Attic fan question

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Hmmm, You already knew that he knew the answer to his question. Why waste time and bandwidth replying? That's even funnier.
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<stuff snipped>

Absolutely. Think of a car with its windows rolled up tight and how hot it gets v. one with the windows wide open. That huge amount of hot air in your attic needs to be vented, and fan venting (with a pull/push arrangement) will cool things down tremendously.
-- Bobby G.
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On Mon, 28 Jun 2010 11:06:54 -0400, Jan Philips

You're joking, rigiht? Fan fails, temps go way up and you wonder if you should replace the fans?
Only replace them if 120 bothers you.
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wrote:

As I understand it you made the attic into a living space so my advise is forget the attic fans. In fact close off the holes from them and insulate the heck out of the whole attic. Don’t leave any place between the attic and the outside that is not very well insulated, turn on you A/C and enjoy.
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Molly Brown wrote:

Don't think so. The more the attic space can be ventilated, the better. Most homes have ridge vents or whirly-gig thingamajigs. A significant number have attic exhaust fans.
Whichever scheme you use (and you can use more than one - I have both ridge vents and whirling dervishes) remember Axiom I of attic ventilation: You can't have too many soffit vents.
One pundit advised COVERS for the soffit vents to be put in place during hurricanes, much like storm windows, so that giant wind gusts won't blow off the roof. Sounds reasonable. (During Hurricane Yikes, I did have one whirlie gizmo blow off.)
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wrote:

I think you misunderstood.

Speaking of ridge vents mine have had to be cleaned of some fluffy seed material that floats around here in June. Every ten years or so, but it's like a blanket by that time. Maybe earlier would be better.
My neighbor who relies on convection to vent her attic doesnt' seem to have any of this stuff on her vent screening, and afaik, they haven't bee cleaned in 30 years.

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mm wrote:

Sounds like cottonwood trees. When there is a layer of it not close to anything you want to keep, try lighting the stuff. If it hasn't been rained or dewed on it burns as if you spilled a line of gunpowder and lit it. A real bitch for cars with open windows, the stuff gets everywhere, and when you drive off, the stuff swirls around you like you are in a snow globe.
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wrote:

Yeah, I think it's cottonwood.
I'll try setting it afire sometime. There's a bunch lying in my back yard.
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mm wrote:

You have power vents and ridge vents? If the power vent is sucking air into the ridge vents, something is wrong, and the ridge vents are "short-circuiting" the air ventilation. My understanding is that the advantage of ridge vents is that they inprove circulation by exhausting at the highest point of the roof. They probably don't make a lot of sense with power vents. Increasing the soffit vent area could decrease the cotton buildup.
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wrote:

I appreciate the suggestions.
It's the screening on the full-width soffit vents that gets covered in this fluffy stuff. So that means I'm sucking more air, a lot more air, in the soffitt vents than my neighbor is. I also have a full-width ridge vent and yes, I'm surely sucking air in with that when the fan is on, at least near the fan, but that in itself isn't bad if the air in the attic is changed. When the fan is not on, the ridge vent works as designed.
The cottonwood stuff is only on the screen in the back of the house, but there is no cottonwood stuff in the front of the house at all, not by the car like for Tony.
I could have removed the ridge vent when the shingles were replaced, but then if the fan motor broke for a while, there would be very little outlet venting

The eaves themselves could have been made a lot bigger, but given the size of the eaves, I don't think the soffit vents can be bigger. They're the entire width of the house, on the front and back of the house, about 6 inches wide or a little more. The other 3 inches are wood that the screen is stapled to.
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mm wrote:

That sounds like plenty of soffit venting. I'd be tempted to research speed controls for the fan. Slow it down during the cottonwood season.
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wrote:

A good idea. I'll do that. Thanks.    

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Molly Brown wrote:

Whoa! Is that a new theory? I don't think so. Insulation is good but good venting is necessary. Remember heat(hot air) rises. You are looking for condensation or frost w/o vent.
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On Mon, 28 Jun 2010 11:06:54 -0400, Jan Philips

Where I come from, attic fans mean fans between the attic and the floor below. And are only turned on after it gets cooler outside.
Fans in the roof are called somehting I forget that I consider ambiguous. I call them roof fans. I think if that's what you meant that would be far less consufins.
I'm had one for 27 years. Someimes the motor lasts 8 or 10 years, one as little as two. That's the way the first two were and they both came from the fan manufacturer. I haven't tried to oil or repair them. Can they be oiled? Now I buy motors locally at Eledric Motor Repair. The current fan is maybe 8 years old,
Maybe, just maybe if I had more insultatoin in the floor of my attic, I wouldn't benefit from my roof fan, but when the fan is broken, it's much hoter on the second floor, as you can see yourself
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Bob wrote:

Those are "whole house" fans, not attic fans, I believe.

More insulation is a very cheap fix in such a case.
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Fixed, not necessarily replaced. A new motor is one heck of a lot cheaper than a complete new install.
If you do replace the units read your new warranty carefully. A lot of the fan makers will provide a new motor for a failed one for as long as you own the house. And yes, I have collected on that warranty at least twice.
--
Colbyt
Please come visit http://www.househomerepair.com
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With the US governemnt, they appear to love disasters, and people depending on government for welfare. Using that perspective and world view, you should leave your fans broken. You should then go take a fire axe, and chop up your outdoor units. Do not allow anyone to repair them, in violation of the Jones act. Apply for federal aid, and food stamps.
On the other hand. A working American like my self would ask if you're out of your mind to delay, even a day, the repairs. Get with it! Aunt Bee; call the man! (Andy Griffith.)
--
Christopher A. Young
Learn more about Jesus
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wrote:

Fix the fans so that the conditions are the same as when you installed the upstairs AC unit for the former attic space, OR upgrade your AC unit for the affected space to a new one which more accurately reflects the actual cooling load it needs to be able to keep up with without the attic vent fans helping...
Your AC unit can not keep up because it is undersized for the current cooling load it is having to deal with and it was selected to be used WITH the fans working... If you replace both of the attic fans you will find the AC up in the former attic space works better than it has been for the past year...
When you finished your attic into living space how much insulation did you put in the walls/rafter areas ? If you filled the entire rafter compartment with insulation batting your roof becomes a MASSIVE HEAT SINK and will absorb and store large amounts of heat during warm days because the underside of the roof is no longer vented to allow a barrier of moving air to carry the excess heat out -- this is why soffit and ridge vents are installed, to promote a ventilation path on the underside of the roof to allow air to circulate... If you have restricted that airflow too much or closed it off, you will have cooling issues in the living area that used to be attic...
~~ Evan
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