DIY Chatroom Home Improvement Forum

DIY Chatroom Home Improvement Forum (http://www.diychatroom.com/)
-   HVAC (http://www.diychatroom.com/f17/)
-   -   solar attic fan mounting in finished attic (http://www.diychatroom.com/f17/solar-attic-fan-mounting-finished-attic-186894/)

johndd34 09-12-2013 11:47 AM

solar attic fan mounting in finished attic
 
Hi
I have a solar attic fan that I will be mounting on my roof. I was wondering if I should mount it on the top of the dormer on the second floor. I have a 1 story house with an A frame roof. The attic is finished and the rooms are fully insulated with baffling between the roof and ceiling insulation. The eaves are open and I have soffit around the whole house. I had an existing chimney that was removed so basically have an accessible hole in tne roof on the dormer. Any advice is appreciated. And no, I am not putting a ridge vent in as they do not work, I've had a home with one before.

RoyalAcresRod 09-12-2013 01:38 PM

I wish you well with your solar attic fan. The research I did showed many units that failed fairly early, problems with control boards, and in many instances an approximate 20-year payback period. As they say...your mileage may vary. Perhaps your electric rates are high enough that your payback period would be more reasonable..

With adequate soffit ventilation, ridge vents DO work well. Cooler air in at the bottom, hot air out the top.

johndd34 09-12-2013 01:50 PM

The problem with ridge vent a is that they create a heat barrier where air is supposed to move Out of the ridge vent....the solar fan also runs on house power in the evening...not worried about warranty as we bought from Costco with amex card which gives us a whole extra year on the warranty and the solar panel has a 20 year warranty

johndd34 09-12-2013 08:34 PM

The problem with ridge vent a is that they create a heat barrier where air is supposed to move Out of the ridge vent....the solar fan also runs on house power in the evening...not worried about warranty as we bought from Costco with amex card which gives us a whole extra year on the warranty and the solar panel has a 20 year warranty

joecaption 09-12-2013 08:56 PM

"The problem with ridge vent a is that they create a heat barrier where air is supposed to move Out of the ridge"

Well that just makes no since.

How does a vent form a heat barrier? It's simply not true.
I agree, big mistake on the solar vent.

johndd34 09-13-2013 09:01 AM

A ridge vent uses thermal conduction to move air out of the attic. Cold air sinks and warm air rises. As the air tries to move out of the vent it must move up then down out of the vent as it is an inverted V. Unless there is a breeze to move the air out effectively the vent really does not do much. In the winter it is practically useless, and if snow gets on the vent it may make it completely inoperative. But anyway, I am still going with the solar vent, I simply wanted input on the mounting location as I already have the item, I did not want an opinion on what else I should have done.:huh:

shazapple 09-13-2013 09:58 AM

Ridge vents work fine... if you install them correctly. Don't buy the cheap rolled mesh type ridge vents as they just get squished. Install the solid plastic baffle type.

I tell everyone this: An attic fan (however it is powered) is a waste of time and money.

veesubotee 09-13-2013 12:45 PM

Quote:

Originally Posted by shazapple (Post 1241307)
Ridge vents work fine... if you install them correctly. Don't buy the cheap rolled mesh type ridge vents as they just get squished. Install the solid plastic baffle type.

My house has full-length soffit vents front and back (perforated panels). My original ridge vent was perforated metal. When roof was replaced, they used Cobra vent.

Using tell-tales, I was never ever to verify airflow into the soffits or out of the ridge, with either system. The attic stays hot as hell.

V

shazapple 09-13-2013 12:53 PM

Quote:

Originally Posted by veesubotee (Post 1241346)
My house has full-length soffit vents front and back (perforated panels). My original ridge vent was perforated metal. When roof was replaced, they used Cobra vent.

Using tell-tales, I was never ever to verify airflow into the soffits or out of the ridge, with either system. The attic stays hot as hell.

V

They probably attached the ridge vent and shingles with an air nailer, which squashes the cobra vent and cuts off the ventilation. Remove this and replace it with a baffle type, such as GAF Snow Country. Verify that there isn't any insulation blocking your soffits, and that the perforated panels aren't just covering solid plywood (which is the case more often than you think). I don't think there would be much of a noticable airflow, but the attic should only be a few degrees above exterior temps.

RoyalAcresRod 09-13-2013 12:57 PM

John, no disrespect intended, but: I realize that most people don't want to hear negative comments about a product already purchased...but many folks on this site feel an obligation to share information we've gained, if only for others who read these posts.

I've gained so much valuable information from others who take the time to share, and have been helped so many times by others who have no idea that the info they shared went so much further than the original person who asked.

All of us wish you well with your solar fan. It's just that many us have read stories of wildly inaccurate Chinese thermostats, brushed motors that die early, etc. too many times. The demos don't demonstrate how little ventilation one gets with 15-20 watts from the panel...and that's often at solar noon, not at the time of day when your attic is at the hottest.

I've heard good things about some German-made fans sold by Horizon Energy Systems in Phoenix. Also, if/when your fan gives up the ghost, Aura Vent (I think out of Boston) makes sturdy vents that can be mounted on the roof jack.

Again, best of luck with your fan. I hope it works well for you.

digitalplumber 09-15-2013 08:11 PM

On an older home, single story with ridge vents and power vents, I could tell the difference in my home when the power vents were not on.

Long home that had open soffit both front and back and eave openings.

Just my experience

Dave Sal 09-17-2013 10:00 PM

Quote:

Originally Posted by shazapple

I tell everyone this: An attic fan (however it is powered) is a waste of time and money.

I disagree completely. I have a tri-level home and the upper attic, which has a southern exposure, used to get outrageously hot during the summer, as in upwards of 120 degrees on a hot day. After the attic fan installation the attic temps stay, at most, about ten degrees higher than the outside air temps on the hottest days. A couple weeks ago the air temperature in my area was 98 degrees. I checked the attic temp and it was 107 degrees.


All times are GMT -5. The time now is 08:14 AM.


Copyright 2003-2014 Escalate Media LP. All Rights Reserved