Ducted vs ductless range hood

[Zachary Hoyt]

I have never installed a range hood and I am hoping for some advice. We have gotten by without one for the last year plus, but it would be nice to have one when stir frying etc. At the farm where I lived for 21 years we didn't have one but the stove was in a 7,000 square foot converted barn, so there was lots of air for any smoke to dissipate into. Here we are a bit under 1,000 square feet, so it's more noticeable.

I didn't realize there were two kinds. We are in a pretty cold climate here so I am a bit reluctant to make another hole in the wall, but if that is the way to go that's fine too. I had not heard of ductless before, and have no idea how effective they may be. I'll be grateful for any advice about the whole question. We have a 30" electric stove in a corner, against the outside wall, so putting in a duct will be pretty easy. I haven't built a cabinet for the space above the stove yet, so I'll do that after I have the hood to make sure it fits. There is a currently unused circuit with a GFCI plug right above where the hood would be, so if they plug in that will be easy, or I can open the box and wire the hood directly if necessary.

[Bill Howatt]

Also in a cold climate and there is always some air leakage only noticeable in the cold winter days :). Mine was probably like your description - stove against an outside wall so only a short duct to outside. To help heat loss in winter, I made a metal plate with magnets that I could attach to the underside over the stove to better seal it. However, there are numerous physical layouts so it may not be possible on some.
IMO, ducted is more efficient and preferred albeit with some heat loss and you don't have to keep buying filters and some activated charcoal filters for some models are expensive. Filter expense may be worse than extra heating expense. Some outside flappers are better than others for sealing when the unit isn't running. Also remember, that you are blowing conditioned (heated or cooled) air out when venting.
Right now we have a ductless and just run the fan without filters and this really doesn't do much but we mostly just don't bother running it; but that isn't an answer to your question.
Some models are convertible - they come with the hardware to make it either a ducted or ductless so you could try ductless and convert later - or vice-versa, although you would have a hole to cover if you went ductless.

[roger wiegand]

If you can get a duct pipe to the outdoors, by all means do it. The filters only catch large particles, odors and the more dangerous small particles are getting blown back into your living space. You'll be much happier with that stuff outside, and you won't have a film of congealing grease on every surface in your kitchen. Modern units of better quality have flaps that seal much better than in the past.

[Jim Becker]

The only good range hood is one that puts the grease that doesn't get caught on the filters, fumes and steam outside. Any range hood that vents back into the room is just putting the fine particulate grease, steam and fumes back in the air you breath. Even the better over range microwaves that include the hood function can vent outside. Personally, I hate the microwave in that position cause it gets in the way of my head when cooking, so I went with a Hauslane hood and ducted to the outside here at this house we bought two and a half years ago. There is an open soffit behind the wall with direct pathway to the outside of the house, but the builder never installed an actual vented hood in the kitchen. I fixed that at the same time I was installing my induction range.

Yes, using a real vent will move some air, but by using it only while it's needed it's not a problem unless you have a "super sealed" structure with no formal way to provide makeup air. I kinda think that's not the case in the house you're renovating up there where you are.

[Zachary Hoyt]

Thank you all for your advice. I'll go with a ducted model for sure.

The house is fairly well sealed as it is entirely insulated with spray foam, and I don't have a formal way to provide makeup air. The foam installer said that I should get an air exchanger thing (I can't remember the proper name) with a heat exchanger so the air would be changed without losing heat, but so far we have not died of suffocation or otherwise had a problem so I haven't put one in. We have a wood stove and bathroom vent fans, so I don't imagine adding a range hood should cause a problem in that way, as we wouldn't likely be running everything at once. I also haven't installed the outside air kit that I bought for the wood stove, as it has not seemed to be needed and it would be in the way since the stove is in the middle of the house rather than by the wall. The windows are all new modern ones, but they are not totally air tight where the sashes meet the frame, and there are probably other leaks. I don't think we'd be running the fan for more than 10 or 15 minutes at a time, and not that often.

The wall is only 4" thick so it is not hard to make a hole, it's just a matter of putting it in the right place and not hitting any wires or studs. I'll have to look back at the pictures I have from when I was working on the house before the foam was sprayed. Now that I know what to look for I will try to get the hood put in before winter.

[Paul F Franklin]

Absolutely ducted if you have a choice. I've had both and there is no comparison. Yes there is some loss of conditioned air, but that's the price you pay for getting rid of the indoor pollutants and grease generated by cooking. Most folks can get by with a unit that exhausts 300-600 CFM on high If you have a commercial type range with high output burners or an island where the hood is higher up, you might need a lot more.

Most houses that weren't built to be really tight will have more than enough air leaks to provide the makeup air for the 300-600 CFM range, but if you have a really tight house or a bigger hood you may have to add a makeup air duct. The air you are blowing outside has to come from somewhere. Recent building codes require makeup air unless testing proves the hood doesn't depressurize the house. This is especially important if you have a older gas burning furnace or water heater that is not power vented or draws intake air from outside. Makeup air kits include a powered damper so they only open when the exhaust blower is running.

It's worth paying more for a hood that is relatively quiet because a hood that sounds like a jet engine just won't get used. Even the best are noisy on high, but the cheapies are especially loud, even on the lower speeds. Hoods almost always have a damper as part of the hood, and then there is usually a second damper in the wall cap, so air leakage when the hood is off is minimal. Most better hoods will need at least a 6" vent; higher CFM units need bigger vents.

[Kevin Jenness]

Thank you all for your advice. I'll go with a ducted model for sure.

The house is fairly well sealed as it is entirely insulated with spray foam, and I don't have a formal way to provide makeup air. The foam installer said that I should get an air exchanger thing (I can't remember the proper name) with a heat exchanger so the air would be changed without losing heat, but so far we have not died of suffocation or otherwise had a problem so I haven't put one in. We have a wood stove and bathroom vent fans, so I don't imagine adding a range hood should cause a problem in that way, as we wouldn't likely be running everything at once. I also haven't installed the outside air kit that I bought for the wood stove, as it has not seemed to be needed and it would be in the way since the stove is in the middle of the house rather than by the wall. The windows are all new modern ones, but they are not totally air tight where the sashes meet the frame, and there are probably other leaks. I don't think we'd be running the fan for more than 10 or 15 minutes at a time, and not that often.

The wall is only 4" thick so it is not hard to make a hole, it's just a matter of putting it in the right place and not hitting any wires or studs. I'll have to look back at the pictures I have from when I was working on the house before the foam was sprayed. Now that I know what to look for I will try to get the hood put in before winter.

Late fall and winter will be a test of air quality and adding a ducted range hood will up the ante. You may well need makeup air for the hood, and you may also need it for air quality. When I built my house it was fairly tight with no defined air exchange except what the wood stove and bathroom fan pulled in through the cracks. Result, high humidity, lots of condensation on the windows, and I usually had some kind of lung mung every winter. I wound up installing passive wall vents in the bedrooms and running the bathroom fan on a timer about half the time. That improved things considerably, but even now the range hood can backdraft the woodstove if it is not burning hot enough and often will open a window while running the fan on high. That said, a ductless hood is hardly worth having in my opinion.

The next few months will give you an idea of how the new place works but don't be surprised if you need to compensate for the relative airtightness after living in a barn. Also, watch out for moisture problems in the walls and attic, foam insulation can concentrate rot pockets at areas of air leakage. Air to air heat exchangers are used in most new houses in this region for good reason.

[Zachary Hoyt]

Thanks for all the advice.

We just have a regular 4 burner electric stove, so it's not a huge load. I am thinking a fairly low-powered fan should be enough, given what we need it to do. The noise factor is something to think about, but after the old restaurant fridge we used to have at the farm that you could hear all over the building we're probably a bit desensitized to that kind of thing.

We've been through one winter already, so I imagine things should work okay. Last winter I had a pot of water on the stove all winter trying to keep the humidity up to around 40%, but sometimes it would still get down to 30% or so. Aside from the wood stove the house is all electric, so no gas related issues. We had a huge gas stove with 6 burners, two ovens and a grill/broiler at the farm, but after reading about indoor air quality concerns from combustion byproducts and having met some people who had been badly injured in a propane tank explosion I didn't want to have any gas stuff in the house since I was setting it all up new. I still use a propane and a MAP torch in the shop sometimes.

[Bill Dufour]

Big commercial range hoods have makeup vents connected to the outside that create an air curtain in front. This means the makeup air drops from the front of the hood down to the stove then up the back of the stove and out. In theory very little air is drawn from inside the room. I grew up with a gas stove that had a chimney vent for the oven. people here said they never heard or saw such a thing.
Bill D.

[Lee Schierer]

I would go with a ducted range hood. They do a much better job. Be sure to get an outside vent with a self closing door. The self closing vent will significantly reduce the air infiltration due to the wind. Most houses have enough air leaks for make up air, but an air to air heat exchanger might be needed if your house is really tight and/or if you have a gas water heater or furnace. The newer water heaters and furnaces with pvc exhausts aren't a problem unless the installer failed to install the air inlet piping for them.

[Alan Rutherford]

One more vote for ducted - and I have not always lived in Florida. Haven't done it yet, but I've considered adding makeup air with the source low and behind the stove.

[Steve Demuth]

Thank you all for your advice. I'll go with a ducted model for sure.

The house is fairly well sealed as it is entirely insulated with spray foam, and I don't have a formal way to provide makeup air. The foam installer said that I should get an air exchanger thing (I can't remember the proper name) with a heat exchanger so the air would be changed without losing heat, but so far we have not died of suffocation or otherwise had a problem so I haven't put one in. We have a wood stove and bathroom vent fans, so I don't imagine adding a range hood should cause a problem in that way, as we wouldn't likely be running everything at once. I also haven't installed the outside air kit that I bought for the wood stove, as it has not seemed to be needed and it would be in the way since the stove is in the middle of the house rather than by the wall. The windows are all new modern ones, but they are not totally air tight where the sashes meet the frame, and there are probably other leaks. I don't think we'd be running the fan for more than 10 or 15 minutes at a time, and not that often.

The wall is only 4" thick so it is not hard to make a hole, it's just a matter of putting it in the right place and not hitting any wires or studs. I'll have to look back at the pictures I have from when I was working on the house before the foam was sprayed. Now that I know what to look for I will try to get the hood put in before winter.

If your wood stove draws well and doesn't smoke, assuming it doesn't have its own provision for makeup air, then your house isn't as super tightly sealed as you imagine. An airtight woodstove will typically draw up to 50cfm, and it's noticeable in your ability to get a fire to draw when the house can't provide that. But a range hood is going to typically be 10X that in draw. You'll know if your house is really tight, if the wood stove starts to smoke or the fire flag, when you turn on the range hood.

[Jim Becker]

Zachary, you mentioned you have a wood stove...given the spray foam sealing, the insulation installers advice to have an air exchanger is even more potent, unless your stove has a direct draw of fresh air from the outside.

[Zachary Hoyt]

I don't think the house is all that sealed in reality, but I am usually skeptical. When my parents had a house built in 1984 the contractor told them "it's going to be so tight you'll need an air exchanger" and put one in, but the only use it had when I was growing up was to leak sometimes in a heavy rain and make a puddle behind the couch. So when the foam guy said we'd need one I took a wait and see approach, figuring I could put one in later if necessary. Our stove is quite small, and has good draft without installing the outside air kit I ordered, even when the bathroom fan is running. I imagine the range hood will move more air, probably, so it'll be interesting to see what happens.

[Tom M King]

I like to use the exterior mount fan, and run a duct that's big enough to clean the inside of. You can then make the "range hood" however you want and line it with sheet metal.

edited to add: If you end up building the whole system like I do, buy the filter you want to use to start with so there is a good mounting place for it inside that's easy to access and operate.

[Steve Demuth]

In reality, very few are that tight. The standard energy audit test is to pull a .2 inch of water "vacuum" inside the house and measure the amount of makeup air required to maintain that pressure. On our house, that gives a result on the order of 4 full air exchanges per hour. 3 is considered an "air tight" new build. But that's with significant negative pressure in the house. The natural infiltration rate is somewhere closer to 5% of that, or 5 hours per air exchange for us, which for our house comes out to almost exactly 50 CFM natural infiltration. In reality I think 5% is optimistic, and our natural infiltration rate is quite a bit higher that that, but I have no way of proving it, other than to note that our woodstove works just fine.

[Rob Luter]

Ducted for sure. My last house had a 600 CFM ducted hood and it was a super tight house. There was a make-up air duct routed from the exterior of the home to the cold air return of my HVAC unit. When the hood turned on it pulled air in and prevented the water heater from backdrafting. The long duct run heated the air up enough in winter you never noticed it. Simple but very effective

[Roger Feeley]

When we built our house, we opted for basically no hood and I regret it but not much. The duct would have been really long and would have needed special framing and would have gone through some cabinets. If I had it to do over, I would try a bit harder. It’s not too big of a deal since we don’t fry much. But I’m a +1 on ducted.

[Patty Hann]

Ducted.... but my house isn't super tight and I always have a a couple of windows cracked open, anyway.
Hood is a Kenmore from 1990 ($120) that Consumer Reports rated better than even the Jenn Aire and Viking models (moved air just as efficiently, was quieter** and 1/4 the price).
Has 2 lights, one on either side rather than just one in the middle, which is nice because a light actually shines down on two burners. ( I have a 4 burner electric)

** Quiet/ pretty quiet or unobtrusive at the lower 2 settings....highest setting sounds like a 747 taking off :D.
But I don't recall ever having to use the High setting.

[Brian Elfert]

I would always recommend ducted for a kitchen hood. An non-ducted hood can't remove smoke or odors. A little bit is caught by the filter, but the rest is recirculated back into the house. I have a ducted hood. The HVAC company that installed the ductwork for the hood ran it above the cabinets and out the sidewall of the house. They said that is better than going through the roof, and I agree. I installed a wood panel over the duct work that matches the cabinets so you don't see the duct work.

[Patty Hann]

... The HVAC company that installed the ductwork for the hood ran it above the cabinets and out the sidewall of the house. They said that is better than going through the roof, and I agree. ....
Why is it better to go through the wall? (Unless maybe it's that you don't have to poke a hole in the roof which can potentially lead to a leak)

[Pat Germain]

I had a new range hood installed just a few weeks ago. We moved into our current house just over a year ago and, although the house is only three years old, it didn't have an actual range hood. It had the proverbial microwave over the range. The microwave had some puny blower motor inside which simply made noise and pushed some air directly onto the cabinet above. Yeah, completely useless. (In my opinion, this should not meet code.)

I bought a Hauslane range hood; just like Jim. :-) It seemed to be a good quality range hood with dual fans and LOT of CFM. Also like Jim, I hate the microwave over the stove thing and happily ripped that out. I installed the new range hood and hired a local HVAC company to vent it to the outside.

In fact, I called the HVAC company before I bought a range hood. I wanted to make sure I COULD vent it to the outside. The owner of the HVAC company showed up. Really cool and knowledgeable guy. Since my house is a ranch, he said he could easily run ventilation up through the cabinet, through the ceiling and then out the roof. He also complemented me on calling before I bought the range hood. Apparently, most people buy the hood then call. And, apparently, a lot of those range hoods won't work. So yeah, definitely call an HVAC company before you buy the range hood.

If you're wanting to install everything yourself, be aware there are MANY codes which apply. In fact, when I was watching YouTube videos about range hoods, I saw multiple guys installing range hoods with multiple code violations. They used flex tubing which is not allowed. They used an exit right next to a window which is not allowed. They also had many sharp turns which is a BIG killer of CFM.

Anyway, the HVAC guy showed up and had my new range hood vented to the outside in a couple of hours. It wasn't cheap; around $800. But for me it was worth it to be code-compliant, functional and, most of all, safe. Now when I'm cooking I can fire up that Hauslane without filling the house with smoke and smells. Turn it on high and it will make your ears pop!

Good luck.

[Carl Beckett]

Just to pile on - if you have a particle size meter test the kitchen.

All the concern about the shop air quality - and the highest reading I get on my particle meter is when frying bacon inside on the stovetop.

I have a filter type in the microwave over the stovetop. Useless.

Have contemplated venting to the outside (the microwave can configure for it), but my town has plenty of codes to follow and I havent done enough research yet.

[Zachary Hoyt]

I'm planning to vent the one I get through the wall. I don't know if it's better to just put an elbow on and go outside immediately through the back of the cabinet or if it's better to go up higher to just below the roof overhang to get better protection from water. I don't want to go through the roof since it's only about 2.5/12 pitch and would seem to me like a probable source of leaks, besides getting covered up by snow in the winter.

[Jim Becker]

Why is it better to go through the wall? (Unless maybe it's that you don't have to poke a hole in the roof which can potentially lead to a leak)

Typically longer ductwork run which is less efficient, harder to clean in the future and yes...a roof penetration.


I'm planning to vent the one I get through the wall. I don't know if it's better to just put an elbow on and go outside immediately through the back of the cabinet or if it's better to go up higher to just below the roof overhang to get better protection from water. I don't want to go through the roof since it's only about 2.5/12 pitch and would seem to me like a probable source of leaks, besides getting covered up by snow in the winter.

Just like with dust collection, the shorter the duct run, the more efficient it will be, especially with the lower CFM that's typically with many small, 30" range hoods. Balancing that, is appearance and interference with other things. You should do what's best for your particular situation for the location of the exhaust on the outside of the home. I was able to go direct to the outside from the hood with one 90º lateral bend and about 5' of straight duct because the range is on an inside wall, but with a soffit above. My hood uses 6" duct. The actual vent on the exterior is up high, in a sense, because it's above the house side of a patio and the ground level is about three feet lower than the first floor of the house.

[Brian Elfert]

Why is it better to go through the wall? (Unless maybe it's that you don't have to poke a hole in the roof which can potentially lead to a leak)

No potential of a roof leak.

[Brian Elfert]

Like Jim, my duct run has a single 90 and is about five feet long. It is at least 6". The HVAC company also insulated the ductwork. I only have an over the range microwave so the blower is noisy. It does work as I can see steam pulled towards it. I plan to put in a better range hood if/when the microwave dies. My biggest issue will be finding a place for the microwave as my kitchen is tiny and counter space is quite limited. I can't really change much about the kitchen without gutting most of the house and probably losing one of the bedrooms. The living room is tiny too and I can't afford to take any space from it.

[Zachary Hoyt]

Thanks, that makes sense. I will have the option to have a duct run with a 90 and maybe a foot or less of duct. I'll need to figure out where I can get the duct and the outside cover and such. The wall with the stove faces away from the road and looks right at the woodshed 8 feet away, so it's not a place where appearance is going to be critical. If I can keep the duct inside the cabinet that will look better on the inside, because the cabinet will not go all the way to the ceiling, which is close 10' in that area.

[Jim Becker]

Zachary, you can use normal 6" HVAC duct components from the 'borg or a mechanical supply. Just tape it well and be sure that any crimps are facing toward the outside so grease cannot get caught by them, just like you have to pay attention to crimp direction with dust collection. A slight downward slope toward the outside is a good idea. Use a good amount of foil tape to seal things up, too.

Brian, in this new to use smaller house, I opted for a much smaller microwave appliance. It's currently on buffet that's temporarily in the eating area, but I plan on a formal built-in "over there" so I can move my espresso machine to the new area and put the small microwave where the espresso machine is now. I have wonky circuits in this kitchen so I can't have the microwave on the same circuit as my countertop "many function" Ninja Foodie oven. The point here is that it's not just space...power also comes into play when finding a spot for these thangs! (I only use the microwave for occasional convenience...it's rarely used to actually cook things for meals)

[Jim McCue]

A bit late if you've already made your decision but I remember reading an article long time ago and it stuck with me: Recirculating Range Hoods Make As Much Sense as Recirculating Toilets

https://www.energyvanguard.com/blog/recirculating-range-hoods-as-effective-as-recirculating-toilets/

Unless your home was built really recently by conscientious builders focused on air sealing, I wouldn't worry about makeup air. I wouldn't worry about the ductwork elbows or route if it's only a few feet, that's the kind of thing that makes a difference when you're venting your dryer 30+ feet.

I've gotten higher quality parts like fan, insert, damper and wall caps from hvacquick and then the ductwork and fasteners from big box store. Hvacquick emphasizes minimizing noise, but aside from getting a higher quality fan in the first place you don't have room for a lot of silencing in a small space.

https://www.hvacquick.com/products/residential/Kitchen-Exhaust

[Tom M King]

When I was building new houses, I used the fans mounted on the outside wall. Duct ran straight from the custom made hood to the motor outside the wall. Inside the cabinets the duct ran through, the duct was boxed in against the back of the cabinet and finished like the rest of the cabinet interior. No buyer ever said anything about it one way or the other.

The ducts are really easy to clean out. You take the filter out of the hood, and you can see right to the fan. I had a local sheet metal guy that I went to High School with make the liner for the hoods for me to my measurements.

I was building everything about the houses, including the cabinets, so there was really no problem at all for me.

I can't find the exact fan I used, bought from a local supplier, but they were something like this, although backdraft damper was built into the fan unit. Variable speed, and they looked a little better than this one.

https://www.supplyhouse.com/Fantech-REC54-Wall-or-Roof-Mount-Curb-4-or-5-Centrifugal-Duct-Fan-116-CFM

[Alan Rutherford]

So much good information here. I installed a fan several years ago that was ducted but the intake was in the countertop behind the range. The range was in an island and we did it that way rather than install a hood. The intake would rise up several inches when you turned it on. The fan itself was outside the house and IIRC it was 1000 CFM or more. Generous ductwork, smooth curves, total length maybe 20 feet.

Didn't work worth a darn. The first problem was those times when I suddenly realized I needed the fan because grease was smoking on a burner or something else had gone wrong, it took too long for the intake to rise up and the fan to come on. For more general use, being behind the range even that big fan wasn't enough to make fumes or smoke move horizontally to the intake unless pan and lid were strategically positioned in the right place.

Should have installed a hood and of course it would have been ducted.

[Terry Wawro]

I've gotten higher quality parts like fan, insert, damper and wall caps from hvacquick and then the ductwork and fasteners from big box store. Hvacquick emphasizes minimizing noise, but aside from getting a higher quality fan in the first place you don't have room for a lot of silencing in a small space.

https://www.hvacquick.com/products/residential/Kitchen-Exhaust

Jim, Thank you very much for this website. I replace our old crappy range hood with a newer more powerful one a couple of months ago. It works great but it is very LOUD.
I being thinking about moving the fan into the attic above to cut down on the noise and could not find a solution on the web. This looks like the answer.