Range hood, fan size..

Chuck said:

Going to have to install range hood with outside exhaust (through the
roof) this weekend...
I'm having new roof installed and want this in prior to new roof so
I'm pushed for time.. My current hood is just a "blow steam and grease
in the top of your head while cooking type...

My length of ducting is well below the max for either.. 7ft of 7"
round duct with no turns. Possibly needing a rectangular to round
adapter depending on model of hood
It's a 30" hood.. I see some with 220 cfm and 390 cfm for twice the
money.. Is the 390 cfm needed?
$380. for the 390 cfm
$130 for the 220 cfm
I wouldn't mind the 390 cfm as much if it's strong enough to pull in
fresh air if something get's "funky" smelling.. and I open a couple
windows..for a few minutes though I know it's not a whole house fan...
I guess it's just sticker shock.. Nice hood and fan for %70 of cost of
new standard range would cost..

You have NO IDEA how expensive ventilation can be if you're in sticker
shock over less than $400. Do your calculations.... will this hood
move enough air? Kitchens require a minimum of 15 air replacements
per hour.
--

Practice safe eating. Always use condiments.

when i bought my husband the VIKING he has always wanted, it came with
special instructions on the kind of exhaust hood it needed.

--

BUSHISM
"As you can possibly see, I have an injury myself-not here at the hospital,
but in combat with a cedar. I eventually won. The cedar gave me a little
scratch."-
......After visiting with wounded veterans from the Amputee Care Center of
Brooke Army Medical Center, San Antonio, Texas, Jan. 1, 2006

"Chuck" <[email hidden]> wrote in message
news:[email hidden]...

Quoted message said:

Going to have to install range hood with outside exhaust (through the
roof) this weekend...
I'm having new roof installed and want this in prior to new roof so
I'm pushed for time.. My current hood is just a "blow steam and grease
in the top of your head while cooking type...

My length of ducting is well below the max for either.. 7ft of 7"
round duct with no turns. Possibly needing a rectangular to round
adapter depending on model of hood
It's a 30" hood.. I see some with 220 cfm and 390 cfm for twice the
money.. Is the 390 cfm needed?
$380. for the 390 cfm
$130 for the 220 cfm
I wouldn't mind the 390 cfm as much if it's strong enough to pull in
fresh air if something get's "funky" smelling.. and I open a couple
windows..for a few minutes though I know it's not a whole house fan...
I guess it's just sticker shock.. Nice hood and fan for %70 of cost of
new standard range would cost..
Thanks..
Chuck (in SC)

Chuck said:

Going to have to install range hood with outside exhaust (through the
roof) this weekend...

Why through the roof, why would you want to cut a big hole in your nice
brand new roof? If possible you're always better off with a
residential exhaust exiting through a side wall with the ductwork
aiming downward. My exhaust duct goes up through a kitchen cabinet and
into the attic where it travels horizontally about eight feet and exits
downward through the soffit... this arrangement also makes it easy for
me to maintain the system myself, I can easily remove all the ductwok
from inside the attic and take it outside to clean if necessary.
Ductwork exiting a peaked roof tends to suffer from down droughts as
even a slight breeze is amplified by the venturi effect as it travels
over a pitched roof. For such a system to work properly you'd need a
vent pipe that extends at least three feet higher than the roof ridge,
very ugly. Those flush mount mushroom looking thingies don't work very
well on many counts, the exiting exhaust grease will stain the roof
too, badly... within a year you'll have a big ugli stain on your nice
new roof, and everytime it rains that stain will expand and also run
down to the eves... this won't look pretty. You don't want to place
any extra holes in a roof, just another place for a leak to develop.

"Chuck" <[email hidden]> wrote in message
news:[email hidden]...

Quoted message said:

Going to have to install range hood with outside exhaust (through the
roof) this weekend...
I'm having new roof installed and want this in prior to new roof so
I'm pushed for time.. My current hood is just a "blow steam and grease
in the top of your head while cooking type...

My length of ducting is well below the max for either.. 7ft of 7"
round duct with no turns. Possibly needing a rectangular to round
adapter depending on model of hood
It's a 30" hood.. I see some with 220 cfm and 390 cfm for twice the
money.. Is the 390 cfm needed?
$380. for the 390 cfm
$130 for the 220 cfm
I wouldn't mind the 390 cfm as much if it's strong enough to pull in
fresh air if something get's "funky" smelling.. and I open a couple
windows..for a few minutes though I know it's not a whole house fan...
I guess it's just sticker shock.. Nice hood and fan for %70 of cost of
new standard range would cost..
Thanks..

A 220 cfm is fine if you also install an air source near the stove (a run
from the outside to the appliance, usually on a side other than the vent
side, to provide make-up" air, with a "trap" in that line.)
If you use leaks in your house and the furnace air intake to get make-up
air, then the larger size is usually needed, since you won't be moving
anywhere near the rating because of extra "head loss".
(think four cubic feet vs six cubic feet per second in a 7" pipe - a LOT
of air IF there is air available over the stove. A vented stove typically
has around 16 cu ft over it, and a typical kitchen has 800 cu ft - and then
consider that if the fan actually exhausts 390 CFM, it has sucked ALL the
air out of the kitchen EVERY two minutes. Obviously, it doesn't do that if
outside air is not provided)

It is very important to make sure that your fan does not suck air
backwards through your heater and furnace vents - in other words, fans that
exhaust to the outside will draw the-air-they-exhaust from any opening - and
a vent pipe for a furnace or water heater, and a fireplace chimney, are
openings to that fan.

The make-up and exhaust-volume sizes should be sized together.

fwiw....

Quoted message said:

Chuck (in SC)

Sheldon said:

Chuck said:

Going to have to install range hood with outside exhaust (through the
roof) this weekend...

Why through the roof, why would you want to cut a big hole in your nice
brand new roof? If possible you're always better off with a
residential exhaust exiting through a side wall with the ductwork
aiming downward. My exhaust duct goes up through a kitchen cabinet and
into the attic where it travels horizontally about eight feet and exits
downward through the soffit... this arrangement also makes it easy for
me to maintain the system myself, I can easily remove all the ductwok
from inside the attic and take it outside to clean if necessary.
Ductwork exiting a peaked roof tends to suffer from down droughts as
even a slight breeze is amplified by the venturi effect as it travels
over a pitched roof. For such a system to work properly you'd need a
vent pipe that extends at least three feet higher than the roof ridge,
very ugly. Those flush mount mushroom looking thingies don't work very
well on many counts, the exiting exhaust grease will stain the roof
too, badly... within a year you'll have a big ugli stain on your nice
new roof, and everytime it rains that stain will expand and also run
down to the eves... this won't look pretty. You don't want to place
any extra holes in a roof, just another place for a leak to develop.

I've not seen the soffit fixture... Did you use a "wall" fixture there
or do they make one just for exiting soffit?... I prefer this
option...
Chuck (in SC)

Chuck said:

Sheldon said:

Chuck said:

Going to have to install range hood with outside exhaust (through the
roof) this weekend...

Why through the roof, why would you want to cut a big hole in your nice
brand new roof? If possible you're always better off with a
residential exhaust exiting through a side wall with the ductwork
aiming downward. My exhaust duct goes up through a kitchen cabinet and
into the attic where it travels horizontally about eight feet and exits
downward through the soffit... this arrangement also makes it easy for
me to maintain the system myself, I can easily remove all the ductwok
from inside the attic and take it outside to clean if necessary.
Ductwork exiting a peaked roof tends to suffer from down droughts as
even a slight breeze is amplified by the venturi effect as it travels
over a pitched roof. For such a system to work properly you'd need a
vent pipe that extends at least three feet higher than the roof ridge,
very ugly. Those flush mount mushroom looking thingies don't work very
well on many counts, the exiting exhaust grease will stain the roof
too, badly... within a year you'll have a big ugli stain on your nice
new roof, and everytime it rains that stain will expand and also run
down to the eves... this won't look pretty. You don't want to place
any extra holes in a roof, just another place for a leak to develop.

I've not seen the soffit fixture... Did you use a "wall" fixture there
or do they make one just for exiting soffit?... I prefer this
option...

It was there when I moved in. The hood is a Sears Kenmore, works very
well, has a dual level lamp and the fan is on an infinite rheostat... I
typically use it within the lowest range. There are aluminum mesh
filters that I send through the dishwasher as needed. I've no idea who
did the duct work or who makes the soffit unit... it's quite possible
the previous owner did that part himself as he owned (still does) a
large machine shop.

Sheldon said:

Chuck said:

Sheldon said:

Chuck wrote:
> Going to have to install range hood with outside exhaust (through the
> roof) this weekend...

Why through the roof, why would you want to cut a big hole in your nice
brand new roof? If possible you're always better off with a
residential exhaust exiting through a side wall with the ductwork
aiming downward. My exhaust duct goes up through a kitchen cabinet and
into the attic where it travels horizontally about eight feet and exits
downward through the soffit... this arrangement also makes it easy for
me to maintain the system myself, I can easily remove all the ductwok
from inside the attic and take it outside to clean if necessary.
Ductwork exiting a peaked roof tends to suffer from down droughts as
even a slight breeze is amplified by the venturi effect as it travels
over a pitched roof. For such a system to work properly you'd need a
vent pipe that extends at least three feet higher than the roof ridge,
very ugly. Those flush mount mushroom looking thingies don't work very
well on many counts, the exiting exhaust grease will stain the roof
too, badly... within a year you'll have a big ugli stain on your nice
new roof, and everytime it rains that stain will expand and also run
down to the eves... this won't look pretty. You don't want to place
any extra holes in a roof, just another place for a leak to develop.

I've not seen the soffit fixture... Did you use a "wall" fixture there
or do they make one just for exiting soffit?... I prefer this
option...

It was there when I moved in. The hood is a Sears Kenmore, works very
well, has a dual level lamp and the fan is on an infinite rheostat... I
typically use it within the lowest range. There are aluminum mesh
filters that I send through the dishwasher as needed. I've no idea who
did the duct work or who makes the soffit unit... it's quite possible
the previous owner did that part himself as he owned (still does) a
large machine shop.

Thanks..
Chuck (in SC)