Box Fan to cool Attic

[Senin]

I just saw this video

http://www.youtube.com/watch?v=rhz78ukb0TY

regarding how to keep you house cooler in the summertime by cooling the attic with a box fan.

I was wondering what you guys think of it?

Do you think it would work?

Do you think there is a fire danger with the heat/electricity in the attic?

[Ed Pawlowski]

On Thu, 25 Jul 2013 01:58:34 -0700 (PDT), Senin <se...@inbox.com>
wrote:

Anything that moves the hot air out of the attic space is going to
help. This is just a cheap version of a Whole House Fan.

Whole house fans are better made, more durable, probably safer than a
$15 box fan. It will also move more air.

Good side
On a cool night it will suck in the cooler outside air and vent the
attic

Bad side
One hot day, you are sucking hot air through the house and while it
may cool the attic, it may heat the living space more than keeping
windows closed and shades drawn.

It does not reduce the humidity like an air conditioner.

Another option. Consider an attic fan that just vents the attic and
does not suck the outside air through the house. That is the best
idea when the sun is beating on the room. Use a fan built for those
uses and keep your family safer.

[DerbyDad03]

What kind of attic fan just vents the attic and doesn't suck outside air
into the house?

Isn't that suction dependent on a number of factors, including, but not
limited to, the size of the fan, the ventilation openings in the attic, the
tightness of the house/attic junction and the tightness of the house
itself?

It's not like you can go buy a fan that lists "doesn't suck outside air
into the house" on the spec sheet.

[Nate Nagel]

What are we talking about here? I've seen two different arrangements,
both which work but in different ways.

There's the "whole house fan" typically installed in a hallway ceiling
that will suck air from within the living space and blow it into the
attic; this not only cools the attic but draws (presumably cooler, when
used at night) outside air into the living space.

There are also powered vent type arrangements that only move air through
the attic to keep temps down in there in the summertime; those are
typically controlled by thermostatic switches.

nate

--
replace "roosters" with "cox" to reply.
http://members.cox.net/njnagel

[tra...@optonline.net]

He means a regular attic fan that moves air from outside through the
attic and not through the house living space like the whole house fan
being discussed.

Like Ed said, the guy has just discovered the whole house fan.
But he has some key concepts wrong. He claimed that hot air exits
the attic via the soffits. There should be vents at the top of the
attic, eg ridge vents, gable vents, etc where hot air exits. Cooler
outside air should be coming in from the soffits. If you put in a
powerful enough fan, you could reverse the soffit vent flow, but doubt
a small box fan is going to do that.

He also says that his attic has poor insulation. Well, if that's the
case, then that is costing at least comfort in the summer, assuming there
is no AC and for sure $$ in the winter. So, why not fix that?

The main benefit from a whole house fan is not cooling the attic.
It's about drawing outside air into and throughout the whole house.
That works well if the air outside is cooler and dry. It' isn't very
effective when it's 90F and humid outside. Or even at night when it's
humid outside. I've thought about how much I could use one here in NJ
and the answer is not all that much. Mostly some days in the spring and
fall.

Also, while his concept would do something, a real whole house fan
moves a lot more air, so it would be a lot more effective in moving
air through the whole house. And obviously, all of the above is
incompatible with having the house cooled with AC.

[willshak]

I have a whole house fan. I also have central AC.
In the Summer, the two are not compatible for cooling. You don't want to
pull the cooler air out of the house.
The only times I use the whole house fan is if I have to go into the hot
attic and will be spending some time in there, or to remove smells or
smoke from the house at any time of the year.
Late one night, after letting the dog out to do his business, he got
sprayed by a skunk. A bath with tomato sauce got him cleaned up, but the
skunk smell was throughout the house. The whole house fan was on all
night with all windows open.

--
Bill
In Hamptonburgh, NY
In the original Orange County. Est. 1683
To email, remove the double zeros after @

[DerbyDad03]

"tra...@optonline.net" <tra...@optonline.net> Wrote in message:
...snip

>
> He means a regular attic fan that moves air from outside through the
> attic and not through the house living space like the whole house fan
> being discussed.

Yeah...I knew what he meant but to some extent I disagree with the
words related to "venting just the attic without drawing air
through the house".

I know you know all of this, but there is no fan that will
specifically vent just the attic. It will be dependent on a
number of factors such as intake vents (soffits, gable, etc) fan
power, tightness of attic/house junction, etc.

If there isn't enough intake openings in the attic itself, the fan
is going to pull air from wherever it can. If the house isn't
tight enough, it's going to pull air from the outside.


To simply say "Consider an attic fan that just vents the attic and
does not suck the outside air through the house" can be
misleading especially to someone unfamiliar to the whole concept
of attic ventilation.

----Android NewsGroup Reader----
http://www.piaohong.tk/newsgroup

[Ed Pawlowski]

On Thu, 25 Jul 2013 12:10:50 +0000 (UTC), DerbyDad03
<teama...@eznet.net> wrote:



>
>It's not like you can go buy a fan that lists "doesn't suck outside air
>into the house" on the spec sheet.

Sure you can. Any fan, in fact, can be made to do that. All you need
is a gable vent at each end of the attic. Air comes in one end, goes
out the other. No air enters the living space. Cools the attic.

[Ed Pawlowski]

On Thu, 25 Jul 2013 10:49:25 -0400 (EDT), DerbyDad03
<teamarr...@eznet.net> wrote:



>
>Yeah...I knew what he meant but to some extent I disagree with the
> words related to "venting just the attic without drawing air
> through the house".
>
>I know you know all of this, but there is no fan that will
> specifically vent just the attic. It will be dependent on a
> number of factors such as intake vents (soffits, gable, etc) fan
> power, tightness of attic/house junction, etc.
>
>If there isn't enough intake openings in the attic itself, the fan
> is going to pull air from wherever it can. If the house isn't
> tight enough, it's going to pull air from the outside.
>
>
>To simply say "Consider an attic fan that just vents the attic and
> does not suck the outside air through the house" can be
> misleading especially to someone unfamiliar to the whole concept
> of attic ventilation.
>
>----Android NewsGroup Reader----
>http://www.piaohong.tk/newsgroup

At 5:45 this morning I gave a basic and correct answer. At 8 AM you
can do the engineering, do a layout, and write the installation
instructions, pick nits.

[tra...@optonline.net]

Now I have to disagree. DD has a point. Even with a gable vent in
each end of the attic, you can't guarantee that no air is going to
come from the conditioned space of the house. I'm assuming you mean
that you put the fan in one gable and use the other to supply the incoming
air. That fan lowers the pressure in the attic. The air will then
come into the attic from any and all available routes. Most of it
will likely be from the other gable vent. But some can be from leaks from the conditioned living space, eg around
recessed ceiling lights, around switch plates, bathroom fan openings,
etc. That is one of the big arguments against power venting an attic.
And the effect depends on the CFM of the fan, the available intake openings,
etc.

[Vic Smith]

On Thu, 25 Jul 2013 01:58:34 -0700 (PDT), Senin <se...@inbox.com>
wrote:

Sure, it'll help ventilate and cool that house. Real bargain basement
way to do it, but it's a lot better than nothing.

I don't think much of it because I have A/C to cool my living space,
and the attic is cooled by a powered roof ventilator pulling outside
air in from soffit vents and exhausting it out the roof.
Attic is insulated too.
So they're separately ventilated spaces.

But if I had his situation and wanted to spend the least money
possible, I'd do something similar.
When I lived in house with no A/C I used box fans a lot to direct
outside air in the house.
One in the living room window, and one in the kitchen window, both
blowing air out. Then we'd get a "cool" breeze coming in the bedroom
window, and sleep pretty well on hot nights - with no fan noise.
That house was flat roof, no attic.

That guy basically put in what's usually called a "whole house" fan,
on the cheap. It nothing but win-win for him really.
All it has to do is knock a couple degrees off the living space and
attic temperatures. And it probably does.

As far as "fire danger" if he uses good cords there shouldn't be any.
That box fan uses very little current.

[Red Green]

"tra...@optonline.net" <tra...@optonline.net> wrote in
news:3d67eae6-005c-44b9...@googlegroups.com:

Yes, some measure will enter from the conditioned living space. How much?
Well, the path of least resistance like water and electricity. If the
venting of the attic sucks like having one gable vent, undersize soffit
venting, blocked soffit venting and the like, the attic fan is gonna suck
more conditiond air from the house as it becomes a lesser path of
resistance.

And keep in mind someone decides to put an attic fan in a gable vent and
has ridge venting, path of least resistance ===> in the ridge vent and
out the gable fan.

[Bob F]

I've used a gable vent fan similarly for years.
https://www.acwholesalers.com/Broan/35316-1600-CFM-Gable-Mounted-Powered-Attic-Ventilators/31288.ac?gclid=CJjv3arIzbgCFSU6QgodkF8Afw

I slid some soft pipe insulation over the mounting arms of the fan. These padded
arms rest on the 4 sides of the attic access hole, and pad it to isolate
vibrations from getting through to the house structure. The fan is plugged in in
the attic using an X10 appliance module so I can turn it on/off from several
places in the house using an X10 controller.

I typically run it when the outside temp is lower than inside, then turn it off
and close windows when the outside temp gets higher. The house will usually stay
several degrees cooler than outside at the peak temp of the day.

Cooling the attic is not a big part of this. It is well insulated, so it doesn't
heat the house that much, and I usually don't run the fan during the hot part of
the day.

If your attic is not well insulated, adding a significant layer of fiberglass
batts is a pretty simple thing that will drastically reduce heat in the house.

[Tom]

Hi. I am looking to vent a computer room up into the attic. The exhausted computer room air will be hot, not cool (but not really any hotter than the air that is already in the attic). The attic space is 60' x 40' with soffits on all 4 sides. There is also a long ridge vent on the roof. I will need to pump about 6000 cfm continuously, 24/7/365. I am trying to make sure that this amount of air, and resulting positive air pressure in the attic, won't cause some unforseen problems, and that the soffits and ridge vent will have no issues having that 6000cfm pushing through it?? Greatly appreciate you thoughts on this. Thanks.

--
For full context, visit https://www.homeownershub.com/maintenance/box-fan-to-cool-attic-756927-.htm

[micky]

In alt.home.repair, on Mon, 30 May 2022 22:45:03 +0000, Tom

<ce0537a20a14ccd3...@example.com> wrote:

>Hi. I am looking to vent a computer room up into the attic. The exhausted computer room air will be hot, not cool (but not really any hotter than the air that is already in the attic). The attic space is 60' x 40' with soffits on all 4 sides. There is also a long ridge vent on the roof. I will need to pump about 6000 cfm continuously, 24/7/365. I am trying to make sure that this amount of air, and resulting positive air pressure in the attic, won't cause some unforseen problems, and that the soffits and ridge vent will have no issues having that 6000cfm pushing through it?? Greatly appreciate you thoughts on this. Thanks.

My attic is not finished but I use a roof fan to cool it when the
thermostat says to. After a few years, the soffit screens in the back
of the house were covered by a layer fuzzy seeds, what I called
milkweed, I guess because they were white, but was something else. I
peeled it off, and I think the tree that did it fell down not long
after. I hope so because my friend with the ladder doesn't have the
ladder anymore and I"m too old to go up there again.

[Dean Hoffman]

Why not install an actual attic fan to pull the air out? Maybe variable speed to keep the pressure in the attic within a given range? Add an alarm to let you know if things get of whack.

[trader_4]

Look into whole house fans. That's essentially what you're doing, except just for one
room. And where is the make up air coming from? With a whole house fan, you use
it when it's cool outside and it draws air in from open windows throughout the house.
Are you going to have an open window in the computer room? Humidity? For those
kinds of reasons, computer rooms have AC if needed.