stronger setup here, so a ducted or convertible hood is worth the extra work if you can run a duct.

Why does a ductless hood sometimes seem to stop working?

Almost always, it is the filters or the fit. These are the usual causes, roughly in the order to check them.

• A greasy metal filter. Heavy oil buildup chokes airflow, so wash it before you cook again. SNDOAS describes its baffle filters as dishwasher safe, but check your manual first.
• An old charcoal filter. It can look clean and still be spent, so go by the maker's interval.
• A loose filter. SNDOAS warns that a carbon filter that isn't locked in can loosen and make noise.
• A hood narrower than the cooktop. Outer burners sit outside its reach.
• A hood at the wrong height. Follow the mounting height in the manual.
• Expecting it to clear heat. A ductless hood never moves heat out of the room.

What should you check before you buy a ductless hood?

Check the filter it needs, its width and its noise level. Those three details decide how it feels day to day.

Match the hood width to the cooktop: a 30 inch cooktop pairs with a 30 inch hood, and a 36 inch cooktop with a 36 inch hood. Broan says its 413004 should sit at least 18 inches above the cooktop.

Noise comes in different units, so compare like with like. CIARRA gives up to 6.5 sones, while SNDOAS rates its hood at 66 dB.

Also check whether the hood can switch. Convertible models such as the CIARRA CAS75918A and SNDOAS's 30 inch hood run ducted or ductless, so you can start without a duct and add one later if your kitchen allows it.

How do you get the most out of a ductless hood?

Turn the fan on before the pan heats up, and pick the speed that matches the job. Starting early means the filters are already pulling air when the first burst of steam and grease arrives.

Then keep two dates: the next wash for the grease filters and the next swap for the charcoal filter. Wash the grease filters after a heavy frying session instead of waiting for a set date, and put the charcoal swap on your calendar.

Which kitchens get the most from a ductless hood?

Kitchens with no outside vent get the most from one, because it is built for that setup. Rentals, condos and older kitchens with no duct are the usual examples.

Renters usually can't cut a new vent through a wall, so a ductless hood may be the only practical upgrade. Plug-in models help here too: SNDOAS's 30 inch hood ships with a 3-prong plug and needs no additional hard wiring.

If your kitchen has no vent at all, see range hood options without a vent for the full list.

For buying advice, read the buying guide for no-vent kitchens, then compare models in the best recirculating range hoods roundup.

Decide whether ductless range hoods fit how you cook

A ductless range hood works well in a kitchen with no duct, everyday cooking and filters you'll change on time. If you cook on gas, fry often or already have a duct path, a ducted hood is the stronger choice.

For types, sizes and installs in one place, read the complete ductless range hood guide.

Frequently asked questions

Do ductless range hoods work as well as ducted ones?

Not on every job, since a ducted hood sends heat, steam and gases outside while a ductless hood returns filtered air to the room. For light everyday cooking a ductless hood can be enough, but gas cooking and heavy frying call for the stronger ducted setup.

How long does a ductless range hood charcoal filter last?

It depends on how often you cook, and SNDOAS suggests about every 3 months with 3 to 6 months for its CF-0475, while CIARRA says every 2 to 4 months for its CACF006. Follow your own manual, and change the filter sooner after heavy cooking.

Do ductless range hoods need a special filter?

Many do, because the charcoal filter does the odor work when the hood doesn't vent outside, and some makers sell it separately. Filters fit by model number, so check the number on your own hood and never assume one filter fits every hood.

Is a ductless range hood good over a gas stove?

A ducted hood that vents outside is the stronger choice over a gas range. A ductless hood can still catch grease and help with odors, but it does not move combustion gases out of the room, so read your range and hood manuals before you decide.