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Old 05-25-2011, 09:27 AM   #16
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Attic venting questions


Hey Grumpy -

I ran across this and thought you might be interested:

Angela of Houston, TX writes...
"I have heard good things about Attic Breeze from one of my neighbors that has installed your solar attic fans. I would like to install a solar attic fan on my home as well, but my roof has ridge vents and I am concerned that these may not work well with the fan. Can your solar attic fans be installed on a home that has ridge vents?"

Yes, you may install our products with an existing ridge vent. However please note that while the solar attic fan is operating, the ridge vent will work in reverse acting as air intake vent. In fact, every passive vent on your roof will act as an air intake vent while the fan is operating. This is not a problem, it is simply a different method of operation for your roof's ventilation system.

Ridge vents operate on the principle of natural draft air convection. This means that as the attic heats up, hot air will rise to the attic ridge and naturally flow out from the ridge vent. For ridge vents to work properly, the attic temperature must be in the range of 130-140F. During normal operation, ridge vents typically produce 3-4 attic air exchanges per hour, not enough to adequately cool the attic and minimize heat transfer into your home.

Attic Breeze solar attic fans operate on the principle of forced draft air convection. Our fans create an air draft through the attic many times more powerful than that of natural draft air convection or wind powered turbine vents. Attic Breeze solar attic fans work the hardest when you need them the most creating a self-regulating ventilation system; the more solar radiation (sunlight) your roof receives, the faster our solar attic fans operate to remove heat. During normal operation, Attic Breeze solar attic fans have the capability of exchanging hot attic air 10-20 times per hour, typically keeping your attic temperature between 5-15F of ambient outside temperature.

When installing our products in conjunction with ridge vents, the solar attic fan unit should be installed a minimum of 5-6 feet away from the ridge vent to allow for balanced air flow through the attic. Experience shows that this distance will typically allow enough space for proper balancing of air intake ventilation from both the ridge vent and other roof vents. When the solar attic fan is not operational, the ridge vent will function as normal.

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Old 05-25-2011, 10:02 AM   #17
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Attic venting questions


I notice that on my old house. It comes on and runs all day.

One thing I don't understand about the solar units is that they will claim a 25W unit and something like 800-1000 CFM. Then a wired unit that consumes 200-300W is about the same or not much more. Are the solar units playing some trickery with the numbers?
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Old 05-25-2011, 10:05 AM   #18
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I have thought about removing the ridge vents that are near the two existing fans and let the fans do the work. (they are less than the 5-6 feet away) but then keeping the ones on the other sections of the house that are over small sections with no much attic area (where the insulation baffles have to be used because the ceiling is so close to the rafters). One example is the long red line I drew in the picture.
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Old 05-25-2011, 07:30 PM   #19
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I haven't looked at the wattages on the Airvent Solarcool fan, but they rate at 880. I have never seen another solar fan rated higher than 880, but I haven't much looked either. Gaf is rated at 550 for their solar fan. Up until about last year these were just about the only players on the market in my area.

I can tell you from experience that the solar fan moves noticeably slower than a wired fan. I really have no way of measuring if the fan rated at 880 is really 880 other than trusting the literature is correct and assume it's been on the market long enough someone would have busted them by now.

I'm not going to argue any more about intake or exhaust or short circuiting. I have stated my reasons for not doing it. I stand by my decisions.
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Old 05-25-2011, 11:54 PM   #20
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Quote:
Originally Posted by Grumpy View Post
The solar fans will still allow air to ventilatewhen the sun goes down. Though they would then become passive instead of active, very much like a large mushroom/breather vent.
But in that situation, would they have sufficient NFA? It seems unlikely to me. And because there would be fewer vents, wouldn't that result in uneven ventilation (though maybe it wouldn't be significant)? It does stay quite warm in the attic after a 100+ day, and I'd want to be sure that heat would have enough ventilation.

Just trying to think this all the way through and look at as many factors as possible - thanks for all the info so far!
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Old 05-26-2011, 08:10 AM   #21
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Quote:
I don't know what dis-information you got from proclaimed experts. I have been a roofer for 13 year and have really been studying attic ventilation for the past 10.
Are you saying you are giving dis-information, or are not an expert?

There are seminars where you can learn to earn a billion dollars in real estate with no money down...if you buy their product.

Think about this, if you direct a vacuum hose towards a pile of dust, what happens?
Unless that ridge vent is directly in front of the power fan, it's not the path of least resistance.


In the absence of any evidence ( real evidence, not a line from a brochure) to the contrary, I'd go with the information presented here; http://www.roofingcontractorreview.c...ntilation.html
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Old 05-26-2011, 11:42 AM   #22
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That's great, you can do it your way and i will do it my way, the way the manufacturers instruct. If nothing goes wrong for you, awesome. If anyone goes wrong for me I am covered by the fact that I did my job to the best of my ability and didn't reinvent the wheel or claim to know more than the inventors of the products I am installing. When something goes wrong and you installed the fan/material against manufacturer specs, guess what: YOU ARE LIABLE. This is true of all products, not just fans. So, please have a

I'm guessing you are Dennis I have conversed with you for years on the various forums as a matter of fact. I can put up a website exactly like this one but claiming the opposite, but to what gain? Your comment about the brochure holds true in this regards as well. Just because YOU built a website with an opposite opinion of mine doesn't make your OPINION any more valid than mine. As for the videos, if I see those studies performed on real properly constructed full size houses, my opinions may be swayed. However on cardboard tests houses, it seems more like arts and crafts and practice making a video than any sort of scientific study. I said that a yer or two ago when you first posted the videos at CT or NRG, I forget which.

Though even if my opinions are swayed, for liability reasons, I will still always install the productsin the means that the manufacturers of the products say.

So again Please have a day and go play with some construction paper and elmers school glue some more. Don't ever come trolling infering that I am some kind of hack giving dis-information. I won't stand for that. On every job I do, I always try to do the job to the best of my ability. I am not always right, nobody is, but I always try. For someone to claim the opposite, well that's just real EZ to do on the Internet, isn't it?
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Sometimes the savings that comes from doing it yourself can be blown away with one mistake.

The information found in this post is not to be considered legal advice. All information should be considered relative, not specific. Never attempt any repairs you are not comfortable with. Always maintain safety! The author of this post takes no responsibility for any losses that occur. Use at your own risk.

Last edited by Gary in WA; 05-27-2011 at 09:57 PM. Reason: Breaking "treat others with respect" rule.
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Old 05-26-2011, 11:53 AM   #23
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Attic venting questions


Quote:
Originally Posted by texasprd View Post
But in that situation, would they have sufficient NFA? It seems unlikely to me. And because there would be fewer vents, wouldn't that result in uneven ventilation (though maybe it wouldn't be significant)? It does stay quite warm in the attic after a 100+ day, and I'd want to be sure that heat would have enough ventilation.

Just trying to think this all the way through and look at as many factors as possible - thanks for all the info so far!
As stated I have seen hybrid solar electric fans. Maybe one fan is not enough, there are calculations you can make which will determine how many vents, fans, etc... you will need.

Then again if you have a wired attic fan without a humidistat also installed, you have the same concerns in winter time about the minimal NFA. You're not just trying to vent heat from the attic, but also moisture which is as much of a problem in winter as it is in summer. There are pros and cons to everything.
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The information found in this post is not to be considered legal advice. All information should be considered relative, not specific. Never attempt any repairs you are not comfortable with. Always maintain safety! The author of this post takes no responsibility for any losses that occur. Use at your own risk.
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Old 05-26-2011, 11:54 AM   #24
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Attic venting questions


If you were installing an Attic Breeze solar attic fan would you follow that manufacturers' recommendation that is ok to have one of their attic fans with a ridge vent?
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Old 05-26-2011, 12:24 PM   #25
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Attic venting questions


Pass the popcorn............
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Old 05-26-2011, 12:29 PM   #26
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I really didn't mean that to be disrespectful to Grumpy. I genuinely respect his opinion and I am just asking what he would do in that case. I know less about this than anyone that has posted in this thread and the only way to learn is to ask questions.
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Old 05-26-2011, 05:08 PM   #27
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I considered a solar powered attic fan until I found out that I would need to install more than 2 in order for it to be adequately sized for my attic (not just an additional cost, but an additional penetration through the roof).

Couple that with the fact that these fans shut off after sunset, I decided to go with an AC powered power vent with an on/off switch in the living space. My power vent has both a thermostat and a humidistat, but I have shut the humidistat feature off.

I have noticed that the 2nd floor is not as hot compared to pre-power vent. Also, I have about a R-55 of insulation in the attic.

It is deathly hot in the attic during the warm months. I've felt sweat come out of the pores of my hands when I was up in there in the past. The rafters were even hot to the touch.

If you insist on installing a power vent, but are concerned about "short circuiting," you could always have the ridge vent closed. The only issue is that during the winter, if you live in a cold climate area, you would be relying on the power vent hole (without the fan turned on) for hot air to escape.

Also, if you close off that ridge vent and your power vent dies, then the heat will also only be able to escape though that penetration.
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Old 05-26-2011, 08:15 PM   #28
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Grumpy.

Quote:
That's great, you can do it your way and i will do it my way, the way the manufacturers instruct. If nothing goes wrong for you, awesome. If anyone goes wrong for me I am covered by the fact that I did my job to the best of my ability and didn't reinvent the wheel or claim to know more than the inventors of the products I am installing. When something goes wrong and you installed the fan/material against manufacturer specs, guess what: YOU ARE LIABLE. This is true of all products, not just fans.
I've also been known to stand on the top step of a step ladder.

Quote:
So, please have a day.
Sorry, I don't do acronyms or text. What does that mean?

Quote:
I'm guessing you are Dennis I have conversed with you for years on the various forums as a matter of fact. I can put up a website exactly like this one but claiming the opposite, but to what gain? Your comment about the brochure holds true in this regards as well. Just because YOU built a website with an opposite opinion of mine doesn't make your OPINION any more valid than mine. As for the videos, if I see those studies performed on real properly constructed full size houses, my opinions may be swayed. However on cardboard tests houses, it seems more like arts and crafts and practice making a video than any sort of scientific study. I said that a yer or two ago when you first posted the videos at CT or NRG, I forget which.
You could build a website and claim the opposite, but you would have nothing to back it up.
You have heard of scale models and wind tunnels, yes?
If you look through the website, you would also see videos of tests done inside real attics. Have you ever tested your vents once installed?

Quote:
So again Please have a day and go play with some construction paper and elmers school glue some more. Don't ever come trolling infering that I am some kind of hack giving dis-information. I won't stand for that. On every job I do, I always try to do the job to the best of my ability. I am not always right, nobody is, but I always try. For someone to claim the opposite, well that's just real EZ to do on the Internet, isn't it?
Your quote from your first post;
Quote:
I don't know what dis-information you got from proclaimed experts. I have been a roofer for 13 year and have really been studying attic ventilation for the past 10.
So
A. You are calling me a hack.
B. You are calling us both hacks.
C. You are an "expert" who knows more than a "proclaimed (?) expert".

Which is it?


So please, have a "righteous indignation" kind of day.

Last edited by Gary in WA; 05-27-2011 at 10:01 PM. Reason: Removed text as per rules.
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Old 05-26-2011, 10:52 PM   #29
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Never once did I claim to be an "expert". Read my postings about attic ventilation and show me once where I said "I am an attic ventilation expert." What I did say: I said I have attended seminars. I have said I have studied ventilation for 10 years. I said I have completed various certifications. I also said I am not an engineer. I also said I didn't design or develope the specifications.

The information I have comes from the manufacturers of the products I installed. That's what's "backing me up". You may gamble with the houses of your customers on some quest to prove "the man" wrong, but I prefer to leave my gambling for the casino not the homes of my customers.

Have I tested some of the ventilation systems I have installed? Yes over the last several years I have had the opportunity on occasion to test some. In most cases there has been no need because <gasp> I did it right the first time.
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Sometimes the savings that comes from doing it yourself can be blown away with one mistake.

The information found in this post is not to be considered legal advice. All information should be considered relative, not specific. Never attempt any repairs you are not comfortable with. Always maintain safety! The author of this post takes no responsibility for any losses that occur. Use at your own risk.

Last edited by Gary in WA; 05-27-2011 at 10:02 PM. Reason: As per rules.
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Old 05-27-2011, 01:13 AM   #30
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Attic venting questions


Grumpy if I may ask then- what about for the new types of roofing where they close off the soffits and ridge vents, spray foam the deck, and condition the attic space instead. then no ventilation is required, correct?

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