I got this one from futuro, and I loved it. I probably should have gotten a wider one, but it was sufficient for a 5 star cooktop with 4 burners and a griddle.
price was good and installation didn't seem to present any problems or I'm sure the guys would have told me. It was an island hood, but if it was wall mounted, I think nothing would have escaped it.
HTH.
Lisa Clarkson

Here is a link that might be useful: Futuro Island Hood

Ditto on the Futoro hood. Costs less and the performance is better.

Thanks for the info, greatly appreciated!

anna_b

Did you ever hit the nail on the head. We are looking a replacing an island cook top and wall oven by removing the wall oven and 30 inch cabinet and replacing it with some sort of dual fuel or all gas slide in range. We do a lot of wok cooking, and the current downdraft gas cooktop we have is about the worst invention anyone has ever come up with.

We are punching through the wall into the garage so we can have a hood over the range. So far we have been able to find out the deeper the hood, the better. So we are looking at no less than 24 inch deep, because it captures the fumes. We have a similar open floor plan, so any fumes must go.

We have been told if we want CFM, an inline or external blower is the way to go. The more powerful fan is moved away from the kitchen (in the garage for us) and is less noisy, but more powerful.

Since we do a lot of Asian cooking, we will be running high speed, so baffles will be better than mesh, but to be aware that baffles depend on high speed.

Finally we have been told that once you start getting to 600 CFM and above, you need to start thinking about replacement air, or all that technology will not work. I had never heard of replacement air, but apparently a high CFM hood can lower the barometric pressure in a room, and the attendant decrease in efficiency results.

Unless we want expensive replacement air systems, we are advised to crack a window, and let the hood run for a couple of minutes to establish a balanced flow of replacement air before we start cooking. Who knew?

Needless to say, 24 inch hoods are expensive, baffles are expensive, inline or external fans are expensive, putting new ductwork through the kitchen wall into the garage and out the structure is expensive. Sigh

We jokingly said, now that we are getting rid of the cooktop with the downdraft, we can use the old exhaust system as a replacement air source. Link the hood fan switch to another fan that draws in air from the outside and vents it under the island...the crazy things you come up with at midnight. I think we are going to go with the cracked window once we figure out how many CFM, etc.

Let us know what you find out. It would seem to us that 600 CFM is more than adequate for a 30 inch higher end consumer range such as a Bosch, GE Profile or similar. All those others, Dacor, BS, Viking etc are too expensive for us, especially since we forecast spending all the money designing and installing the hood!

Unless you live in places like Minnesota where makeup air is required by code for anything greater than 300 CFM, I believe, you can generally go up to 600 CFM without the need for makeup air, particularly if your house isn't airtight. Above 600 CFM, you not only run the risk of loss of efficiency but you run the risk of backdrafting your furnace, for example. Cracking a window is certainly one method of providing makeup air but it may not be practical in a cold climate.

Keeping interior pressure constant has several benefits. As noted above, fireplaces and furnaces can backdraft. The fan itself will loose some flow rate with negative relative house pressure.

If a fireplace is not an issue, then a separate feed to the furnace is possible in some circumstances to avoid backdrafting. I am aware that oil furnaces, for example, have such kits available.

If the weather will support having windows open, then that may be sufficient. At the 300 cfm level, most houses leak enough air to allow ignoring the problem. Otherwise, a source of exterior make-up air (MUA) is needed. Opening a window is considered a passive source of MUA and may suffice. It certainly is the economical solution where feasible.

If it is too cold to open a window, then it is too cold to use unheated MUA. This means that a rather large roof or side fixture is needed to let in air without rain and without significant static pressure loss, a fixture mounted or in-line fan is required, a heat exchanger is required, a source of heat for the heat exchanger is needed (one could use an extension to a hydronic system or use electric elements, or one of several other possibilities), and a diffuser and ducting are required to transport and dump the air into a room. The intake fan may need to be on a pressure sensing control loop.

The basic picture is similar to a kitchen hood operating in reverse but with the complication of air heating. (Use of an air conditioning system to distribute the air can be considered if the heated air stays warm during transport. This may be the case where heat pump sytems are used for heating and cooling.)

In order to not disturb the airflow into the exhaust hood so it collects all the cooking effluent it can, the MUA should enter the house volume well away from the hood. Ideally, the flow from MUA to hood should be over a large area at low velocity.

My setup uses a large Wolf island hood (actually made by Independent) with 1500 cfm (at zero static pressure) Wolf (made by Broan) exhaust fan. The flow around the hood seems gentle at full fan power. However, my MUA system is not yet installed. If I move from the hood to a doorway in the path to where there are open windows, I can feel a considerable breeze flowing toward the hood.

Calculate your kitchen volume (in cubic feet) and divide by the cfm you intend to use, and you will see that the kitchen volume is moved out of the house in a very short time, hence the need for MUA. However, a better (but crude) assumption is to use 2/3 of your rated cfm, because the exhaust fan will not be operating at zero static pressure.

I guess the lesson is that if one wants semi-pro cooking capability, one needs semi-pro ventilation and MUA capability.

kas

"We jokingly said, now that we are getting rid of the cooktop with the downdraft, we can use the old exhaust system as a replacement air source." -- chas2rl

Ha ha! I can so relate to this!! LOL!

kaseki,

Great info. Thanks!

You are all doing your homework. Thank you, Anna Bannana.

It is amazing how many consumers buy useless badly designed hoods, largely because they look good and they are what a proper kitchen requires, even when they are little more than mute sculptures.

Why even bother buying a hood if the kind of cooking performed - - little wok or no searing - - hardly needs anything more than the gentle movement of a spring breeze?

That is not the case here however.

Kaseki has does us a great service as well.

I estimate the cubic footage of our redesigned kitchen in New England at about 1,100. It is now a room of its own, with two doors and one window. Adjacent to each door are exits to the house, within about a dozen feet. The kitchen window is about 6 feet from the proposed hood.

The heating steam is baseboard hot water. There is no central air conditioning. There is a working fireplace about 15 feet away in a separate room. For most of the year the climate is temperate enough so cracking open the windows and doors should not be a problem. On those occasional sub zero days I simply won't do much wok cooking. Stews seem to be in order then.

I would imagine that three points of replacement air access ahould be enough to handle the proposed 600 CFM exhaust system.

Please let me know if this makes sense.

I concur. The critical behavior is to be sure an MUA path is open before starting a fire in the fireplace. If you smell any smoke when cranking up the kitchen exhaust, be sure to open the windows further.

kas

What size is your duct?
What shape canopy have you planned for?

Here is a link that might be useful: Duct size, canopy shape, cfm's

Since you are planning a kitchen remodel, I would move heaven and earth to try to get your cooking area against an outside wall. I certainly wish I had. Our area is on a pennisula, which for the sake of exhaust works as an island so we had to get an island hood. Well that snowballed. I wanted to get something with fairly decent CFM's at a reasonable price that was also attractive...enter our Futuro hood. I must say that I am satisfied with it's performance given the area that it is in. However, our furnace guy let our builder guy know that we needed to have a make up air system which would bring in regular air up until a certain outdoor temperature and when below that temperature, the heated coils would kick in. Add $3500(cdn) to that equation. When that make up air system comes on it sucks up so much juice that I can see the lighting in my kitchen dim slightly and see the lighting in my refrigerator pulsate. As the Futuro has 4 power settings I had the furnace guy and an electrician wire it so that the MUA would only come on at the highest setting. Well we've been our new kitchen coming onto a year soon and the system as started coming on at the #3 setting and on really hot days at the #2 setting(the warm air that it blows in is not welcome at all).
I've contacted the furnace guy to come and fix it but we are not sure things will work out with the sensor gadgets. I have to admit, I hate it when I hear something has a 'sensor', as I 'sense' future problems.
So the long and short of it is, if you can make your exhaust system simpler by venting to the outside directly, I would do that. You'll be able to get by with a less powerful hood and save that way as well.