Attic Gable Fan? Do or Not Do?

[Chaznsc]

So I hvae an attic gable fan thats apparently given it up. I was looking online at recommendations and came across more than a few commentarys against gable fans. It does seem that such a small fan couldnt make much of a difference.

What say you?

 

[K'ledgeBldr]

Gable fans, like power roof ventilators create an "active" ventilation system of the attic. What makes them work efficiently depends on where and how much "intake air" there is. In other words, if the structure has a ridge vent the gable fan will pull more air from the ridge rather than the soffit- making inadequate ventilation. If there is no ridge vent and there is adequate soffit vents (apply the 1/300 rule), you should have very adequate ventilation for the attic. But again, remember this is an active system that requires a mechanical device in which to operate properly. And that of course means that it will fail at some point!

On the flip side- a passive system relies on convection. Hot air rises; exits the gable or ridge vent and is replaced by cooler air through the soffit vents. There has been significant studies that tend to show that a ridge vent is a bit more functional than a gable vent due to the fact that the air is moving in a vertical direction. However, it's also been widely proven that prevailing winds can counteract either vent- depending on compass direction. The nice thing about passive systems- they don't break.

 

[mike93lx]

Is it intake or exhaust?

I have an attic fan that i never use. Don't like the idea of pushing humid air into my attic.

Ventilation is all passive for me. Ridge and overhang vents

 

[CombatNinja]

I would say that 90% of the installations I have come across do not work properly. The most common issue seems to be a combination of inadequate soffit venting area coupled with a grossly oversized gable fan that then proceeds to pull conditioned air up from the living space through every tiny crack and crevice that exists. The right way to do it is with a properly designed passive system.

 

[fsae0607]

Stick with passive. In my old parent's house, we got talked into installing an attic fan when we got the roof done. That thing was nothing but headaches. Always breaking.

 

[CombatNinja]

In my old parent's house, we got talked into installing an attic fan when we got the roof done. That thing was nothing but headaches. Always breaking.

Hope you got some new parents that have less attic hassles.

 

[fsae0607]

Hope you got some new parents that have less attic hassles.

haha luckily they also installed new dormer vents. We just left the attic fan unwired.

 

[isb cornbinder]

I have one of those turbine fans on the garage roof and two on roof of the house. The rising hot air drives the turbine fan and evacuated the hot air. These fans work really well. Zero maintenance, no electricity required and quiet. Our attic used to get so hot the shingles would melt. The ceilings in the house were quite hot, also.

 

[Old Man Roger]

Anyone else read the title in a Yoda voice? Just sayin.

 

[CombatNinja]

 

[SGKent]

I've had 2 or three of them and regardless the framing and making sure they did not back flow the cooling was not that much. They ate too much power and every couple of years the motor bearings went out. Then I added some passive low profile vents up high on the roof that were not visible from the street. I added an extra set of gable louvers on each end of the house and many more soffit vents, and a good Triangle made whole house fan. One can go in the attic on a 110F day and it is barely hotter than outdoors. One can turn the whole house fan on at 6am - 7:30 am and drop the attic temps into the 60's that helps keep it and the house cooler all day. There is less damage to the roof shingles and wood because it does not get as hot. I would never use a gable fan again. Several neighbors have whirly bird turbines which they say help but I've seen them come off in wind storms and expose the attic to rain. We are in the California Central Valley near Sacramento and I imagine my solution would not work in places with hurricanes or long cold spells.

 

[yeldogt]

What are you trying to achieve ?

Most attic fans create negative pressure -- this ***** conditioned air from the building. Also very bad in any area with radon.

Passive or none --- Passive in many cases don't work anyway. In my area we do unvented.

 

[Chaznsc]

I have one of those turbine fans on the garage roof and two on roof of the house. The rising hot air drives the turbine fan and evacuated the hot air. These fans work really well. Zero maintenance, no electricity required and quiet. Our attic used to get so hot the shingles would melt. The ceilings in the house were quite hot, also.

It’s not really a fan, but a vent, correct?

 

[CombatNinja]

Technically, yes, those are vents and not fans. They are not powered in any way but use passive convection. The real issue with them is that they are a) ugly and b) cause a roof penetration for every one you install which is a potential spot for a leak. I like to keep penetrations to a minimum. A continuous ridge vent with properly balanced soffit venting is really the way to go for passive ventilation.

 

[DC73]

More often than not, powered attic fans in any location tend to use more electricity than they save. Especially when compared to a proper passive ventilation system or a proper unvented attic.

DC