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Home > Archive > Building and Construction > June 2007 > Is this type of fan appropriate under roof vents in ceiling?
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Is this type of fan appropriate under roof vents in ceiling?
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| I am going to install a whole house fan to exhaust hot air out of the rooms
on the top floor , and while I'm at it I'm thinking of installing fan(s),
most likely one (1). in the roof itself to exhaust the air right out from
over the ceiling of those rooms. Get it out of the rooms, into that upper
area; then why not right out of that area, a hot box.
I have looked into the packaging of one of these fans at HomeDepot. Its
just a 15"! (x6"?) circular shroud, and it is to be mounted anywhere- theres
no flush mounting or anything, just some metal clips. The pic in the manual
shows it mounted so it is blowing Horizontally - out of a louver vent
mounted on the front of an "attic" - above the ceiling & below the roof, at
the front of the pictured house.
I am thinking I would want to mount a fan under the existing vents on the
roof, pointing up and out these vents. I do not want to screw around with
the shingles outside. I've got 2 of the std. size approx 12"x12" vents,
with screen inside. These vents are only about 7' apart, on adjacent parts
of the roof, at the rear. The foof is about 10' x 20'. I am thinking of
wiring a switch inside, beside the whole house fan switch (maybe pull
cord?), and using metallic shielded cable.
Can I use this type of fan, mount it just below the vent(s) facing up?
Will I need to worry about a seal to the vent to create a push vacuum?
Do I need to worry about the size(s)/cfm carefully of the fan(s) wrt the
whole house fan?
Theres soffit venting 360, and 2 vents, need I cover (and seal) both (2)
vents with fans?
http://www.homedepot.com/webapp/wcs...uctId=100055092
the "interior roof" fan
http://www.homedepot.com/webapp/wcs...dkey=THDSiteMap
the whole house fan
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| |
| trader4@optonline.net 2007-06-26, 1:25 pm |
| On Jun 26, 1:06 pm, "bent" <b...@rogers.com> wrote:
> I am going to install a whole house fan to exhaust hot air out of the rooms
> on the top floor , and while I'm at it I'm thinking of installing fan(s),
> most likely one (1). in the roof itself to exhaust the air right out from
> over the ceiling of those rooms. Get it out of the rooms, into that upper
> area; then why not right out of that area, a hot box.
When a whole house fan is used, its drawing cool outside air into the
house from open windows and pushing air from the upstairs ceiling into
the attic and then out through the attic vents. The air going into
the attic from the house is maybe 80 deg? That's not a hot box and
in fact the attic should be quite cool and with proper insulation,
doing anything else with powered fans isn't going to do you any
measurable good.
With the whole house fan, I would be concerned about having enough
attic venting to support the volume required. And if you don't I'd
solve it with a ridge vent, or maybe another gable vent, not by trying
to turn regular roof vents into powered ones.
>
> I have looked into the packaging of one of these fans at HomeDepot. Its
> just a 15"! (x6"?) circular shroud, and it is to be mounted anywhere- theres
> no flush mounting or anything, just some metal clips. The pic in the manual
> shows it mounted so it is blowing Horizontally - out of a louver vent
> mounted on the front of an "attic" - above the ceiling & below the roof, at
> the front of the pictured house.
>
> I am thinking I would want to mount a fan under the existing vents on the
> roof, pointing up and out these vents. I do not want to screw around with
> the shingles outside. I've got 2 of the std. size approx 12"x12" vents,
> with screen inside. These vents are only about 7' apart, on adjacent parts
> of the roof, at the rear. The foof is about 10' x 20'. I am thinking of
> wiring a switch inside, beside the whole house fan switch (maybe pull
> cord?), and using metallic shielded cable.
>
> Can I use this type of fan, mount it just below the vent(s) facing up?
> Will I need to worry about a seal to the vent to create a push vacuum?
> Do I need to worry about the size(s)/cfm carefully of the fan(s) wrt the
> whole house fan?
> Theres soffit venting 360, and 2 vents, need I cover (and seal) both (2)
> vents with fans?
>
> http://www.homedepot.com/webapp/wcs...tDisplay?sto...
> the "interior roof" fan
>
> http://www.homedepot.com/webapp/wcs...tDisplay?id=...
> the whole house fan
>
> ----== Posted via droptable.com - Unlimited-Unrestricted-Secure Usenet News==----http://www.droptable.comThe #1 Newsgroup Service in the World! 120,000+ Newsgroups
> ----= East and West-Coast Server Farms - Total Privacy via Encryption =----
| |
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| the entire 10', 10', 20', 15' x ~6" soffit is by area 1/3 punch vented, then
the 2 ~12"x12" vents
> With the whole house fan, I would be concerned about having enough
> attic venting to support the volume required. And if you don't I'd
> solve it with a ridge vent, or maybe another gable vent, not by trying
> to turn regular roof vents into powered ones.
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| |
|
| the air, if effeciently exchanged may be less, but I've been reading
http://www.homedepot.com/webapp/wcs...dkey=THDSiteMap
and the air in there could be 150 it seems, besides I have dark brown
shingles
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| |
| Chieh Cheng 2007-06-26, 5:25 pm |
| > I have looked into the packaging of one of these fans at HomeDepot. Its
> just a 15"! (x6"?) circular shroud, and it is to be mounted anywhere- theres
> no flush mounting or anything, just some metal clips. The pic in the manual
> shows it mounted so it is blowing Horizontally - out of a louver vent
> mounted on the front of an "attic" - above the ceiling & below the roof, at
> the front of the pictured house.
I bought three 20" temperature controlled box fans ($20 each). Mounted
one over the louver vent on the front side of the garage. Mounted the
other two on the louver vents on one side of the house. The blow hot
air out, and hopefully sucks cold air into the attic from the other
sides of the house. So far it seems to work quite well. Way more
energy efficient that using the AC all the time. See my more detailed
write-up:
http://www.gearhack.com/Forums/Disp..._the_Attic.html
Chieh
| |
| Chieh Cheng 2007-06-26, 5:25 pm |
| On Jun 26, 2:59 pm, Chieh Cheng <chiehch...@gmail.com> wrote:
>
> I bought three 20" temperature controlled box fans ($20 each). Mounted
> one over the louver vent on the front side of the garage. Mounted the
> other two on the louver vents on one side of the house. The blow hot
> air out, and hopefully sucks cold air into the attic from the other
> sides of the house. So far it seems to work quite well. Way more
> energy efficient that using the AC all the time. See my more detailed
> write-up:http://www.gearhack.com/Forums/Disp...ome/Cooling_...
Oh, one more thing. I forgot to mention that if you are going to put
in a whole house fan, then you probably don't need powered fans in the
attic. The whole house fan will create positive pressure in the attic,
forcing air out the vents. It would create negative pressure in the
living space to draw air in. You just want to make sure to keep all of
these passages open when you turn your whole house fan on.
Chieh
| |
| trader4@optonline.net 2007-06-26, 8:25 pm |
| On Jun 26, 4:43 pm, "bent" <b...@rogers.com> wrote:
> the entire 10', 10', 20', 15' x ~6" soffit is by area 1/3 punch vented, then
> the 2 ~12"x12" vents
Sounds like you're OK with the soffit venting, but doesn't sound like
adquate exit venting to keep the attic cool without the whole house
fan, which is what I'd be concerned about. I'd get more venting,
most likely a ridge vent which is cheap and easy to install. But if
you have a whole house fan going and that is your main concern, with
all the soffit venting and the two other vents, there is probably
enough venting for it to work. In other words, I'd forget about
adding powered fans to the two roof vents. At least I'd put the whole
house in first and see how it works without taking on more work and
putting in more fans that use power.
>
>
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| |
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| On Tue, 26 Jun 2007 14:06:11 -0400, "bent" <bent@rogers.com> wrote:
>I am going to install a whole house fan to exhaust hot air out of the rooms
>on the top floor , and while I'm at it I'm thinking of installing fan(s),
>most likely one (1). in the roof itself to exhaust the air right out from
>over the ceiling of those rooms. Get it out of the rooms, into that upper
>area; then why not right out of that area, a hot box.
Usually whole house fans are used after 6 pm or after whatever time
the outside has cooled off enough that it won't warm the inside of the
house to suck in the outside air. I guess that could be as late as 9
but I'm not sure.
Usually roof fans go on between 9 and 12 in the morning and off
between 5 and 8, depending on how sunny and hot it was during the day.
I'm a big fan of roof fans, but normally whole house fans have enough
power to get their air into the attic and beyond, unless I guess there
is quite a restriction getting out of the attic. Soffitt vents which
are intake vents when using natural convection and roof fans would
easily function as exit vents when there is a whole house fan, but I
don't know nearly enough to know if your soffits are big enough for
this.
I like roof fans if the attic is conducting it's heat to the second
floor, but regardless, how about buying one fan or the other and
seeing if it is enough. Unless you want one contractor to do it all
at the same time.
| |
| trader4@optonline.net 2007-06-26, 8:25 pm |
| On Jun 26, 4:47 pm, "bent" <b...@rogers.com> wrote:
> the air, if effeciently exchanged may be less, but I've been readinghttp://www.homedepot.com/webapp/wcs/stores/servlet/ProductDisplay?id=...
> and the air in there could be 150 it seems, besides I have dark brown
> shingles
>
It can be 150 with poor attic ventilation and no whole house fan.
But it isn't going to be 150 with any reasonable amount of attic
venting and a whole house fan pushing a huge volume of air in there.
With lots of soffit venting that you have, plus 2 peak vents, there is
quite a bit of area for the whole house fan to push air out of.
And when do u expect to use the whole house fan? It's of most use
when you have cool outside air, like days when it cools off quickly at
night. In many climates, there aren't that many days that make it
practical. For example, it does nothing about humidity, which further
limits it's use. And on days when the attic might be 150, it's going
to be 90 outside and most people would have AC on.
Bottom line, in cases where the attic could reach 150, the solution is
more attic venting, with or without a whole house fan. And I think
the best way to do that is with a ridge vent.
| |
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| |
| Gary KW4Z 2007-06-29, 3:25 am |
| On 6/26/07 2:06 PM, in article 1182881238_30973@sp6iad.superfeed.net, "bent"
<bent@rogers.com> wrote:
> I am going to install a whole house fan to exhaust hot air out of the rooms
> on the top floor , and while I'm at it I'm thinking of installing fan(s),
> most likely one (1). in the roof itself to exhaust the air right out from
> over the ceiling of those rooms. Get it out of the rooms, into that upper
> area; then why not right out of that area, a hot box.
>
> I have looked into the packaging of one of these fans at HomeDepot. Its
> just a 15"! (x6"?) circular shroud, and it is to be mounted anywhere- theres
> no flush mounting or anything, just some metal clips. The pic in the manual
> shows it mounted so it is blowing Horizontally - out of a louver vent
> mounted on the front of an "attic" - above the ceiling & below the roof, at
> the front of the pictured house.
>
> I am thinking I would want to mount a fan under the existing vents on the
> roof, pointing up and out these vents. I do not want to screw around with
> the shingles outside. I've got 2 of the std. size approx 12"x12" vents,
> with screen inside. These vents are only about 7' apart, on adjacent parts
> of the roof, at the rear. The foof is about 10' x 20'. I am thinking of
> wiring a switch inside, beside the whole house fan switch (maybe pull
> cord?), and using metallic shielded cable.
>
> Can I use this type of fan, mount it just below the vent(s) facing up?
> Will I need to worry about a seal to the vent to create a push vacuum?
> Do I need to worry about the size(s)/cfm carefully of the fan(s) wrt the
> whole house fan?
> Theres soffit venting 360, and 2 vents, need I cover (and seal) both (2)
> vents with fans?
>
> http://www.homedepot.com/webapp/wcs...ay?storeId=1005
> 1&langId=-1&catalogId=10053&productId=100055092
> the "interior roof" fan
>
> http://www.homedepot.com/webapp/wcs...ay?id=100018252
> &jspStoreDir=hdus&catalogId=10053&marketID=401&productId=100018252&locStoreNum
> =8125&langId=-1&linktype=product&storeId=10051&ddkey=THDSiteMap
> the whole house fan
>
>
>
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> News==----
> http://www.droptable.com The #1 Newsgroup Service in the World! 120,000+
> Newsgroups
> ----= East and West-Coast Server Farms - Total Privacy via Encryption =----
A couple of web sites for your whole house fan consideration to check
before you decide:
1) http://lib.store.yahoo.net/lib/rewi...sumeralert.html
2) http://www.rewci.com/wholehousefans.html
3) http://www.eere.energy.gov/building.../pdfs/26291.pdf
4) http://www.quietcoolfan.com/faq.html ( nice system, expensive though )
5)http://www.hvacquick.com/wholehouse...le&utm_medium=c
pc&utm_term=whfans&utm_campaign=whf Great looking system.
Don't forget the benefits of Attic Insulation combined. Especially using a
thermal barrier just under your roof decking.
| |
| John Grabowski 2007-06-29, 9:25 am |
|
"Chieh Cheng" <chiehcheng@gmail.com> wrote in message
news:1182895370.013009.290880@o11g2000prd.googlegroups.com...
> On Jun 26, 2:59 pm, Chieh Cheng <chiehch...@gmail.com> wrote:
Its[color=darkred]
theres[color=darkred]
manual[color=darkred]
roof, at[color=darkred]
write-up:http://www.gearhack.com/Forums/Disp...ile=Home/Coolin
g_...[color=darkred]
>
> Oh, one more thing. I forgot to mention that if you are going to put
> in a whole house fan, then you probably don't need powered fans in the
> attic. The whole house fan will create positive pressure in the attic,
> forcing air out the vents. It would create negative pressure in the
> living space to draw air in. You just want to make sure to keep all of
> these passages open when you turn your whole house fan on.
>
> Chieh
>
I read your forum about the fans that you installed in your attic. Those
fans appear to be portable household fans. You didn't give any specifics as
to how you installed them, however I suspect that they are not approved for
the purpose that you are using them for. You should have used gable fans
that were designed and are approved for removing air through the attic
vents. I hope that you didn't use extension cords to wire these units.
| |
| Chieh Cheng 2007-06-29, 5:25 pm |
| On Jun 29, 3:12 am, "John Grabowski" <jgrabo...@optonline.net> wrote:
> "Chieh Cheng" <chiehch...@gmail.com> wrote in message
>
> news:1182895370.013009.290880@o11g2000prd.googlegroups.com...
>
> Its
> theres
> manual
> roof, at
>
>
> write-up:http://www.gearhack.com/Forums/Disp...ile=Home/Coolin
> g_...
>
>
>
>
>
> I read your forum about the fans that you installed in your attic. Those
> fans appear to be portable household fans. You didn't give any specifics as
> to how you installed them, however I suspect that they are not approved for
> the purpose that you are using them for. You should have used gable fans
> that were designed and are approved for removing air through the attic
> vents. I hope that you didn't use extension cords to wire these units.
Thanks. I read your post and responded to it.
Chieh
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