Clinresga once reported here a sound test comparison of his Vent-a-Hood he had at one location and a more conventional system at another location. The VAH was reportedly much louder. A Google search based on this web site's URL and his name may find the thread. As I recall it was a long thread. There are also threads about cleaning VAH that should be evaluated. In my view and that of others, the 18-inch VAH mentioned above is too short front-to-back (depth) for serious cooking. One wants an approximately 24-inch depth to have overlap in depth as well as in width. With the added aperture, more CFM are needed to keep the air velocity up at the baffles (or whatever VAH use in their aperture because they use the squirrel-cage fans to perform one of the functions of baffles -- grease collection. The problem with the CFM capability reported is that it is an apples to oranges comparison. Different things are being measured. It has been my presumption (giving VAH the benefit of the [great] doubt), that the CFM they report is measured for the hood and blower, while that for most fans and blowers is for the fan/blower alone without a hood. In both cases, when ducting is added and the make-up air (MUA) is restricted, the actual flow rate will be significantly less than the number associated with either the VAH or other blowers and fans. What I would recommend for a 3 ft by 2 ft aperture is 6 x 90 CFM actual, and a factor for losses. Maybe (!) this is only 1.2 for VAH (with windows open) and 1.5 for conventional roof-mounted or in-line blowers/fans. It depends on too many factors to just throw out a number that will be valid, but the 1.5 is probably at least reasonably conservative given a decent source of MUA. Under most cooking circumstances, you will be operating the fan at part power because this maximum flow rate won't be needed; the uprising effluent velocity will be lower than assumed for the "90" value. Sound level should be significantly lower. If you like quiet, then a roof fan and in-line sound suppressor with a baffle hood will be best, with most sound apparent to the cook being air turbulence at the baffles. kas

dueceluxe I'm not sure if you ever got an answer to your question, but I'm going to chime in because in 2008 I was in the same boat. We have a 48" BlueStar in a 12' island, with a prep sink located about 48" away, which is where I spend my prep time. Frankly I wish people would focus on answering the direct questions, vs. lecturing about what percentage of prep/cook/cleanup time people "should" be spending in their kitchens, or in which direction they should be facing when doing so. The OP stated they were looking for an island hood for their cooktop, not IF they should be putting the cooktop in the island. For us personally, my prepping and cooking is very intertwined, and we entertain a lot. Ergo, I want to be facing my guests while prepping AND cooking, and not facing my guests during cleanup (THAT sink is behind the prep area against a wall), so the cooktop in the island is what we did and we (and guests) LOVE it and wouldn't go back. It's not for everyone, but it's definitely right for me. Having said all that, yeah, sadly the hood is going to be expensive. We went with a Best by Broan IEX222 51" with a 1500 CFM externally mounted blower. The pros are that the thing will suck up ANYTHING at full speed. The con is that we've had it for 7 years, and unfortunately have gone through 4 control modules or transformers on the thing (everything on it stops working). So nn my frustration I'm now researching replacement hoods, which is going to be $$. It's the price you pay for the style you want. Currently evaluating Cavaliere and Imperial 54" hoods....

Please excuse my intrusion on this thread which I'm not trying to hyjack. I've tried for the last three days to post without any luck. I need help,opinion on converting LP to Nat gas the format has not allowed me to do so???? Instead of hitting the POST button it says NEXT then everything disappears. Very frustrating I have a Viking Range top Model VGRT360-4GSS that I am converting from LP to Nat Gas along with the entire house. It's been extremely frustrating but that's another story for another day. My Mechanical Contractor used the parts I ordered for the conversion. I've never had Nat Gas and know it burns not as hot as LP. However, the burners are rated 15,000 - NG and 13,000 something for LP. The flame looked kind of wimpy but it was all blue and worked at all settings. The next morning I cooked breakfast as usual and found the range top not functioning very well. In frustration I fiddled around trying to adjust the burners. I was able to up the flame a bit but nothing meaningful. Following day I called the parts people explaining my problem and asking if they perhaps sent the wrong parts. No, the orifices are correct size. Then after a long discussion the guy said, Oh that model is a 2001 and there is a pin. If you screw the orifice in too tight the pin restricts the flow. Just back them off and things should work. I failed to ask how much does one back off. I borrowed a box wrench from my framer. He tweaked one burner a bit and left. When I reinstalled the burner and venturi It made a big difference. I've tried to do the same with the others without much luck. They are reamed on so tight I can't get them to budge. My question is, would it be best to uninstall them (if I can get in there and manage to do that) and then reinstall and how much do I screw them in. I know that's probably hard to answer but any help is very much appreciated. I have to make do with this equipment until we do a major kitchen remodel. This is my 3rd time trying to post. It says NEXT then when you hit send, I think there is nothing to send. This time I will make a copy. Anyhow, Thanks for any helpful information and again I apologize for the intrusion Inga

Also keep in mind that you are introducing a source of heat under the induction cooktop. Heat and electronics do not play well together. It is possible that you may shorten the life of the cooktop if you are not careful about the choice you make. This is probably why manufacturers insist upon using like products in this configuration. They may have ways to expel the heat with their own equipment. If I were designing something like this venting would be a priority in my remodel. It would probably involve small fans that had access to cool air to introduce into the cavity for the cooktop and possibly one to expel the warmer air. Preferably outside, however outside the cavity into the kitchen area is preferable than trying to cool with hot air. I believe keeping the electronics cool is key to a long useful life for appliances. Especially ones that produce heat.