Hi,
I've recently bought a 1930's house with a whole house fan that discharges directly into my attic. The attic has gable vents, so plenty of discharge space is available. The attic floor joists are 2x6's and the fiberglass insulation is ancient... it's matted down to about 2" high. I'd like to replace the insulation. It's covered in a heavy layer of dust, probably most of which was deposited over the years by the whole house fan.

Is it ok to replace the fiberglass insulation and just let the dust settle on it over time? I have little interest in spending money to cover the attic floor with plywood or OSB just to keep the fiberglass relatively dust free. Should I worry about this sort of thing?

All comments appreciated.
Regards,
Theodore

On Thu, 20 Mar 2014 17:18:49 -0700 (PDT), wrote:

Hi,
I've recently bought a 1930's house with a whole house fan that discharges directly into my attic. The attic has gable vents, so plenty of discharge space is available. The attic floor joists are 2x6's and the fiberglass insulation is ancient... it's matted down to about 2" high. I'd like to replace the insulation. It's covered in a heavy layer of dust, probably most of which was deposited over the years by the whole house fan.

Is it ok to replace the fiberglass insulation and just let the dust settle on it over time? I have little interest in spending money to cover the attic floor with plywood or OSB just to keep the fiberglass relatively dust free. Should I worry about this sort of thing?

All comments appreciated.
Regards,
Theodore

The insulation you have as lost some R value being compressed. I see
no reason that can't leave it in place a blow 6 inches of blown
cellulose insulation on top of it. IMO

On Thu, 20 Mar 2014 17:18:49 -0700 (PDT), wrote:

Hi,
I've recently bought a 1930's house with a whole house fan that discharges directly into my attic. The attic has gable vents, so plenty of discharge space is available. The attic floor joists are 2x6's and the fiberglass insulation is ancient... it's matted down to about 2" high. I'd like to replace the insulation. It's covered in a heavy layer of dust, probably most of which was deposited over the years by the whole house fan.

Is it ok to replace the fiberglass insulation and just let the dust settle on it over time?

Yes, the more insulation the better, at least 6 inches. Keep the heat
of the attic from entering the house, and vice versa in the winter.

I have little interest in spending money to cover the attic floor with plywood or OSB just to keep the fiberglass relatively dust free. Should I worry about this sort of thing?

If you make an attic floor, will dust settle on that instead?

Despite that, I put 3/8" plywood in much of my attic, which is made with
trusses and I later learned wasn't meant to have a floor at all. 3/8"
because anything thicker was hard to carry upstairs, anything thinner
would break when I stepped on it. I have double layers in the most used
places, and for some of the least used places, I'm lying down anythow,
because the pitched roof is too close to the floor. Because I only
have a small trap door, I cut each sheet in 3rds lengthwise, 16".

Nonetheless, it helps store lightweight things up there, heavier things
if it was meant to hold them as your attic might be.

And it kept me from stepping through the ceiling for the first 28 years.
don't know how to put more than 6" of insulation in when the joists are
6" high.

We had a whole house fan in JHS and HS. House had no AC and probably
didn't have much insulation in attic, I can't remember. But the
problems with the fan we
It did nothing during the daytime to keep the house from getting hot.
When the sun went down, turning the fan on would pull outside air
into the bedrooms etc while pulling the hot inside air out of the
bedrooms to the attic and out the vents if there were enough vents.
But if the air outside was still hot -- and often it was 80 or 90 out
until 11PM -- and the air inside wasn't so hot, that would replace the
not so hot inside air with hot outside air. What good is that. Plus it
would bring in all the dust from outside (something I don't care about
but others do.)

In addition, it's hard to insulate the house from the attic where the
whole house fan is. The shutter vanes aren't enough. I think there is
a way to do it, however.


I'm a big believer in roof fans or gable fans, (which also need adequate
outside vents from the attic) though others tell me if my attic floor
were well-enough insulated I wouldn't need one. maybe they're right,
but given my current level of insulation, I like the fan because it
turns on automatically between 9 and 12 in the morning, depending on how
hot the sun makes the attic, and turns off between 7 and 10 (except a
few days when it is so hot out that sucking in outside air does't cool
off the attic enough and the fan would run all night. But even when
it doesn't do that, it can run 8, 10, 12 hours a day. I don't know how
much that costs. For the most part, it's not running when I'm
sleeping.

I have a manual switch on the second floor to turn it off when the
thermostat would turn it on, and I turn the fan off during early spring
and late fall so that the sun will heat the attic and the attic will
heat the house, another thing people tell me wouldn't happen if I had
enough insulataion. I also put on tan shingles instead of dark brown.
Some people say that should make no difference (I guess that also
depends on their being enough attic floor insulatoin) but it seems to
make a difference to me.


All comments appreciated.
Regards,
Theodore

On Thursday, March 20, 2014 7:18:49 PM UTC-5, wrote:
Hi,

I've recently bought a 1930's house with a whole house fan that discharges directly into my attic. The attic has gable vents, so plenty of discharge space is available. The attic floor joists are 2x6's and the fiberglass insulation is ancient... it's matted down to about 2" high. I'd like to replace the insulation. It's covered in a heavy layer of dust, probably most of which was deposited over the years by the whole house fan.



Is it ok to replace the fiberglass insulation and just let the dust settle on it over time? I have little interest in spending money to cover the attic floor with plywood or OSB just to keep the fiberglass relatively dust free. Should I worry about this sort of thing?



All comments appreciated.

Regards,

Theodore

T...I found heaps of info on this very situation on "This Ole House" on YouTube recently. I believe you will be able to sort it all out when you get more info. There is just too much to tell you in this way, but they go up into the attic and show you the "what" and "why" and I personally felt rather well informed after watching (I looked at several different ones).
For instances, there is some discussion on the age and safety of the older fiberglass...and putting sheet fiberglass (thick) (with a moisture barrier) perpendicular to the joist when one already has blown-in cellulose, etc... But Oren may be right! The simplest way is often the best.
Some pre-airconditioned houses were cleverly built with higher than eight foot ceilings--like ten to twelve feet instead--and windows were heavily draped (think -the velvet of the old West or deep South movies) to keep the heat outside. But...if the inside does not cool down at night when it is extra hot, then you may need to use some fans in the rooms you use often. They make one feel cooler without lowering the actual temperature, use a small amount of energy to run, and the sound can be a really pleasant white noise that will help you sleep peacefully.

On Thu, 20 Mar 2014 22:07:00 -0700 (PDT), designingD
wrote:

But...if the inside does not cool down at night when it is ex=
tra hot, then you may need to use some fans in the rooms you use often. Th=
ey make one feel cooler without lowering the actual temperature, use a smal=
l amount of energy to run, and the sound can be a really pleasant white noi=
se that will help you sleep peacefully.

Well this is so true.

I live alone but the table fan in the kitchen, atop the tv, probably
blows air that would make everyone happy. The table fan in the office,
atop the file cabinet, is aimed at the desk chair. The table fan in the
living room would hit 2 or 3 people because the distance is greater, but
could be set to oscillate. All of these are about 10 inches. I even
have a table fan in the basement, about 6 inches, which is always cool
or almost coo but manages to get sort of hot in the middle of the
summer, and it's pointed at my work bench. Floor fans take up too
much space. Window fans don't do much.

And on the window sill above the bed, I had a 4" fan blowing straight at
me. that burned up so now I have a 3 inch fan that goes on the window
sill or on whatever is to my left in the bed.

The bigger fans have light dimmers or motor speed controllers
controlling their speed, so I can get them slow enough that I can't hear
them. Light dimmers work for 3 out of 4 fans, but if the fan stops
spinning the dimmer is set dangerously slow or you can't use a light
dimmer at all with that fan.

On 3/20/2014 8:59 PM, Oren wrote:
On Thu, 20 Mar 2014 17:18:49 -0700 (PDT), wrote:

Hi,
I've recently bought a 1930's house with a whole house fan that discharges directly into my attic. The attic has gable vents, so plenty of discharge space is available. The attic floor joists are 2x6's and the fiberglass insulation is ancient... it's matted down to about 2" high. I'd like to replace the insulation. It's covered in a heavy layer of dust, probably most of which was deposited over the years by the whole house fan.

Is it ok to replace the fiberglass insulation and just let the dust settle on it over time? I have little interest in spending money to cover the attic floor with plywood or OSB just to keep the fiberglass relatively dust free. Should I worry about this sort of thing?

All comments appreciated.
Regards,
Theodore

The insulation you have as lost some R value being compressed. I see
no reason that can't leave it in place a blow 6 inches of blown
cellulose insulation on top of it. IMO

What kind of cellulose action do you expect
when the OP turns on his whole house fan?

--
..
Christopher A. Young
Learn about Jesus
www.lds.org
..

On Thursday, March 20, 2014 8:18:49 PM UTC-4, wrote:
Hi,

I've recently bought a 1930's house with a whole house fan that discharges directly into my attic. The attic has gable vents, so plenty of discharge space is available. The attic floor joists are 2x6's and the fiberglass insulation is ancient... it's matted down to about 2" high. I'd like to replace the insulation. It's covered in a heavy layer of dust, probably most of which was deposited over the years by the whole house fan.


Is it ok to replace the fiberglass insulation and just let the dust settle on it over time? I have little interest in spending money to cover the attic floor with plywood or OSB just to keep the fiberglass relatively dust free. Should I worry about this sort of thing?



It worked that way for many years, so I guess if you start over
with more fiberglass insulation on top, no reason you can't do
it again. Since it's going over existing insulation, the new
insulation should not have a vapor barrier.

Also, DIK where you live, but in most climates the whole house fan
is only effective and practical for some limited days, eg early
Summer. It doesn't remove humidity and if it's hot outside, it
only draws hot air in. It's most effective if you have cool nights
and can draw in cool dry air. But if it's humid out, it doesn't
work well then either. You may find that you don't use it that
much anyway.

On 3/20/2014 8:18 PM, wrote:
Hi,
I've recently bought a 1930's house with a whole house fan that discharges directly into my attic. The attic has gable vents, so plenty of discharge space is available. The attic floor joists are 2x6's and the fiberglass insulation is ancient... it's matted down to about 2" high. I'd like to replace the insulation. It's covered in a heavy layer of dust, probably most of which was deposited over the years by the whole house fan.

Is it ok to replace the fiberglass insulation and just let the dust settle on it over time? I have little interest in spending money to cover the attic floor with plywood or OSB just to keep the fiberglass relatively dust free. Should I worry about this sort of thing?

All comments appreciated.
Regards,
Theodore

I did this in a house I once owned. It was trussed construction and
there was about 3-4" of blown in fiberglass. I has a removable exhaust
fan mounted in the scuttle hole ... it was designed for that purpose.
Later I decided to add more insulation and had about a foot of cellulose
blown in. But before doing so, I build a 2' wide walkway. Actually, it
was a 2' wide crawl way; the peek was only 4' high right along the crawl
way. First I put 2" thick of foam board down with the final layer of
plywood for walking ... I mean crawling. Knowing the blown in
insulation would be all over the crawl way, I put vertical pieces of
cardboard along each side. Never had a problem with the fan messing
with the cellulose insulation. When 1st done, it was very thick and if
you touched it, you would propagate waves in it. But, that quick
stopped as the air eventually left and it settled to a less thick
coverage. After using the crawl way to store many things, like
Christmas and Halloween decorations, I only wish I had made it 4' wide
instead of 2'. BTW, I was able to get the 2' x 8' pieces of plywood and
foam up there because I had the front of the house opened for a
remodel/fix up. So, I cut a 2' wide hole in the sheathing and slid in
the 8' long panels. And then covered the hole in the sheathing and put
new siding over the entire wall.

On 3/21/2014 7:15 AM, Stormin Mormon wrote:
On 3/20/2014 8:59 PM, Oren wrote:
On Thu, 20 Mar 2014 17:18:49 -0700 (PDT), wrote:

Hi,
I've recently bought a 1930's house with a whole house fan that
discharges directly into my attic. The attic has gable vents, so
plenty of discharge space is available. The attic floor joists are
2x6's and the fiberglass insulation is ancient... it's matted down to
about 2" high. I'd like to replace the insulation. It's covered in
a heavy layer of dust, probably most of which was deposited over the
years by the whole house fan.

Is it ok to replace the fiberglass insulation and just let the dust
settle on it over time? I have little interest in spending money to
cover the attic floor with plywood or OSB just to keep the fiberglass
relatively dust free. Should I worry about this sort of thing?

All comments appreciated.
Regards,
Theodore

The insulation you have as lost some R value being compressed. I see
no reason that can't leave it in place a blow 6 inches of blown
cellulose insulation on top of it. IMO

What kind of cellulose action do you expect
when the OP turns on his whole house fan?


I don't know what Oren expects, but I would expect none. I have that
situation in my house and the blown in insulation does not move when the
fan is turned on.

My thought was similar to yours. So, before I bought the house I went
into the attic, closed the hatch and had them turn the fan on. The
attic pressurized immediately and the insulation didn't move. The
turbulence was all near the peak.

On 3/21/2014 10:04 AM, Mike wrote:
On 3/21/2014 7:15 AM, Stormin Mormon wrote:
What kind of cellulose action do you expect
when the OP turns on his whole house fan?


I don't know what Oren expects, but I would expect none. I have that
situation in my house and the blown in insulation does not move when the
fan is turned on.

My thought was similar to yours. So, before I bought the house I went
into the attic, closed the hatch and had them turn the fan on. The
attic pressurized immediately and the insulation didn't move. The
turbulence was all near the peak.

Reality wins, every time. Thanks for the
field report. I truly didn't know what to
expect. I'd mental visions of a massive
grey snow storm.

--
..
Christopher A. Young
Learn about Jesus
www.lds.org
..

On Fri, 21 Mar 2014 10:40:57 -0400, Stormin Mormon
wrote:

On 3/21/2014 10:04 AM, Mike wrote:
On 3/21/2014 7:15 AM, Stormin Mormon wrote:
What kind of cellulose action do you expect
when the OP turns on his whole house fan?


I don't know what Oren expects, but I would expect none. I have that
situation in my house and the blown in insulation does not move when the
fan is turned on.

My thought was similar to yours. So, before I bought the house I went
into the attic, closed the hatch and had them turn the fan on. The
attic pressurized immediately and the insulation didn't move. The
turbulence was all near the peak.

Reality wins, every time. Thanks for the
field report. I truly didn't know what to
expect. I'd mental visions of a massive
grey snow storm.

I've not seen cellulose flying around. Once blown in, it will settle
and pack down a bit. If I open my attic shuttle with the AC running I
can feel a good draft surging up into the attic. No problem.

Stormin Mormon wrote:
On 3/20/2014 8:59 PM, Oren wrote:
On Thu, 20 Mar 2014 17:18:49 -0700 (PDT), wrote:

Hi,
I've recently bought a 1930's house with a whole house fan that
discharges directly into my attic. The attic has gable vents, so
plenty of discharge space is available. The attic floor joists are
2x6's and the fiberglass insulation is ancient... it's matted down to
about 2" high. I'd like to replace the insulation. It's covered in a
heavy layer of dust, probably most of which was deposited over the
years by the whole house fan.

Is it ok to replace the fiberglass insulation and just let the dust
settle on it over time? I have little interest in spending money to
cover the attic floor with plywood or OSB just to keep the fiberglass
relatively dust free. Should I worry about this sort of thing?

All comments appreciated.
Regards,
Theodore

The insulation you have as lost some R value being compressed. I see
no reason that can't leave it in place a blow 6 inches of blown
cellulose insulation on top of it. IMO

What kind of cellulose action do you expect
when the OP turns on his whole house fan?


I don't have a problem. Cellulose stays put.

Greg

Reading the subject line, look like take all the
insulation out, and put in a fan instead of
insulation.

--
..
Christopher A. Young
Learn about Jesus
www.lds.org
..

I have a whole house fan and use it mostly in the spring and fall when the nights are cool. To use the fan you must have windows open to draw in the cool air. If you are thinking of using it with the AC I am not sure that would work. I have gas heat and hot water and the pilot lights on those units are blown out if the windows are not open for the attic fan. I use circulating room fans to move air around our bedrooms at night. It helps make the room feel cooler.

I also agree insulation and good tight windows will help. You might consider having an energy audit done on your house to see where you may have issues. For more information http://www.epdmcoatings.com/liquid-rubber.html

On Thu, 27 Mar 2014 05:11:14 -0700 (PDT), Albert Mclaren
wrote:

To use the fan you must have windows open to draw in the cool air.

Then you need more vents along your eaves. You should not need to open
windows, or have pilot lights blow out when you use the WWfan. Someone
likely just installed the fan, and never added the venting needed to go
with it. Those fans are mostly just intended to be used when the
temperatures outside are real hot and the sun beating down on the roof
makes the attic real hot. You should be venting the heat out of the
attic, not sucking air out of the living space. Of course if you dont
have an AC, and and cool your house wiht fans only, and keep the windows
open on hot days, then using this fan too cool the entire structure
could work, and is cheaper to run than an AC.

On Thursday, March 27, 2014 1:20:02 PM UTC-4, wrote:
On Thu, 27 Mar 2014 05:11:14 -0700 (PDT), Albert Mclaren

wrote:



To use the fan you must have windows open to draw in the cool air.



Then you need more vents along your eaves. You should not need to open

windows, or have pilot lights blow out when you use the WWfan. Someone

likely just installed the fan, and never added the venting needed to go

with it.

Of course you need to open windows with a whole house fan. That is
exactly how they function. They draw air through open windows, thorough
the house into the attic and out vents in the roof, gables and soffits.



Those fans are mostly just intended to be used when the

temperatures outside are real hot and the sun beating down on the roof

makes the attic real hot. You should be venting the heat out of the

attic, not sucking air out of the living space.

That's what an attic fan does, which is very different from a
whole house fan.


Of course if you dont

have an AC, and and cool your house wiht fans only, and keep the windows

open on hot days, then using this fan too cool the entire structure

could work, and is cheaper to run than an AC.

I think the whole concept of a whole house fan in most cases is dubious.
It's also very climate specific. For example, here in the NJ/NYC area
I don't think you'd get much benefit from it. It would only be useful
in Spring. In summer, it does nothing to deal with humidity. And if
you have AC then I think it makes very little sense. If you have AC
running in the day, you don't need the fan to bring in humid air at
night. And if the air outside is cool enough to make sense bringing
it in, then the AC can do the same thing, ie cool the house off quickly
and take the humidity out too without using a lot of energy.

On 3/27/2014 12:20 PM, wrote:
On Thu, 27 Mar 2014 05:11:14 -0700 (PDT), Albert Mclaren
wrote:

To use the fan you must have windows open to draw in the cool air.

Then you need more vents along your eaves. You should not need to open
windows, or have pilot lights blow out when you use the WWfan. Someone
likely just installed the fan, and never added the venting needed to go
with it. Those fans are mostly just intended to be used when the
temperatures outside are real hot and the sun beating down on the roof
makes the attic real hot. You should be venting the heat out of the
attic, not sucking air out of the living space.

You have confused attic fans with whole-house fans. This thread is
about whole-house fans. They're run when outside temps are cooler than
inside temps, so you open the windows when the fan kicks on and it
pulls out the hotter indoor air while drawing in the cooler outdoor air.

They're generally used in areas where night temperatures are
consistently cooler than day temperatures. Cooling the house at night
with outdoor air saves on the a/c. They're not useful when it's very
hot and sticky outside. They tend to leak warm interior air into the
attic in the winter, which can contribute to ice dams in snowy
climates, and the home occupants can't forget to open windows when the
fan is turned on. So they're not for everyone.

trader_4 wrote: "Of course you need to open windows with a whole house fan. That is exactly how they function. They draw air through open windows, thorough "


Precisely the WRONG advice - at least here in New England where summers are 'triple-H' so to speak. All keeping the windows open would do is cause the fan to suck in all the humidity to replace the hot air it removed.


My thermostatic attic fan has been coming on at attic temp=80F for decades, going back to when my parents owned the place. We open the windows late in the evening, and close them early the following morning. By midday, the house temp is still around 70, and the fan comes on.


Reduces our AC season by one month at either end.

trader_4 wrote: "Of course you need to open windows with a whole house fan. That is exactly how they function. They draw air through open windows, thorough "


Precisely the WRONG advice - at least here in New England where summers are 'triple-H' so to speak. All keeping the windows open would do is cause the fan to suck in all the humidity to replace the hot air it removed.


My thermostatic attic fan has been coming on at attic temp=80F for decades, going back to when my parents owned the place. We open the windows late in the evening, and close them early the following morning. By midday, the house temp is still around 70, and the fan comes on.


Reduces our AC season by one month at either end.

On Friday, March 28, 2014 7:06:18 AM UTC-4, wrote:
trader_4 wrote: "Of course you need to open windows with a whole house fan. That is exactly how they function. They draw air through open windows, thorough "





Precisely the WRONG advice - at least here in New England where summers are 'triple-H' so to speak. All keeping the windows open would do is cause the fan to suck in all the humidity to replace the hot air it removed.



As both Moe and I have tried to explain, you and Caulki are confusing
a "whole house fan" with an "attic fan". The thread is about a whole house
fan *not* an attic fan. They are different and serve different purposes.
No one would be talking about opening windows with an attic fan as
it makes no sense and would have no effect. Do some googling and learn
the difference.







My thermostatic attic fan has been coming on at attic temp=80F for decades, going back to when my parents owned the place. We open the windows late in the evening, and close them early the following morning. By midday, the house temp is still around 70, and the fan comes on.



Sure, but the thread and my comments were about a "whole house fan",
not an attic fan, which is what you have.






Reduces our AC season by one month at either end.

If you think your attic fan is reducing your AC season by one month
at each end, ie by two months in New England, you're nuts. Even if you
had no attic insulation, it wouldn't make that much difference. And
if you have an attic fan, having it come on at 80F is nuts too. You
should have plenty of insulation in the attic. If it can keep the
house well insulated in winter when the temperature difference can
be 70 - 10 = 60 degrees, what's the urgent need to start cooling the
attic when it's only 80F in the attic, ie a temp difference of just
5 or 10F? There really isn't a need for it to come on until it's 100F.

And further, if you look at the best advice from leading building
science folks today, they tend to recommend not having a powered fan
at all. Instead they recommend ridge vents and ample soffit venting.
One factor they consistently point out is that the attic fan creates
a low pressure in the attic, which in turn pulls conditioned air from
the living space. That happens around recessed light fixtures, bath fans,
wall outlets, ie any place air can go. So, you can be pulling the air
you're paying to run AC on into the attic, increasing the AC load. And
if you have it set at 80F, it will be running a whole lot.

I have two attic fans and when the roof is redone, both are being replaced
with ridge vents.

On Fri, 28 Mar 2014 04:06:18 -0700 (PDT),
wrote:

trader_4 wrote: "Of course you need to open windows with a whole house fan. That is exactly how they function. They draw air through open windows, thorough "


Precisely the WRONG advice - at least here in New England where summers are 'triple-H' so to speak. All keeping the windows open would do is cause the fan to suck in all the humidity to replace the hot air it removed.


My thermostatic attic fan has been coming on at attic temp=80F for decades, going back to when my parents owned the place. We open the windows late in the evening, and close them early the following morning. By midday, the house temp is still around 70, and the fan comes on.


Reduces our AC season by one month at either end.

Trader is "precisely" correct. _Whole house fans_ should have a window
open during low humidity periods. This allows hot air in the home to
be evacuated up and through the attic. Usually, whole have fans are
mounted in the hallway ceiling.

An "attic fan" is another story, as pointed out by Trader.