If you duct it, you will vent 940 cfm. If you don't duct it, you vent 0 cfm. In my opinion, that is a lot of lost performance.

Without a duct, you might as well not have one at all. IMHO.

Weedmesiter--I could not agree more.

Lauren--not ducting a ducted hood is not an option. If you choose not to duct you need a ductless (aka recirculating) hood and, in my opinion, you may as well have no hood as recirculating hoods are pretty much useless. They vent back into the kitchen--they do have some baffles and filters but they do very little.

If you can duct it do it. It's well worth the money.

Lauren,

Are we understanding you correctly? Are you suggesting to have a hood that goes nowhere?

-Stooxie

What's your stove? That 940 cfm spec is normally figured on how much hot air you might need to pull *out* of the kitchen. Through a duct. And 940cfm is a lot.

Ductless hoods may remove some grease from the air before returning it to the kitchen, but that's about it. What kind of cooking will you do? If there's going to be much frying, braising, wok cooking -- you might look at hoods that are built more for effectiveness and less for looks.

I agree with meister !

You might as well just open a window in the kitchen instead.

Thanks for all the input!
Wow - I didn't know that ducting made such a HUGE difference in performance. The hood I like can be set up as either, but after reading all the unanimous feedback, I'm definitely getting it ducted out. Thanks!

We had a ductless before we redesigned the kitchen & installed a ducted unit. The ductless did absolutely nothing beside make noise. If you are going ductless then you might as well just put up a couple of lights, because that's all you are really going to get out of it.

I have decided to run a duct.
Thank you all so much!

(Ductless hoods--good ones--are still quite a bit better than nothing. They DO collect grease and they kinda remove odors if you keep the carbon filters fresh. Ducted works much better, but in spite of the hood vent passions on this forum, ductless are not useless.)

I beg to differ. We had a Zephyr, 600cfm ductless. Carbon filters, the works. Cleaned religiously. I could have done a better job with a Hoover & a ladder

NOt a good one, apparently.

fori - I've been doing this a long time and have done a kitchens with ductless hoods.

While you are technically correct that they are not useless - they do not perform anywhere near like you are intimating.

We do them when there is no other option like a high rise that doesn't allow wall/roof penetrations and the client simply wants the "look".

The carbon filters will eliminate some odors and the filters some grease - but on the whole they let about about as much pass through as capture. And I've seen em all - budget units from Asia to German and Italian units costing $3000.

How often do the carbon filters need to be changed to keep them "fresh"?

i have ductless and had ductless in my last house - if/when I remodel in this house, I'd put in duct work.

I agree ductless is useless -- so I never even turn it on!

I would also imagine it to perform louder because of the carbon filters adding resistance to the air being sucked in.

Laurenfounder,

Don't be seduced by the kind of sort-of's. If you read Fori's and Antss's posts carefully, you'll see that they actually pretty much agree that a really good ductless hood can be better than nothing at all, and that it will do something, but that doesn't make it a good alternative to a proper duct and blower system. Think of half the grease from frying potatoes or stir frying in a wok, where there's a lot of aerosolized grease, half the steam from a big pot of pasta, and half the smell from stinky fried fish or corned beef and cabbage. Even a good ducted hood likely won't get 100%, but it will get most of it. Mine probably gets about 98%. I don't have noticeable smells and residues--just assume that a little must escape. I don't want to live with the half that's left behind by some inferior contraption. Do you??

If you have the choice to run the duct do it. The lack of utter uselessness posited for the best of recirculating hoods doesn't approach the usefulness of properly ducted ones. While you're having the ductwork done, make sure to talk to your HVAC guy about make-up air too, so that while you're benefitting from all that pulling power, you don't suck all the air out of the house (bad for gas furnaces and other flames).

laurenfounder I think nobody in this forum knows specifically how often the carbon filters in a ductless need to be changed to keep them "fresh", and this may be a sign of several conclusions. One is that there is almost no-one in the world (although one might pop up now) who actually changes carbon filters. And that is (probably) because owners of carbonfilter ductless fans conclude that the whole contraption is almost ineffective even in the best circumstances, and so they simply never turn these fans on (so they have no idea if the carbon filter would be better off being replaced or not). I doubt anyone "knows" by smell or by usage when to replace a carbon filter.

Many people refrain from cooking certain kinds of meals. Restaurants often see customers ordering food of the kind that these customers cannot make at home.

Thank you for all the feedback from each and every one of you. You've all been very helpful.
I have worked out the numbers with my contractor and building a duct wouldn't cost me as much as I thought it would. So, for long-term it DOES make sense to have our hood ducted. In addition, I'll gladly miss out on the carbon filter "head-ache" too.

Smart move. I used my vent hood every day. Often run it when the oven is on as well.

Better price out a set of the charcoal filters and factor the replacement cost into your decision - they aren't cheap !