barjohng - thank you for the recommendation. I had never heard of this brand, I'll check into it. The price is very reasonable, so I hope it will work.

Cheryl

I have done a bit more research. Here is what I have learned. Other reputable dealers don't recommend it because it is Chinese made of inferior stainless (not 304). It looked good and the price looked very good. I have since looked at the Kobe, Imperial, Brillia, and VentAHood. The Brillia 600CFM with filter baffles in my 30" 10" High runs $598. It is made by Kobe but a lesser quality version. The imperial is 735CFM dual blower 10" high runs $699. The Kobe 10" high 30" 640CFM runs $809 and the 9" high VentAHood 600CFM with dual blowers runs $1022.

The VentAHOOD is the onl design that does not use conventional baffle or mesh grease filters. They call their lung "Magic Lung Bowers" and it is a really unique and interesting design. Even though rated at 600 CFM, because it is isn't pulling through filters it achieves a true 600CFM out where the others get less due to the restrictions caused by moving the air through the filters. It is easy to clean and very quiet. Granted it is $400 more than the least costly and $200 more than the Kobe but from what I can see it appears to be worth the price difference. Higher CFM's are available but not in the 30" model.

If anyone else has some experience or knowledge to share I would love to hear it before I make a buy decision.

A quick way to compute the ventilation needs is to add the BTUs from each burner to get a total BTU and divide by 100. Using the Bluestar 30" RNB range as an example you have two 22K burners, 1- 15K burner and 1 - 9 K burner for a total of 68,000BTU. Divide by 100 and you have 680CFM.

barjohng - we looked at Vent-a-hood but to get 600cfm, we would give up the cabinet above since there are 2 blowers, making a 8" minimum duct which has to be vertical. We would also have to put in much bigger ducts in the wall in order to draft this volume of air.

If you search on vent-a-hood you'll see some strong opinions. That may help your decision.

I've also been doing more homework, and I think Kobe may be it. They have 800cfm hoods which vent horizontally, so we don't have to go into the cabinet. They also connect to 3.25" x 10" ductwork.

DH has looked at the existing ducts and said they won't work. They were installed in a bizarre fashion with multiple bends, going into the bottom cabinet and back out. Basically the number of 90 degree bends is about 6! Crazy.

We're going to have to put new ducts in which go vertically through the roof, but that makes the run efficient. From what I've read, the Kobe is quiet, and I've seen few complaints.

For induction, a rough calculation of cfm is 200cfm per foot of cooktop. For our 36" cooktop, that's 600cfm. We have a lot of power (7600W total, not boosted; another 1200W with boost), so I think 800cfm is desirable.

Cheryl

I was speaking with the Bluestar rep yesterday (he used to be a ventilation guy) and he said a quick an easy formula is to take the total BTU's of the range top and divide by 100. Just so you know, VAH does offer a back vent option that transitions from the 8" to a rectangular, but not 3.25 x 10 as that will significantly reduce your effective CFM. An 8" round gives you 50 sq inches of cross sectional area (pi x r Squared). Your duct will only give you 32.5" so that is a big drop. About the same as a 6" round duct. See my comments in the long thread on the VAH.

I know how to convert from BTU to required cfm, I wanted to give the equivalent for induction which is quoted in watts. I just realized my error in the previous post - the total power in our induction cooktop is 11600W, with another 1200W on boost.

It was venting that convinced us to go with induction. For the BS cooktop or rangetop we wanted, we would have needed 900cfm minimum, but 1200 cfm was recommended. This would have taken the entire cabinet out and called for a major drywall/plaster/roofing job. We weren't prepared for this kind of upheaval, when induction seemed so much more attractive.

The VAH "conversion" is a 45 deg bend from the vertical vent, so still requires at minimum 8" of the cabinet above. I don't see any benefit in the VAH option for us especially with the approximately $500 extra cost.

Our main indecision is between Kobe and Zephyr, but the fact that Kobe offers the rear vent may be the deciding factor. I haven't seen anything else that is more appealing (yet).

I didn't realize you were talking about an induction range. I have one (Electrolux) in my Galveston Beach house and it really doesn't require much in the way of ventilation since the heat generated is directly into the pan.

I spoke to Electrolux before purchasing my induction range which was being placed in a peninsula. I was told no hood was needed. I figured I could always put one in later so I followed the advice. So far - no issues, although I have not yet done any stir frying or pan frying.

Unfortunately a lot of my cooking is stir frying, or searing. We've had our induction cooktop less than a week and twice already I've filled up the kitchen with smoke and food smells. We definitely need a hood or winter will be pretty awful.

jade

Glad you decided to reconfigure - for each bend in ducting you loose cfms- 6 total would render a high efficient one to practically useless.

Have you checked out Zephyr - we have the Typhoon and are very pleased - now 6yrs old

Here is a link that might be useful: zephyr under cab

jejvtr - thanks for the recommendation. Zephyr makes so many products, I was lost in the specs! The Typhoon sounds like a good option for us, so we will definitely check it out.

Cheryl

After reading many comments in this forum and visiting several dealers, I decided to purchase the Modern Air unit. I'm still not sure it is better than the VAH unit and the one salesperson that I spoke with that had it in her home said that she loves hers. Says it is quieter than the Modern Air (they sell both in the store) and very easy to clean provided that you start it running before you start cooking.

I looked at Zephyr, Kitchen Aid, Wolf and Kobe but decided that for the money ModernAir offered the best combination of quality, noise level and CFM performance. It will be a little while before it is installed and I can actually test it.

barjohng, which Modernaire did you select and how much did it cost? We are looking at them, but 600 cfm for us would cost over $2K. Does not fit our budget, no local distributors, and factory refers us to distribs that are 500-700 miles away so it's all done by phone. Thanks

Trevor sells modern air (Eurostoves) in Beverly, Mass. He is a presence on GW and very helpful. Give him a call. I believe there are models under 2K.

There's
a fair amount of interest in Kobe brand so I thought I'd post my
experiences.

I
bought and installed a Kobe Island Range Hood (model IS2436GSB) late
in 2006. It has performed well until November 2011 when the lights
stopped working. The bulbs were OK, so I called Kobe and talked to a
somewhat unhelpful technician. He couldn't tell me much and there is
little electronic info in the user's manual (what is there is really
confusing and inaccurate) , but the problem was likely in the LCD
panel, the "processor board" or the transformer. The board
was the most likely culprit, so $110 and 3 hours later, I replaced it
to find it didn't help. (There were other things that didn't work
besides the lights)

Long
story short, between 2006 and 2011, Kobe made 3 versions of this
hood, each with a different electronic design. Since the LCD (display
on front) was not available anymore, they offered me a "discount"
on an entirely new unit.

Bottom
line: nice looks, but poor design, poor construction,
poor support and poor
repair possibilities. Stay away from this company.