The user manual for the Culinarian is not online but the Precision is (see below) and the Cuinarian is basically a Precision with open burners. It recommends 1200 CFM. MUA may be a local/state building code issue (you should be able to call your local building inspector or a competent contractor). Otherwise there are a lot of considerations like the tightness of your house, your HVAC system and if you don't mind opening a window every time you use the hood.

We are getting a 48" with a 1200 CFM hood (Probably Modern Aire). I don't think we have any building codes related to MUA and my house is 90 years old, leaky with a hot water heating system. I'm going to gamble and take the "open a window" route to MUA.

Here is a link that might be useful: Precision Ranges Use/Care Guide

donfromma-
Thanks for the information. I'm going to have to check into our local code.

If anyone else has any feedback, it would be greatly appreciated!

rexroat

Hello,
I have done extensive research on the this subject as I am also planning on a 36" culinarian. Here is what I have found
1. It depends on if you plan to get the charbroiler. Charbroiler will produce more smoke than anything else you do. Personally, I am going with a 6 burner and no charbroiler. I will do my grilling outside even in winter.
2. I looked up recommendations for commercial equipment. Most recommendations suggest 200cfm per lineal foot. Recommendations for charbroilers is 300cfm per lineal foot. With this in mind, I am planning on a 600 cfm hood.
3. It is important to design the hood to naturally capture as much effluent as possible. In this case I suggest a 42"x27" hood. Also consider the volume of the sump. The larger the sump volume the better. The better the capture and containment, the less cfm's you need to remove the smoke.
In my opinion, you only really need high cfm's in a situation where you are trying to change the direction of the effluent like an undersized capture area, small sump, or a downdraft situation. Design the hood to naturally exhaust the smoke and you can get away with much less cfm.

I don't want anything to do with makeup air. It costs about $7,000 to do it right and you have to run a 15,000 watt heating element everytime you turn on your hood. This could cost $10 a day just to cook.

It seems that Trevor is planning to do some hood testing shortly. One test that I would like to see is which hood design will evacuate the most effluent with the least cfm. This hood will be the winner in my mind as lower cfm is less likely to depressurize your house and will be quieter. I personally believe 1200cfm is overkill in most situations, or people are going with high cfm because the don't like the look of oversized hoods and need to change the direction of the effluent.
Thanks

The manual that came with my 30" Culinarian specifies a 1,200 CFM hood for the 36" range.

We went with 600 CFMs for our 30" range (also the recommended size per Capital) and its plenty.

It seems like a pretty big jump from 600 CFMs for a 30" to 1,200 CFMs for a 36". Perhaps they are sizing it for a grill option. If you are going with an all burner range, I can't see where you would need greater than 900 CFMs and you could possibly get away with 600.

I agree with ribs1 that hood volume is at least as important as the fan rating.

Sorry,
I missed you op that said you are going 6 burner.
I think 600cfm is more than enough and with a properly designed capture and containment hood you could even get away with 300cfm

But if you get higher CFM you can run the hood at a lower setting, which might be quieter. The reserve power is there if and when you need it.

Yes Sayde,
But higher CFM could require make up air by code. Like I said before, a make up air system costs around 7,000 and requires running a 15k watt electric heater every time you turn it on. Thats like turning on 150 light bulbs everytime you cook.

In my city, make up air is required for any hood greater than 600cfm and the inspectors are serious about it.

sayde said: "But if you get higher CFM you can run the hood at a lower setting, which might be quieter. The reserve power is there if and when you need it."

Precisely. We're planning around a 36 inch six burner Culinarian, too, and the Modern-Aire PSL-040 insert that will go into my range hood area (cabinet maker is going to basically bridge over the range between cabinets, leaving a 42 x 27 rectangle into which the insert will go) comes with an infintely variable switch.

So the choice isn't binary - it's not zero cfm or 1200cfm - you just dial in what you need.

It DOES call for ten inch duct, and to many county/city inspectors that may raise flags about code compliance and make-up air. But the house we're building is extremely tightly sealed (ICF block construction, icynene foam under the roof) so we're probably going to incorporate a whole house ventilating dehumidifier into our HVAC system. We'd be doing that anyway to insure a good supply of fresh, clean air and a lower level of relative humidity (no small thing in Florida).

Apart from whether the MUA is a potential problem where you live, I think range exhaust capability is a lot like horsepower: there's no such thing as too much, and nothing says you have to use it all, all the time. :-)

"I don't want anything to do with makeup air. It costs about $7,000 to do it right and you have to run a 15,000 watt heating element everytime you turn on your hood. This could cost $10 a day just to cook."

We have designed a very simple, and inexpensive, makeup air system for our new house that passed inspection with our city's strict (California) MUA rules.

We are using an island hood (500cfm) that is electrically connected to a damped passive intake vent that puts MUA air into the house whenever the hood is on. The intake vent inlet is positioned behind the refrigerator to temper the air and cool the back of fridge when cold air comes into the house - the warm air at the back of the fridge is a perfect location to bring in unheated air.

We are in a pretty mild temperate zone (03) so we don't have many times of they year that frigid air will ever come into the home. In a colder climate we would have specified an HRV for the entire house anyway, but we were able to get away with a ventilation only solution to meet the new building code with simple damped passive MUA inlets.

another vote for 600cfm. I will be installing a 600cfm liner but increasing a capture area by using a 42" wide hood and setting a canopy to be larger than 22" between 25-27".

I will have a 36" range hood with grill.

I'm planning on a Capital Precision 36" range, no grill, and my contractor has not mentioned the CFMs of the hood, but has roughed in an 8" vent. I'm sure from the posts here that I would like to avoid the cost of having to deal with make up air! Can someone please give me a guess as to what the code is for northern california re. make up air? Is 600 CFM's the magic number? TIA.

juniork,
My guess is that in Northern California you probably don't need tempered make up air which is what can get expensive. In other words, you probably don't need to heat the make up air. If make up air is required, you probably only need a passive vent.
600cfm seems to be the magic number most places but it is lower in some areas.

Rexroat - I have a 36" 6 burner CC with a 42" 1100 CFM hood vented straight up. 90% of the time I run it on low setting and it is sufficient and quiet. Having said that,
a lot has to do with how far you have to vent, how many turns you have to make and how wide your capture area is.

Robj - you got a manual with your CC?

Sure did, homechef.

I could scan it into a pdf and email it to you, if you'd like.

Thanks for all the responses!

What we are looking at...
42" Viking insert (I would like heat lamps, Viking seems like one of the few offering them in 42")
http://www.vikingrange.com/consumer/products/product.jsp?id=prod180258#product-overview

We were told exterior ventilator would be quieter than the interior ventilator. The lowest CFM for the exterior is 900 CFM. I would prefer to go with 600 CFM with the interior model but am concerned about the noise level.

The range will be on an exterior wall. We're doing a complete renovation and the venting setup will be totally new. But I need to find out specifics of the ductwork set-up from our contractor.

Again, thanks for all the information! rexroat

Here is a link that might be useful: 42

I'm in nocal and just got done with a kitchen reno where we installed a 1600cfm hood. No MUA required and we had the inspector from hell. That said, MUA units not only help prevent backdraft situations but also help the efficiency of the hood by preventing back pressure. An open window usually suffices in temperate climates so that's why MUA is not a big issue in CA in general.

"We were told exterior ventilator would be quieter than the interior ventilator. The lowest CFM for the exterior is 900 CFM. I would prefer to go with 600 CFM with the interior model but am concerned about the noise level."

Have you played with some of these? (That actually are hooked up?) I think you're right that you can lower the noise a bit by moving the blower, and isolating it, but often, a fair bit of the system noise seems to come from the movement of air through the system -- starting with the baffles. The blower itself might well be a bit noisier on the 600 cfm internal setup, and certainly more perceptibly loud if you're standing by it, but given the same hood, same installation, same ductwork, etc., the total system noise in the kitchen might not be that different. I don't have any particular comparison to offer in your own case, and I'm not pushing one choice or the other, I'm just suggesting that it's worth considering actual operating noise to the extent you can.

"Have you played with some of these? (That actually are hooked up?)"

No, I haven't been able to play with them hooked up. I've had a hard enough time just seeing the hood insert in person, never the less hooked up.
We have a dedicated Viking store nearby but they don't feature their products for sale per se, it's more of a cooking school. So then I went to Abt next door and they have the hood insert on display but it's not hooked up.

"An open window usually suffices in temperate climate"

We are in Chicago (pretty much never temperate here), so the idea of opening the window in winter is a little chilly. I wish we were lucky enough to do so, we often ask ourselves why we don't move to a more temperate climate!

Thanks again for the responses!
The more information the better.

I have a 36" CC (6-burner), but it hasn't been installed yet. I believe the exhaust duct is 8". The contractor has spec'd 42" insert, and 600 CFM worth of VAH blowers. Any bigger and I think we trigger a requirement for conditioned make-up air ($$). The CC is sitting in my garage, so it'll be several more weeks before the project is done and I can tell you how this vent set up performs/sounds.

But I have a (dumb) question about the whole analysis: what is the primary purpose of the hood? I assumed it was to suck up the grease and smoke, at least enough of it so that it doesn't settle on your walls or set off the smoke detector. As long as it does that, I'm happy. I've also heard about it needing to suck up "cooking odors" so they don't permeate the house at mealtime. I don't care so much about that. But then it occured to me that with gas burners, maybe the hood is requried to evacuate noxious gasses that are emitted by the natural gas combustion? Does anyone know if that's the case? If so, does that part of the vent's job require more or less than other tasks. As in, 300 CFM will get enough of the combustion gasses out, but won't be adequate to preven smoke and grease from filling up your kitchen from time to time. 600 cfm is good enough for those two tasks, but you still might smell fish fying in the livingroom etc.

The combustion by-products of burning natural gas are CO2 and water, neither of which are particularly noxious, although you don't really want too much of either to collect within your home. The amount of these produced is usually minor compared to other cooking effluents like grease/steam/smoke, so gas ranges don't really need more powerful vents than any other fuel. If your burners burn red/orange/yellow instead of blue, you are experiencing incomplete combustion which produces CO as well as the above, which is a problem. If you are consistently burning yellow-red, get your range serviced.

Thanks cooksnews! That's what I was hoping to hear!

Wow, never heard of MUA but good thing it is not a requirement in Norcal as AMCOOK mentioned. Because I decided to get a rangetop with grill for an island, I severely limited my choices because I figured I needed more than 900 CFM. That meant external blower and our options came down to Viking and Wolf. The 10" duct is a little oval between the 2x10 joists and we had to bend the ducting so the blower would be above the sightline outside the kitchen window. So that means part of the ducting goes thru the master bedroom. That's the price to pay for the grill. I can grill outside year round but it is a hassle trying to manage a whole meal going in and out.

For those of you in Northern California who are saying that MUA is not a requirement in your area or that tempered MUA is not a requirement in your area, what cities are you in (if you don't mind my asking - I understand if you'd rather not say), and when did your plans pass permit review?

Montel, I am particularly interested to know when your untempered MUA plan went through...? It certainly does seem like the system you describe would be hugely less expensive than a tempered air system... but it doesn't seem like it meets the current codes, unless your city has not adopted the 2010 CA code in its entirety...?

The reason I'm asking is that I am also in Northern California and in the planning stages of a kitchen remodel, and struggling with the MUA issue. Reading my city's online building permit info, it seems that in December 2010, they adopted the 2010 California building code, which incorporates by reference the 2009 IRC, which calls for tempered (at least heated as required) MUA for any hood above 400 cfm. Because this new code adoption only happened in December (about 4 months ago), I was wondering if other NorCal cities might also be on the cusp (either before or after) of updating to the new 2010 CA building code... so if you got your plans permitted before the new code was adopted, your experience might be different from those of us who have not yet submitted plans for approval. Or maybe the timeline for various cities to adopt new California codes varies widely... I really don't know?

In any case, for those of you NorCal folks out there like me who are still in the planning stages, it would be wise to check with your local permitting department rather than assume that all of Northern California is subject to the same codes.

Best regards,
r.a.

Hi all,
I'm really sorry - upon doing additional research, it seems I was incorrect in my post above when I said that according to the 2010 CA building code and the 2009 IRC, make-up air needs to be tempered (or at least heated as required). As I now understand it, the tempering requirement seems to be the case only in certain areas of the country, and is not part of the 2010 CA code and 2009 IRC per se.

I do believe I was correct that the 2010 CA code and 2009 IRC require MUA for any kitchen hood rated over 400 cfm, however - I have now read that in a large number of online references. So it is still a good idea to check with your local permitting department if you haven't already address the MUA issue.

I apologize for any confusion or alarm that I caused with my earlier incorrect post.

Best regards,
r.a.

reluctantartist - can you please cite what code section(s) you are looking at regarding this requirement? I am *not* arguing with you, but trying to understand. I can't find anywhere where California has adopted the relevant section of the IRC.

The purposes of the hood and exhaust system are collection of combustion effluent (including trace or worse carbon monoxide), grease, and cooking odors. Correct grease capture can reduce risk of fire in the kitchen.

The primary function of the hood is capture of the uprising and expanding cooking effluent. This requires sufficient aperture area to overlap of the rising effluent cones. Capture is aided by the fan.

The primary function of the fan is containment and removal (of whatever isn't collected by the filter or baffles) to the outside. This requires a sufficient air velocity in the hood and ducting. Containment is aided by the hood.

Electric MUA heaters should use controllers to adjust heating to the downstream air temperature. This will be self-correcting for flow rate. The long-term savings might be significant in some markets.

Nonetheless, conventional MUA will be a cost that is unlikely to be lower than that required to purchase and install the hood, exhaust ducting, and fan.

Local codes may be too rigid for alternatives, but if other combustion appliances such as furnaces, water heaters, and gas dryers have their own source of MUA, one could safely avoid having MUA feeding the kitchen, so long as the hood flow rate loss due to reduced house pressure pulling air through cracks was tolerable.

Imaginative solutions, such as the refrigerator-related scheme described earlier in this thread, are worth considering to save cost.

kas

I ordered a 36" with 4 burners and grill. I am planning on getting a 48" Viking hood with 1200 cfm external blower. My cabinet person thought this was overkill but I plan on grilling and wokking a lot so I don't want to be smoked out. (Glad to read that someone else above is doing the same thing.) I also am going to "wing it" on MUA as I have an older house.

Here is my 36" CC with 42" Rangecraft (1200cfm):

We have 6 burners (and wok grate) and opted for a Lodge cast iron grill/griddle. The hood recently sucked up lots of grease from 4 steaks on the Lodge grill (when we ran out of propane on the bbq). I think we needed every bit of the 1200 cfm. Before this hood, my clothes, hair, and everything else in the house would smell like food (I like cooking with garlic!) for days (well until washed that is). The hood makes all the difference - - goodbye permeating food odors!

Hi jsceva,
I got that information at the URL linked below. I didn't verify it directly with the State of California. The iccsafe.org website looks pretty official, so I was assuming that it is correct, but maybe it's not? Did you find some info saying that actually California has not adopted the 2009 IRC, or this part of the 2009 IRC?

BTW I don't mind if you or anybody does want to disagree with me... I don't mean to hold myself out as any kind of ultimate authority... I was just contributing what I had learned via my own (perhaps imperfect?) research.

Best regards,
r.a.

Here is a link that might be useful: Info on IRC (and other code) adoption by state

reluctantartist - Here's the issue, as I understand it. This is NOT a formal legal opinion, so don't rely on it, but...

Calforna's standards for residential construction are contained in the California Residential Code, which is part of Title 24 of the California Code of Regulations (CCR). As of January 2011, for the first time, the CRC does follow the 2009 IRC. It doesn't just do it by reference, however, it adopts specific code sections that contain the language of the model code, sometimes in slightly modified form. More importantly, the California Residential Code ONLY adopts equivalents of the IRC codes up through the end of Part III (("Building Planning and Construction") of the 2009 IRC.

The section of the IRC that addresses makeup air (section 1503.4), however, is in Part 5 of the 2009 IRC ("Mechanical"), within Chapter 15 ("Exhaust Systems"). If you look at the California Residential Code, however, it specifically says "Note: Part V is not adopted. See California Mechanical Code, Title 24, Part 4") This is actually part of the California Residential Code as posted on ICC's own site, as shown in the attached link.

The 2010 California Mechanical Code, is based not on the equivalent sections of the IRC, but on the Uniform Mechanical Code. I does NOT contain any makeup air requirement(s) equivalent to section 1503.4 of the IRC. It does contain provisions for makeup air of gas heaters, commercial kitchens, etc, but the ONLY potentially directly relevant section of the CMC to residential ventilation, based on my cursory initial review, is Section 701.1.4, which states the general proposition that "Where exhaust fans, clothes dryers and kitchen ventilation systems interfere with the operation of appliances, makeup air shall be provided." No specific standards for CFM. The other section of the CMC for residential ranges is section 504 (Environmental Air Ducts) and its subsections, which doesn't address makeup air but does say generally that "Environmental air ducts not regulated by other provisions of this code shall comply with this section . . . Exhaust ducts shall terminate outside the building and shall be equipped with back-draft dampers...Environmental air duct exhaust shall terminate a minimum of three (3) feet (914 mm) from property line and three (3) feet (914 mm) from openings into the building." It also says, more specifically at subsection 504.2 ("Domestic Range Vents") that "Ducts used for domestic kitchen range ventilation shall be of metal and shall have smooth interior surfaces."

I can't find the reference right now, but I remember there is also a provision stating that kitchen exhausts can't issue into "walkways."

Again, this isn't a legal opinion, and I could be wrong. Also, in California as everywhere else local jurisdictions are free to adopt MORE stringent code requirements, so you still need to check with your local agency to make sure they haven't independently adopted a specific makeup air requirement. But in the absence of such a local requirement, I don't think there is any hard and fast CFM-related makeup air requirement in California, at least yet.

Hi jsceva,
thank you so much for the very enlightening post - that is super-helpful info. In light of this I will definitely follow up directly with my city's planning dept to get their take on current requirements.

In your second paragraph you mention "as shown in the attached link"... but I didn't see any link attached to your post...?? Did you mean to attach a link but forgot? Or were you referring to the link in my previous post?

Thanks again for helping set the record straight on this confusing issue.

Best regards,
r.a.

Sorry...forgot to attach the link. It's below.

By clicking on the link for "[2010 California Residential Code� Title 24� Part 2.5 (First Printing) ]" at the top, you can go to a TOC for whole CRC.

Here is a link that might be useful: ICC Page for CRC re

Just spoke to the Building Inspection dept for my city (in Northern California), and the inspector stated that for residential kitchens, there is currently no requirement for make up air, regardless of the hood's CFM rating.

jsceva,
thanks again for speaking up to educate me (and everybody) about the way building code adoption works in California. Really appreciate it!

I wish the info at http://www.iccsafe.org/gr/Documents/stateadoptions.pdf had been a little clearer... they could have annotated the info for CA by saying "adopted in part", or something like that... I guess that's what they were trying to get at with the comment at the top of the chart which says "To obtain more detailed information on amendments and changes to adopted codes, please contact the jurisdiction."

Now comes the even harder part - trying to decide whether or not to implement MUA even though code does not require it. I think we will at least consider doing so in order to leave open the option of increasing our house's energy efficiency in the future by improving its air-tightness. If we put in a medium- to high-CFM fan without MUA, I would be worried about making our house significantly more air-tight in the future.

I suppose we could decide not to install MUA at this time, and plan to retrofit in a MUA solution later, if/when we get around to improving the air-tightness of the house - except that some MUA systems, like the one utilizing the Broan BD4 and BD6 dampers, require a compatible hood as part of an integrated MUA system - you can't just retrofit those dampers into any random hood installation at a later date. Hmm, we'll have to think about this some more.

Best regards,
r.a.

No problems.

FYI, Code revision in California happens every 3 years...so the next time we should see any significant changes is 2013, effective in early 2014.

Also in Northern California and can confirm no MUA required for a 1600cfm blower. The only thing to note is that the local code in San Jose states that ventilation and clearance requirements provided by the manufacturer must be followed. In the Capital specs, they used the standard commercial clearance requirement of no combustible materials 12" to each side (and behind without backguard) and up to 36" above. The picture is misleading because they draw cabinets in that area but my contractor who does a lot of restaurant kitchen work says that's the standard commercial range requirements and means the volume defined by those dimensions must be free of combustibles. He got it signed off but it will depend on your contractor and the inspector to agree on the interpretation of the spec.

On the BTU/CFM ratio: it's a rough and ready correlation, right? As many have posted, hold the pan and its contents constant, and the effect of two different burners, each rated at X BTU, might be very different; and, of course, the performance of the hood will vary according to the geometry of the hood (3D), placement of the hood, geometry (including length) of the duct work, air flow through the kitchen (due to, e.g., lotsa things, including the placement of everything else), etc. And with 6 burners, of course, you might use 5 or 6 occasionally or often, or rarely, or daily, but it's hard to imagine using all of them cranked up to high except in fairly rare circumstances. I'm not sure there's a pressing reason to figure hood requirements differently between Capital, BlueStar, and Wolf, for example, differences in summed max rated burner output notwithstanding.

I've never seen a Culinarian in person, so there's that, but after hemming and hawing between 600 and 1100 cfm for a new 36" BlueStar 6 burner range, I'll say I'm darn glad we went with 1100. Pan seared strip steaks the first night . . . no problem at all. Just did a bunch of burgers for the kids' lunch today because it's pouring and I didn't want to stand in the rain -- everything very nicely contained and nobody in the next room had any idea I was cooking. For most things, the lower settings seem plenty adequate and really pretty darn quiet, but I'm glad to have the higher output for when I want it.