I'm a CID, not a CKD, but I do adhere to NKBA guidelines. I just double-checked and there isn't a specific requirement for hood width other than "a correctly sized, ducted ventilation system with a minimum 100 cfm". So that says to me that as long as the hood has enough horsepower to accommodate the cooking you're doing, the width doesn't really matter. Unless you've got a restaurant-style equipment set up that requires a huge hood, going with the same size as the range/cooktop shouldn't be a problem with today's hoods.

I've never in my life been in a kitchen (except mine) where the hood was wider than the cooktop. Alas, I do notice these things. I don't believe it was ever the norm.

If you wait long enough, I am sure you'll get a good reply from @kaseki explaining, why the overhang is important. The physics simply requires more than 100% overlap in order for the hood to work correctly. Cooking fumes raise up in an expanding cone shape.

Having said that, if there simply isn't enough space, then some people have resorted to making the hood the same size as the range. It won't work as well, but it's better than nothing. Similarly, I see a lot of hoods that don't cover the range front-to-back. This isn't great, but it frequently is done out of necessity, as the hood otherwise gets into the sightline.

Kitchen design is all about compromises. You know that what you are doing is always going to be a problem. But doing it "correctly", creates a new set of problems somewhere else.

That could be a rule for those who are designing fancier, or more "professionally"/intensively-used kitchens than say, 90-95% of residential kitchens where space (or price) is a premium so hoods and ranges generally matched widths (also for aesthetic symmetry).

The extra overlap/overhang is a good idea and, in a way, should be mandatory so that steam and other vapours from cooking vessels don't hit the bottom of adjacent cabinets.

You just made me go recheck my cook top: 3 Miele modular units (they were there and I am not in a hurry to spend to replace them) which are ~33" total in width, to which I will be mounting over a 36" VentaHood professional hood. Could have been larger but the distributor didn't have a 42" demo for sale and this hood is going to be hanging on a bare wall (nothing else except a window and magnetic knife racks) so no adjacent cabinets to worry about . VentaHood for one recommends the hood overhang being 3" on each side, or 6" wide than the cooktop.

I have a hood that matches my cooktop (not my design) and it drives me batty- thanks to this forum where I have learned the should and whys of kitchen design. Ignorance was bliss.

Sorry. It depends make up air, it depends type and venting, it depends what and how you cook, it depends how you use the near adjacent counter tops, and how much you'd like to hit your head on a sharp corner.. It depends GREATLY upon using the hood correctly, and turning it on well before actual range top cooking takes place. So.........it depends. It depends if you are able or willing to sacrifice an upper cabinet..... and other factors as well. The only "rule"? Not smaller than the width of the cook top.

Really, you "cringe"? Not everyone has a large enough kitchen to fit a hood 6" wider than the cooktop. Not everyone wants to forego the upper cabinet storage. Not everyone wants to pay additional for a wider hood. Chiflipper - reality check.

Anyway, if you have cabinets on either side of the hood, they will help to corral the effluent if you can't fit a hood 6" wider than the cooktop. You will get greater exhaust benefit if you go deeper front to back. Many hoods are only 18-20" deep, leaving the front burners uncovered. It's best to spend extra, if it can be afforded, to get a hood 24" deep. Some people get 27" deep hoods and love them, but those are usually quite expensive.

There are building Code rules about MUA, but they vary by locality, and are a complex topic.

The only other "rule", which is imposed by the hood manufacturers, is to make sure your exhaust duct diameter matches the diameter spec'd for that hood. So many people have ducts that are 6" diameter or smaller, buy a hood that needs 8" or 10" duct, and then complain online how noisy and ineffective their hood is, like it's the hood's fault.

There is only one reason and one reason only I have a 42" hood over my 36" all gas range. I did it to get around the proximity guidelines/rules/code of my lowered uppers to the range. By adding that additional 3" on each side I was able to hang the cabinets lower than standard 16-18 inches.

I cooked on my range for months without any hood since we had some problems with the order. Since I do not run a Chinese Kitchen nor a professional kitchen of any type we did just fine. the cabinets survived and so did the walls and ceiling. For years in the past, fans in kitchens were for basic ventilation. Grandma simply opened a window. Only with the onset of the open floor plan did they become a "thing". Of course the manufacturer's jumped on the chance to oversell the products. Like granite and stainless and all the other stuff everyone needs to have according to the industry and those connected with it. It's the $$$$$$

IMO the CFM of the hood needs to be good enough to capture the stuff from the stove I use a 36” hood over a 36” range but high CFM and it works perfectly.

Marry an engineer.

We've had a 54" hood over our 48" range top since 1995.

@watchmelol

Haha.

This excerpt from that link is so apropos to, well, as she suggest, any single topic on the internet:

• "Specifically, a particular element to the internet that pervades every single topic that people can possibly form an opinion about: the mindset that there is ONLY ONE GOOD ACCEPTABLE WAY to do something that has zero impact on anyone else’s life.

• The ONLY ONE GOOD ACCEPTABLE WAY people believe ONE THING, and then that is ALL THEY BELIEVE and they make it their life’s work to make sure anyone not doing THE WAY is immediately disqualified from life, clapped in irons, and dragged to the town square to be flogged for idiocy.

  Which, upon reflection, is the source of all human conflict through history: your own opinions are fine, but other people’s are moronic and intolerable and deserving of the flaming cannonballs with chains.

Unless they happen to agree with you, in which case they are well-informed"

Sorry I missed the start of this party.

A cooking plume rises from the hot pan base and contains cooking effluent -- moisture, grease, and odor. The cooking plume is supplemented when cooking with gas by the additional hot combustion products of the gas flame. This cooking plume rises at some velocity depending on how hot the surface is, and may reach 1.2 m/s cooking over a gas burner, and somewhat less cooking over an induction hob. [I don't have time right now to dig out the research report for the value.]

As the plume rises, it also expands. If all of the plume is to be captured by the hood one or both of two things has be be true: (a) the hood overlaps the plume, and (b) the air flowing into the hood entrains all of the plume that might escape.

Generally, (b) is very difficult to achieve at air flow rates not exceeding one's tolerance for noise and/or exceeding the cost-effective limit of the hood blower size. Some portion of (b) can be achieved by side curtains or skirts on the hood (usually done on commercial hoods) or by cabinets on the sides. This leaves us with (a), which leads to making the hood overlap the areas of likely pan bases by some amount. The amount is determined by the plume expansion angle, which is roughly 10-degrees from the vertical, making the plume behave as an inverted cone. From this one can determine the overlap needed as a function of the distance from burner to hood entrance aperture.

The rule of a three-inch overlap accounts for typical hood heights and the fact that the range or cooktop extends beyond the hot cooking surfaces. At 30 inches of gap with a tangent of 10 degrees of 0.18, the pan overlap should be 5.3 inches. A 3-inch range overlap will be in this ballpark if the pan base doesn't intrude into a 2.3 inch zone at the range edge.

Similar considerations should be made for the front-to-back hood aperture distance. If cooking on front burners is to be done producing undesirable effluent, then significant overlap in that direction is also desirable. Note, however, that with a wall mounted hood having side cabinets, the updraft of the hood air flow will likely bend the front burner plumes a bit and gain a couple of inches of effective aperture in that direction. Because a typical hood uses a portion of its front to back distance for lighting and controls, there will be a bit of a contest between the portion of the hood front to back depth not being part of the aperture and the air flow that will favor inward air flow at this surface.

kas

So Rai Kai

Should I dismiss make up air in my future BS rangetop? It's not required here by code? Does give me pause and wonder. Kaseki probably has a differnet opinion whose opinion I value much but reading http://victoriaelizabethbarnes.com/options-for-no-range-hood-over-stove/

I laughed and now wonder how important is all of this in the greater scheme ? Just musing.

Inga

Things will work much better if there is some way for air to enter the room. Older buildings frequently have a lot of leaks, and in temperate climates people often keep windows open year round. For low CFM that's likely good enough. For higher CFM or if the building is sealed well, that won't be true. And if backdraft is a possibility, then you really should plan on a MUA system.

But if none of that applies, you can always start without one, and then add it later, if you feel you made a mistake. A passive system is relatively easy to add

I guess the people who insist they don't need a range hood aren't grilling salmon or herring for their cat, or make Cajun blackened food.

Even with a good smoke hood, I find a film of grease in the upper reaches of the kitchen.

There is a very simple mess free system to grill indoors. It's called a broiler. Many ranges that have high output burners have very nice infrared broilers. Mine does. Someone who takes the time to understand the science of cooking can even use a standard broiler with excellent results with minor tweaks to the process.

On the subject of make-up air. [Repeat broadcast]

There is always make-up air; no air is exhausted through the hood system that didn't somehow get into the house. Without deliberate MUA, however, the flow rate of the hood will be reduced even below that determined by the blower's fan curve and the pressure losses of the hood filtering and duct path. If one wants the hood performance he has paid for, an MUA method with low pressure loss is needed.

Also, in many modern houses, MUA is needed for safety reasons, but I won't repeat them here.

I will look at a MUA inlet system once I install my new Ventahood. I know I had to crack a window open in my previous (old and leaky) house whenever I had the two fans running at full tilt.

Fortunately, I can use a soffit but do have to insulate well. There's an 8" fresh air intake (but a sprung damper on this) in the basement but that is a bit far away.

Far away can be good if the path is clear. Distance may reduce turbulence at the cooking area. Turbulence is the enemy of good capture by the hood entry aperture.

hood & cfm sizes are determined by the cooktop requirements

Wolf is recomending oversized on islands. Some ranges require 18" height clearance 6" to each side, which would accommodate wider hoods also if desired.

I've read the "no hood" article... its funny and near true. I don't believe there is a requirement for a hood all the time, but clearances are important.

I live in a cave, too. I have never had a hood. In fact I cannot think of anyone I know that has a hood. I have an OTR microwave ( shhhhhh) with a vent that I have NEVER used. I do not fry foods nor do I cook spicy foods. There is no grease on our cabinets, walls, etc. I mentioned this one time before and received a very snarky comment from a pro.

We are residential lot developers and have built spec homes. Not one time has any contractor, inspector, or code official ever mentioned a hood. I am not saying this for any reason other than to state facts.

"The responses varied… but there were an ALARMING number of respondents who were EXTREMELY BOTHERED by the fact that this woman was not gutting her kitchen to the studs and reconfiguring everything towards the goal of direct-venting the range hood… and she should probably just go out and rent a bulldozer THAT VERY NIGHT and knock it all down to the ground while flagellating herself for having considered any other option."

I'm dying.

YORO.

"Not one time has any contractor, inspector, or code official ever mentioned a hood"

Grapefruit1-ar - It's hard to know how to respond to your post. It's such a dated and old-fashioned view. Even if your experience has been that you don't need a hood, there is much greater emphasis today on indoor air quality. Especially in new builds, in which the current insulation and building materials make much tighter houses than in decades past. It's unfortunate that you are so stuck in your ways, up in arms, and closed-minded against hoods. It's not like they add some humongous cost to a new home build.

Why the outrage against something that only benefits a home and its homeowner? I find it hard to believe that you are building homes with no kitchen exhaust, and no one has said anything. What price point are these homes?

I find it hard to believe that you are building homes with no kitchen exhaust, and no one has said anything.

I am not really surprised. The inspector won't say anything. In fact, in many jurisdictions they are explicitly not allowed to say anything. They are supposed to comment on code violations. Anything else (shoddy workmanship, poor design choices, ...) they are expected to stay silent on.

And the contractor generally couldn't care less. They take the drawings that the architect provided and build exactly what it shows on there. Some of it might be obviously ill-advised, but they don't get paid to second-guess the architect.

The architect might say something. That depends on the scope of their work. If they were hired to design exactly as spec'd, they won't waste their time to research better solutions. If they were hired to advise on best practices, then they should speak up.

In the end, the only people saying something are going to be the buyers. And they will either decide that they can walk away from the house (so, you'll never know), that they can retrofit a hood for less than $1000 (in which case, they'll only mention things in passing if at all), or that they honestly don't care for a house in this market.

Since I have worked with a couple of people whose past kitchens caught on fire by grease fires, I find the question a good one.

I have seen several kitchens where the adajcent cabinets look either too low or too close to gas stoves. I find combustible material close to gas stoves quite concerning.

When in doubt, 3" wider at least on both adacent wall cabinets. Keep tall cabinets & any cabinets that "rest on countertop" at a safe distance.

The worst fire damaged kitchen I saw was when a grease fire flamed up a tall cabinet panel that was too close.

Always adhere to the appliances manual's specifications for installation guidlines.

As for the vent types & needed suction, I hire an expert HVAC Pro to consult & install.

Better safe than sorry.

Wow, Frieda, " outraged"? I said that I was stating facts. Some of us live in a cave. We have not caught up with the rest of the world. I have no idea why contractors, builders, inspectors, etc. have never mentioned hoods being necessary, but they have not. I do not have a hood.

Just for fun I went on realtor.com and looked at the first 10 houses that I came to that ranged from $600,000 to $ 1.6 million. 7 out of 10 had over the range microwaves. The $1.6 million had OTR micro. The 1.1 million had a hood. I was just curious to see what is happening in our area.

Sure, range hoods are a first-world "necessity"....but I tell ya, in our new build there are several things that I am just giddy about: an exhaust hood that exhausts to the outdoors (omg, what a concept!), a Hide-A-Hose, and the dog wash in the garage.

I'm not a fancy cook but for too, too many years I have lived with, yum, next-day-fried-chicken smell - can't wait to put a good exhaust hood through its paces.

And for those not in the 1st world, kitchens are outside (or the house is (very) "leaky"). I suspect most people who could have ventilation would choose it. I remember some people of my ethnicity smelling of cooking smells because they apparently didn't use the hoods (used to well-ventilated kitchens).

There was a time when people believed that there was no harm in smoking cigarettes. Or that asbestos caused no harm. Or that industrial chemicals could be safely dumped in to the ground or a stream.

As time moves on we learn a lot about what is and is not so good. The U.S. has the least healthy population and highest rates of preventable disease of all developed countries - because we mostly drive rather than walk or bicycle for our transportation (and eat McDonalds, Wendy's, Outback steaks, etc.). Millennials will likely live longer and have fewer diseases because they've learned this and are doing something about it.

Indoor Air Quality, IAQ, is something else we've learned about. Fortunately not as unhealthy as smoking or breathing asbestos (as far as we know anyway) but still a health problem in newer and more sealed houses. As well as an aesthetic problem for those that don't like waking up to the remaining odors from last nights pan fried salmon (or don't want guests turned off by the smells of kitchen effluent when they're trying to eat).

We didn't have a hood in the house I grew up in (and where I learned to cook) nor did my wife and I have a hood in our first house (1946 cape cod) that we lived in for the first 5 years of our marriage and where we did a lot of cooking. I'm very thankful for the hood we have now, as anemic as it is, and looking forward to a much better hood in our new house.

For More: https://www.gardenweb.com/discussions/5161173/hood-faq

To the original question... 6" overlap on all sides is good. 12" overlap to the front is better. A larger hood can actually use fewer CFM's than a smaller hood - and will do a better and quieter job). It all depends on each person's desires, what kinds of things you cook, how often you cook, how sealed your house is, and your tolerance for odors and other effluent. OTOH, if you're happy with your current hood that's the same width as your range then for you there may be little noticable benefit to larger.

We currently have a 42"x27" over our 36" range and will have a 60" x 34" over our new 48" range. Our new one will likely be much quieter and work better than our existing one.