# Attic Ventilation Fan



## joecaption (Nov 30, 2011)

Need to know the big picture.
Roof fans are useless unless you have enough soffit vents, and make sure there not blocked with insulation.
In about 95% of the cases you would be better off with a ridge vent.
It vents the whole roof, no noise, looks a whole lot better.


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## brendelac (Sep 19, 2014)

Installing a ridge vent would be a pretty big job, wouldn't it? The soffits are not blocked, but I did just read that they should not be covered with netting which mine are.


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## gregzoll (Dec 25, 2006)

The motor is dead. Mine only lasted maybe a year and a half. I contacted Lomanco and they sent me a brand new motor.

Turn off power, unhook the thermosta box, the use Alligator clip jumpers between the fan power wires and the wire that goes to the thermostat.


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## ProGreen (Oct 2, 2014)

You okay with the possibility of whole house negative pressure? As an important aside, attics should have ion/smoke detectors too.


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## joecaption (Nov 30, 2011)

Unless it's a 12/12 pitch and more then a one story house installing a ridge vent is a DIY 101 job.
A hammer and a flat bar are the only tools needed.


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## gregzoll (Dec 25, 2006)

ProGreen said:


> You okay with the possibility of whole house negative pressure?


Go back and read about the fan the OP has. It is not a whole house fan. They have a Attic Power Ventilator.



> As an important aside, attics should have ion/smoke detectors too.


Cite the requirement on that. If that was the case. Think about it... They would be going off constantly.


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## gregzoll (Dec 25, 2006)

joecaption said:


> Unless it's a 12/12 pitch and more then a one story house installing a ridge vent is a DIY 101 job.
> A hammer and a flat bar are the only tools needed.


It also requires having the guts to get on the peak of the roof, a safety harness and a cordless saw to cut out the 1" on both sides, to allow the Ridge Vent to vent properly. Also requires knowledge on placing the Ridge Shingles over it. The OP still is required to have Soffit vents to allow the chimney effect to pull air in through the Soffit's and out through the Ridge.


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## gregzoll (Dec 25, 2006)

Brendelac, the Solar powered Attic Ventilator's require Sun all of the time to properly work. As for your attic temp. Because attics always have a really low Relative Humidity, it will feel hotter up there, than it actually is. You really need to get a Temp/Humidity unit that allows for remote senders.

I have one of the older Radio Shack Weather Station units, that allows up to three remote sensors. One sensor is in my attic, the other down in my Basement.

When we had our roof redone, with Roof vents put in, to help allow the attic to vent. Because there were gable vents on the house, that had been there for around 60 years. Our attic would not vent properly, and would get up to 145 deg. F. Put in a Power Ventilator, the attic would get at the highest of 115. Drop down by 6:30 pm around mid nineties where the shut off set point is for the Power ventilator. It would still be around the mid 80's in the Attic even at Midnight.

In May we had our house resided. I had them remove the Gable vents and put in two attic vents down towards the Blown-in Insulation level. We now only see at most, attic temps around 105 max. By 5:30 pm, the temp is already down around the mid 80's. By Midnight, it is around 5 degrees higher than the actual outside air temp. I never hear the Power Ventilator kick on, unless the house is really silent, or I lift the cover for the Attic Scuttle.

In your case, just like all others. You have to go into the attic and make sure any entry points for wiring, plumbing vents, bath exhaust (flex house with insulation jacket, to keep the moisture from condensing), lighting fixtures and/or boxes are sealed with caulk or Fire Stop foam that Big Stuff sells.

Make sure Baffles are at every rafter bay, so that the Soffit vents can properly work. That also means possibly adding more insulation up there, to help keep the conditioned part of the house cool, not pull any heated air from the attic.

If you have the proper Ridge & Soffit vents, proper amount of insulation in the attic, it will make a huge difference inside the home. Along with using Window tint film that Gila manufactures to help stop direct Sunlight from heating up the interior.

If your attic venting is working correct via Chimney effect. You should never need a Attic Power Ventilator.


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## ddawg16 (Aug 15, 2011)

I need to find the link......but it was a good discussion on attic venting.

In the case of powered fans, the jury was deadlocked as to any real benefit. I 'used' to have one....I didn't notice any difference. Part of the problem, if the wind was blowing the wrong direction, the fan was fighting the wind. I think I get better results with the whirly bird type of vent. In a couple of years, I'm going to redo my gables and just remove the gable vents and just depend on the soffit vents.

And....if I have a fire in the attic....I doubt a smoke detector is going to be much good. By that point it's too late.


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## brendelac (Sep 19, 2014)

Thanks for everyone's input. The whirlybird turbines are another option to consider as well. My neighbors have them and they are moving at a decent speed right now even though (according to the trees) there is zero wind. 

Since I already have wiring and the hole in the roof for a powered/passive vent, I think that will be what I go with rather than a ridge vent. It's too bad because I just had my roof re-shingled in 2014 and had I even known about ridge vents, I may have had them install one at the time. I've been reading though that for a ridge vent to be fully effective, it needs a full length soffit vent.

Still undecided about solar, powered or passive. There is a company called maximum ventilation that makes an interesting alternative to the turbine as well 

http://www.ventilation-maximum.com/English/product-model301.html


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## GrayHair (Apr 9, 2015)

ProGreen said:


> You okay with the possibility of whole house negative pressure? As an important aside, attics should have ion/smoke detectors too.


*When is the last time you were in an attic on a sunny July afternoon? * Attic temperatures commonly exceed 130 and the electronics would most likely not survive the first summer. 

Manufacturer's installation instructions will state a temperature range in which the device will operate. Those instructions are part of the NRTL (UL) testing/listing and violating them voids the listing as well as the warranty.


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## ProGreen (Oct 2, 2014)

gregzoll said:


> Go back and read about the fan the OP has. It is not a whole house fan. They have a Attic Power Ventilator.
> 
> Cite the requirement on that. If that was the case. Think about it... They would be going off constantly.


Energy Vanguard Blog
"One reason power attic ventilators don't help
In my original article, I focused on makeup air. That is, I said that when you run a power attic ventilator in a typical house, yes, it will cool the attic down. A significant amount of that cooling is likely to come from conditioned air being sucked up from the house below. Most ceilings aren't air-sealed well, so putting a negative pressure on the attic will do that..."
http://www.energyvanguard.com/blog-...e-1-Reason-Power-Attic-Ventilators-Don-t-Help

You're right Greg: "habitable attics" only. 
R314.3 Location. 
Smoke alarms shall be installed in the following locations: 

1. In each sleeping room.
2. Outside each separate sleeping area in the immediate vicinity of the bedrooms.
3. On each additional story of the dwelling, including basements and habitable attics but not including crawl spaces and uninhabitable attics. In dwellings or dwelling units with split levels and without an intervening door between the adjacent levels, a smoke alarm installed on the upper level shall suffice for the adjacent lower level provided that the lower level is less than one full story below the upper level.

http://publicecodes.cyberregs.com/icod/irc/2012/icod_irc_2012_3_par200.htm


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## brendelac (Sep 19, 2014)

Will a turbine be counter-productive if it is used with other passive exhaust vents? I have two gable vents and two roof vents which are just open exhaust points. Wondering if the turbine might draw air in through either of these openings rather than the soffits?


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## gregzoll (Dec 25, 2006)

GrayHair said:


> *When is the last time you were in an attic on a sunny July afternoon? * Attic temperatures commonly exceed 130 and the electronics would most likely not survive the first summer.
> 
> Manufacturer's installation instructions will state a temperature range in which the device will operate. Those instructions are part of the NRTL (UL) testing/listing and violating them voids the listing as well as the warranty.


The Attic would only get to that temp, if improperly ventilated. Mine gets at the most, around 108-112 on a hot Summer Day.

I have replaced the motor once already on the Lomanco Power vent. The replacement has already burnt up the bearings in the motor. I am pulling it out, and letting the attic natural vent.

The only reason I had a power vent installed. Was because I only had Gable Vents on the North & South side, which did nothing when we had roof vents installed when the Shingles were replaced.

Power Vent fans are just used as a crutch, when you do not have proper chimney effect, to keep air movement in the attic, so that it does not bake the shingles, and cause the living area of the house to get hot, even when there is proper insulation up there.


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## gregzoll (Dec 25, 2006)

Progreen when a person installs a Power ventilator for an attic space. It is used to pull any hot air out of there. Regardless if the holes, etc. are properly sealed or caulk. You will never get negative effects of it pulling air from inside the living space. What it would do, is pull air in from the roof vents, and then exhaust it out of the Power Ventilator. That means any area at least 2' from the roof, will never get properly cooled.


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## Gary in WA (Mar 11, 2009)

http://www.buildingscience.com/documents/insights/bsi-035-we-need-to-do-it-different-this-time

http://www.energyvanguard.com/blog-...c-Suck-Power-Attic-Ventilators-Are-a-Bad-Idea

http://www.homeenergy.org/show/article/year/1995/id/1165

http://www.buildingscience.com/documents/digests/bsd-102-understanding-attic-ventilation

Gary


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## brendelac (Sep 19, 2014)

Thanks for the links, Gary. From what I've been reading, going with a turbine vent or something like I linked to in post 11 will be optimized by blocking off any existing exhaust vents - gables etc. Also, one turbine would not be enough for my attic - 1450 sq. ft. so that probably means an additional hole in the roof.


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## brendelac (Sep 19, 2014)

I decided to address my intake issue before tackling my exhaust issue. I've added 4 more 15x7 vents for 8 total. Now I am wanting to to put in rafter baffles - the existing ones were 11" wide (I have 24" rafters) with no support in the middle of the airflow passages so most of them are pressed flat by the insulation. On top of that, I only have maybe 15 total. If each rafter had a baffle, there should be 40. 

I purchased 40 pieces of durovent, and went up into the attic, but gave up after trying to install the first one. After using a rake to move away the blown insulation, I found that I have batts glued between the ceiling joists. I tried passing the durovent between the batts and roof decking, but it's getting torn on the roofing nails and I can't tell if I have it through far enough because I don't have continuous soffits and therefore can't see light unless I am directly in line with one of my eight soffit vents. 

Doing this 40 times over is going to really suck. I've thought about removing my plywood soffits, installing the baffles from the outside and then replacing with continuous, but my soffts are 22" wide and it seems like standard is now 16".

Is there a better way to retrofit rafter baffles?


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## gregzoll (Dec 25, 2006)

You could try by going from the outside in. I would wait until it starts to get cooler outside, before attacking this. It may end up involving one person in the attic and one outside, removing the Insulation batts out of the way, then sliding the baffles in, and have the person inside, then staple them.


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## brendelac (Sep 19, 2014)

I showed my newb-ness on the last paragraph of my last post. I assumed that when it comes to soffits, there is a standard width, either 10 or 16 inch that building codes specify and that you buy whichever size applies to your home and then install 8 foot lengths at a time. Since my soffits are 22 inches, I thought I might be SOL, but now I see that they are installed by cutting the 8 footers into 22 inch pieces and then installed side-by-side. The stucco on the sides of my house is right up to the plywood soffits. By removing the plywood, I'm sure to loose some stucco. Does it come apart in little bits or big chunks? 

My attic is a sauna right now with outside temps right around 100.


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## gregzoll (Dec 25, 2006)

Use a 4" cutting wheel to cut the stucco away from the plywood. It is 78 outside where I am, attic is 90.


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## brendelac (Sep 19, 2014)

Funny thing is, today, I have almost the identical scenario as you - 80 outside, 90 in the attic. There is a pretty strong breeze blowing through the gable vents though. Thanks for the tip on the cutting wheel.


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## Windows on Wash (Aug 30, 2011)

20 degree delta across the roof isn't bad at all. Its when you get 90-100 temps outside and it is 150 in the attic that you know you have problems.


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## gregzoll (Dec 25, 2006)

Windows on Wash said:


> 20 degree delta across the roof isn't bad at all. Its when you get 90-100 temps outside and it is 150 in the attic that you know you have problems.


I would get up to around 150, if I had the original vents that were placed too high up by the peak.

Even with the Power Vent, the highest that I saw it get, was around 115. Now with the proper venting, no power vent used. I am seeing at max around 105. Of course we have not had many hot days.

Right now outside is 81, feels like 84, Attic is 98. It actually has been a cool rainy Summer for us here in Illinois. My backyard is starting to look like a Cow Pasture that has not had any cows in it for a while.


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## brendelac (Sep 19, 2014)

Windows on Wash said:


> 20 degree delta across the roof isn't bad at all. Its when you get 90-100 temps outside and it is 150 in the attic that you know you have problems.


I think that is my case. It was 95 outside a few weeks ago and I was using my outdoor thermometer in the attic which only goes upto 125 and the needle was maxed.


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## gregzoll (Dec 25, 2006)

brendelac, I use a Radio Shack Weather station with remote sensors for my basement & attic readings. You cannot get the one I have, but Scientific makes one pretty close, with a different style of sensors.

Batteries last around two years for the sensors and weather station. I keep it on the end table where I sit. There is usually a 3-5 deg. difference from where it sits, and where the thermostat for the hvac, when a/c is on.

The good thing about the remote sensors, is that you do not have to keep crawling into the attic.

There are also some units that you can plug into a USB port and pull the readings into software on your laptop.


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