I have the Bluestar (Prizer) hood over my 36 RNB with griddle. It has the 1000 cfm remote blower on 8" duct. I would not want any less ventilation than I have, as it is just adequate for when cooking the smokiest meals.

ctycdm, any chance you could send a picture of the Bluestar hood? Trying to decide and still conflicted between the Bluestar and Zephyr. Wish I could compare the two side by side in person, especially to compare the sound. What would you say the sound is like on the different settings?

Ventilation decisions can drive you nuts so don't feel alone. Lots of discussion in numerous GW threads on this topic so dig in if you want. Generally I agree however that 600 CFM won't be enough unless you under-utilize your 6 burner BS, but then why have one? I'd talk to a reputable HVAC person and try to keep an open mind.

As for noise, it is your personal perception that counts. Since you can't compare these hoods side by side, try this. AJ Madison gives sound leves for the Zephyr Tempest II in sones. 6 sones @ 600 CFM and 8 sones @ 1100. Check the wikipedia link below for a definition of sones and a list of every day sounds you can use to compare sone levels. Duct size and blower location (internal vs. remote) make a difference, and even though AJ Madison doesn't say what kind of configuration the sone numbers were measured in, they're at least something.

There are no sone numbers given for the BlueStar hoods, but if you really want to compare, contact their tech support folks and ask. It would be interesting to hear what they say.

Here is a link that might be useful: Wikipedia discussion on sones.

We've given it a lot of thought and decided almost certainly go with the higher cfm, either 1100 or 1200. So now it's just the decision between the Zephyr and Bluestar. They seem relatively similar, although the rep at AJ Madison advised the stainless on the Zephyr will be lighter and the Bluestar would match the rangetop perfectly. The price difference is just under $500, but saving that amount would probably pay for the cost to replace the ductwork. Plus we still have costs to retrofit the counters, cabinets and backsplash... and I still have to find someone to do all this work. My head hurts! LOL

Called Bluestar and she indicated they dont have any sound rating for the hood. So that unfortunately is a dead end. I'm leaning towards the Zephyr since so far no one has presented me with any reason that the Bluestar is far superior. Obviously I'm sure it is superior, just assuming from the price difference. But I need a way to measure that and so far I cant come up with any way to do that.

Mine is an island hood, so this may not help you decide. I had it narrowed down to Modern Aire and Prizer, I felt the fit and finish was superior on the Prizer.

Don't forget Kobe as an option. Quieter than Zephyr and cheaper than Bluestar. The 36 in is powered between the Z and BS, the 42 inch is as powerful as the BS.

RA0236SQB-1 / 36"
RA0242SQB-1 / 42"

See link below

Here is a link that might be useful: Kobe Hood

I keep asking each place about Kobe, but they keep passing over it for some reason. Want to say the AJ rep said Kobe was louder.... But let me check into it.

I haven't bought yet, still in the planning phase of my new build, but I have found build.com is a good place for electrolux and kobe products, I would check them out for the hood. I wish they had Bosch too but alas they do not.

I am so dubious about Bluestar. I have their cooktop and hate the stainless top. It can not be cleaned and burn stains appeared on the stainless top under the castiron griddle. I would be concerned about the stainless quality on the hood.

I have the bluestar hood vent with 1200 cfm. It's wonderful. It's easily able to handle even high heat cooking like woking or searing. It has infinitely variable vent speed (as opposed to just low, med, high) and the same with the lighting.

It's not too bad to keep clean either. Just throw the baffles in the dw every two weeks and wipe the exterior and interior with 409 or another degreaser.

If you're not happy with the SS cooktop with respect to keeping it clean, I'm not surprised. However that's not the fault of the manufacturer. All SS cooktops are hard to clean. It's one of the reasons why I went with the bluestar range with the cast iron open burners. I don't even clean it (except for the occasional big mess) and it looks great. Now, it may not be clean enough to eat off of, but it looks plenty clean.

i haven't purchased my BS yet, but the distributor suggested a 6" larger BS hood. can anyone comment on this? thanks!

Rising effluent expands as it rises, so some cooktop overlap by the hood will improve capture. Effluent "leakage" with a 36-inch hood over a 36-inch cooktop depends somewhat on the adjacent cabinet configuration and which burners you use for the greasiest or smelliest cooking. Allowable leakage depends on your tolerance for odor and grease in the kitchen air.

kas

I'm torn between a Blue Star hood insert for my 48" Blue star range or a Vent-a-hood liner?? The appliance people recommend Vent a hood but I really don't know the difference and can't find anything. SOS :)

I have the Prizer 42" 1200 cfm dual fan hood over my 36" BS range. If you like to wok cook or sear meat at HI heat you wouldn't regret going w/1200cfm. Even all the steam from on open stock pot can be a lot and needs to go away. Combine a boiling stock pot w/a hi heat sear and you'll overwhelm an underrated fan pretty quickly. Those big ranges make big messes in the air, you'll see the 1st time you clean the baffles and the inside of your hood. Even w/my fan on high I still get an oily film on the outside of the hood. You'll be cleaning it as much as you clean the range or more and then a regular deep clean to get the oil out of the baffles (dish washer) and the inside of the hood wiped down. I had mine colored to match the range to no SS to deal with. I love it, it's very noisy but sucking 1200 cfm of air through 2 fans up an 8" pipe makes noise. It's just got the fan button and 2 dimmable lights, like the range it's pretty basic but very functional. I have a 10ft ceiling and the vent pipe goes straight up to the rood w/no bends. Fortunately cooking on high heat is relatively quick so the fan isn't on high for very long.

We also have a Prizer 1200 cfm hood over a 30" Platinum Bluestar. We use the wok once or twice a week and also sear steaks on our cast iron skillet. The hood works well and I don't find the noise too bad - even on high.

As Mistman mentioned - the outside of the hood does get dirty too. but it's very easy to wipe off. BlueStar suggested we use Crud Cutter. Just follow kaseki's advice about sizing - in addition to using a 42" hood on a 36" range remember to also add 3" to the front of the hood too.

Maire_cate how did you add 3" to the front? custom? Or is there a particular standard model that offers this dimension? Could you please share the details?

Separately, I am hearing that the extra 3 + 3 inches on the side are not required for wall mount hoods. Is this correct?

Ria Raj - Our kitchen is small and we did not make the hood wider than the range - we have a 30" wide Prizer hood over a 30" Bluestar. That was one of the reasons we went with 1200 CFM. I'm also fortunate that we only have a 6' run including one 90 degree turn to the outside.

However I think having the extra 3" in the front would have been helpful. When I was looking at the different options I forgot that there are lights in the front of my hood.

I think it was one of the sizes that could be ordered from Prizer. In this photo you can see the lights and the controls for the fan and lights on the front bottom of the hood.

Cooking effluent plumes expand as they rise. Wall hoods use the wall as a plume constraint, and cabinets on the sides may perform that duty for the rear burners. The front burners can only be constrained by side curtains (skirts) that commercial hoods often use. Otherwise, the hood needs to be wider than the pan bases by a few to several inches (depending on hood height) to avoid effluent escaping and not being captured by the hood aperture.

Depending on the range configuration, cooking style, and hood configuration, a 24 inch deep (front-to-back) hood may be adequate. A 27-inch hood will be better. These are overall sizes, and as noted, the lights and controls tend to remove some capture area. For wall hoods with partial side constraints, the front edge of the hood will have a bit more breeze than for an island hood of the same size, so the marginality of a 24-incher will be less noticeable.

All of this depends on the cooking temperature and whether the effluent is mainly water and odor, or grease vapor. Hot rising grease vapor will easily miss the hood aperture if the aperture does not envelop the grease plume. The grease plume can rise at 1.2 m/s, and you will not be running an airflow rate that will yield a hood boundary air velocity anywhere near that.

The previous home owner installed a Vent-a-Hood which we used for many years and finally replaced with a custom-built Modern Aire that has more overhang in the front. We then moved the Vent-A-Hood into the in-law unit. Previously, it had been on a large duct that directly vented outside. It maybe didn't work quite as well as our new Modern Aire, but it overall worked really well. Can't complain at all. Vent-A-Hood makes fine hoods after all.

Now, that we moved it to the in-law unit, it still directly vents outside, but it's on a 6" duct. The loss in performance is mind boggling. We regularly set off the smoke detectors when we cook anything with higher heat. I would strong advise against keeping a 6" duct, if you install a high-end hood. In our case, since it's only the in-law kitchen, I don't feel bothered too much; but I'll probably still fix it at some point. The problem is that the exterior wall is extremely difficult to access. So, this is actually a lot more work than it should be.

Duct diameter should be such that the air velocity in the duct is in the 1000 to 2000 ft/min range, calculating from the actual flow rate. Using too small a duct will not only keep the airflow velocity too high, causing greater impingement grease collection, but reduce the actual volumetric flow rate as M has noticed

Judging from Vent-a-Hood's data, their blowers are even more sensitive to back pressure than axial and centrifugal fan blowers, so duct sizing should tend toward the 1000 ft/min end of the recommended velocity range.

Thanks for the responses. My local dealer tells me that an external blower doesn’t make the vent any quieter. Is this true?

My goal is to get as quiet a range hood as possible. The stove is against an exterior wall. There’s a straight line to the roof in a ranch style home. Modern-Aire recommended a silencer and external blower. What are your thoughts?

Between BS/Prizer or MA hood, which one is better and why?

In my former home we had a remote blower motor mounted outside our home and I think it definitely helped. Our Dacor 36" cooktop had a 1000 CFM downdraft vent which isn't ideal but it was on an island install with no overhead access for venting so the duct work ran underneath the kitchen floor to the outside.

If you read some of Kaseki's other comments on this topic he also frequently recommends a silencer and an external blower. We didn't research other brands of hoods so i can't offer any info there - hopefully Kaseki will weigh in on that topic too.

There are a few sources of noise in a hood ventilation system (and potentially also in a powered make-up air system). The dominant noise when a silencer isn't or can't be used is fan blade tip turbulence noise. Second will be either baffle turbulence noise (more like a hiss), or its counterpart if mesh filtering is used, or duct turbulence noise. Baffle noise domination assumes that the duct is damped on the outside and the air velocity in the duct is not too high. Otherwise duct turbulence noise may dominate baffle noise, and the duct may also rattle passing on blower unbalance vibration noises.

External blower noise is usually lower with a long duct than with a short duct, but one should not expect a really big reduction in noise just because the blower is outside instead of in the hood (for equal volumetric flow rate). (The exception would be a commercial external blower, configured deliberately so that the fan is oversized and the belt drive sheaf ratio is set for a slower tip speed.)

For residential operation, where room for a silencer is available, an external roof blower and inline silencer is the quieter approach, leaving baffle hiss below normal speaking levels at full power. That is my configuration. Part of the duct turbulence noise will also be removed -- that from the duct between the silencer and the external blower.

Fantech silencers are larger than the ducts, e.g., 14 inches in diameter for a 10-inch duct.

http://www.fantech.net/products/fans--accessories/accessories-ventilation/silencers/ld/ld-10-silencer/

They have the general appearance of a motorcycle muffler scaled to a dragline excavator engine. The silencers are also somewhat longish, so if the duct was going to go up into an attic and straight to the roof at the roof edge, it would be necessary to use an angle duct after entering the attic to extend the duct length in the attic to accommodate the silencer, thence use another angle to bring the duct to the roof. Avoid horizontal ducting if possible. Try to make the ducting accessible if possible.

Thank you! Won’t bending the duct twice make it noisier? With the silencer, is this still a better option than plain duct that shoots straight up?

Also, could you please share which stove, range hood and oven you use?

While duct bends will add turbulence, and hence add duct noise, the blower turbulence noise is still dominant, and that is what the silencer is going to mainly suppress. One bend will be on the exterior side and subject to the silencer.

My hood is the largest Wolf Pro Island hood they make, although at the time of purchase Wolf had Independent make their hoods. This hood straddles a Frigidaire 36-inch induction cooktop and a Cooktek induction wok hob. 10-inch duct is used with a Fantech silencer and a Wolf (Broan supplied, possibly with different specs) 1500 CFM (at zero static pressure) roof-mounted blower. There are two roughly 60-degree bends in the duct with the silencer between them. Automotive silencing panels made by Evercoat are used to damp any vibrations propagating down the ducting. (The roof stiffness where the blower is mounted could stand to be augmented.)

A double Wolf oven is on a separate wall over which there are a pair of registers (with replaceable furnace filters) ducted to a separate NuTone roof blower (via an 8-inch Fantech silencer). For many reasons, this is only partially effective as effluent released when an oven door is opened is very difficult to capture in common residential configurations.

For the Wolf hood, estimated flow rate at full power is 900 CFM, or 90 CFM per square foot of hood entry aperture, a value I generally recommend to assure containment of whatever plume content is captured by the hood entry aperture.

Thanks Kaseki for your help. You have a nice set up.

The intake blower for our HVAC is deafening. Do you think I could you use the automotive silencer around the duct to reduce the noise? Its a square shaped duct. I am looking for something to help with this. I consulted two HVAC repair guys on how to reduce the noise and they were of no help.

The set up is this: furnace sits in the garage. The duct travels about 15 feet and bends twice at 90 deg angles.

The automotive quieting panels will damp duct vibration, but not acoustic noise transmitted down the duct. That requires internal sound absorption. I just bought some new Evercoat Q-pad material for a different project. Part. No. 100116 provides six square feet of panels for around $60. This part number is sticky enough for mounting under surfaces and fighting gravity. But for a long large duct they might be a bit pricey.

Someone here quite a while ago recommended http://www.acoustiproducts.us/ for possible use. I haven't used them.

Independent of duct vibration damping, your issue reads as blade turbulence from the blower itself. In that case a silencer that reacts with internal duct acoustic noise will be needed. I think if I were you I would consult Fantech. In my earlier experience, they answered the 'phone. I'm not personally familiar with rectangular duct silencers, so transitions to circular ducting might be needed. A preliminary search of "duct silencers" came up with this link for rectangular: http://iacacoustics.com/hvac-silencers.shtml and they indicate that they are accessible for advice. See also https://kineticsnoise.com/industrial/silencers/rectangular.html

Constructing one's own silencer is not impossible, but a lot of guess work would be needed to choose the configuration. A more thorough Internet search is recommended.

Thank you Kaseki. This is helpful.

I have a 42"Broan over a 36" Bluestar rangetop. It is loud, but it can be turned down. 3 halogen lights are not dimmable, but I never turn them to high. Low is super bright.

As regards to a wider hood...

One problem that I am dealing with is the backsplash, because the hood is wider than the stove. If you only use one backsplash material, everything is fine. It you use a stainless steel backguard and the rest is tile, you need to choose whether to match the width of the hood or the width of the stove. I am matching the width of the stove, so up above, where the stainless steel meets the hood, there will be 3" of tile on the left and 3" on the right. If I matched the hood, the stainless steel backguard would be 3" too wide on either side of the rangetop.

My question is what backguard will you have? As Kaseki can tell you, I have a problem with my Bluestar because I don't have a non-combustible wall behind the rangetop. So I now have a mess to fix to make it follow the codes. Research that too.

While its entirely a design preference, my recommendation based on the experience of cooking with gas: things splutter a few inches to the left and right of stove. Align the steel backsplash with hood width. When you are standing, you mostly see the hood and wall from a few feet away. Stove is less in the line of sight as opposed to backsplash and hood. Keeps things clean this way.

In our case, we replaced the drywall with cement board - maintaining the same thickness in the wall overall. Then we also put tiles in front of this cement board.