"David Hare-Scott" > wrote in message
...
> I am in the process of setting up a new kitchen and I am getting
frustrated
> about range hoods. I want a range hood that really works (ie extracts
> smoke, smells and steam efficiently) but I cannot afford to pay the earth.
>
> Appliance shops deluge you with sales bull and explain nothing. You can
get
> a hood from $200 to $2000. Some of the larger and fancier ones have more
> stainless steel and bells and whistles but some look just the same and
have
> a price tag twice (or half) as much. When asked to explain the difference
> you get "the more expensive one is better" if you ask better in what way
> exactly you get told about features but not performance. I can make my
own
> jugements about ease of cleaning and if I need frisbees on the thingajig
or
> gold plated whatsernames.
>
> I have looked at professional cooking gear web sites but so far it seems
> that you have to have qualifications in air conditioning engineering to
> follow their specs and most of the products assume a restaurant sized
> operation.
>
> One web site recommends that the hood be able to extract between 6 and 12
> times the volume of the room per hour. That is you turn over the air
every
> 5 to 10 minutes, this seems reasonable to me.
>
> Does anybody have any views on that? Under what circumstances would the
> upper or lower rate be appropriate?
>
> How else might one assess the required rate?
>

You might ask over at rec.food.equipment. This is a much discussed topic.
Most people agree that the hood should be larger than the cooking surface.
The capacity in CFMs is dependant on the BTUs and the type of cooking. If
you are going to grill, then you should error on the larger end. For
typical cooking on a typical residential range you probably need between 600
and 1200 CFM. If your house is new and very tight, you can create dangerous
downdrafts in chimneys (fireplace, water heater, furnace,) if the hood is
too large and you don't have a source of make-up air. One rule of thumb
that I have seen is that you need 10 CFM per 1000 BTU of output from the
stove. On thing to keep in mind is that the ratings for hood drop as you
increase the length of duct and for each change of direction. There is also
a drop associated with the resistance of the damper that terminates the
duct.