attic ventilation question!!!

[oonighttrain]

its hotter then he!! in my attic, my electric bill in the summer is about $350..
is a roof mount fan better than a gable mount? im being told it is..

any input?

thanks!

 

[PCDOC]

Hot air rises, so yes the roof mount will be better.

 

[xrated]

move out of FL and you won't have to worry

 

[ThrillSeeker]

From my experience, roof mount is better than a gable... but either is better than nothing....

Our garage temps were always 10+ degrees hotter than the outside temps, so during the summertime in Arizona it would be 100-110 outside and 110-120 inside the garage... needless to say before the gas cans/containers exploded, I put two solar powered attic fans on the garage roof and the temps now are always about 10 degrees cooler than out side temps...

Gable fans need to pull/vent the air horizontally while roof mount allows the air to flow/vent vertically (naturally) up...

 

[hilinerider]

got rid of the noisy roof mount fan when i reshingled the roof and put in a ridge cap vent, works better and doesn't use juice

 

[yammadog]

Attic fan.....but FL IS the problem....it's too stinking hot and humid!!! I went to my buddies place in Juniper for July 4th and haven't been back in the summer since!!!

 

[touchofgrey]

I've installed several thermostat controlled attic fans Jesse. Most popular in Can. is a Nutone. I would suggest if you go this route get your electrician to install a separate switch somewhere near your attic access, that way you can shut it off @ night if the noise is bothersome. I usually set the stat around 85 made a world of difference in my house, my customers all seem to be happy with their performance too. That's my .02

 

[Jeff C]

I used to install both types of fans when I used to insulate attics.

You have to remember this:

In either situation, you want to have the air flow in through the soffits, and out through the roof or gable(s)

I can't count the number of homes that had inadequate or blocked soffit vents. So first of all, make sure the soffit vents are all open.

Next, make sure that which ever option you go with (Gable or roof mount fans) you are not sucking air out of the attic with a fan, and it is being made up with air from a roof vent that is too close to the fan pulling the air out of the attic.

I am not a supporter of the gable type. If you are putting a fan at both ends, the middle of the attic tends to not to exchange air. You are pulling air that is trying to go upwards, sideways. The gable fans tend to pull air from the soffit that is nearest the gable, neglecting the center of the attic. You need multiple fans if your attic is of any size, and pulling fromt eh top of the attic, in multiple locations, will flow aire more completely through the attic, than gable.....

They make a solar powered attic fan now. Those cannot run at the same CFM as a AC powered one, but if you replace all the existing roof vents with these, it will do a good job, and no wiring needed! Solatube makes these I think? Check the website and determine the CFM flow of these things.

A solar fan every +-20 feet should provide good air flow and move that heat out of the attic.

http://www.solatube.com/homeowner/solarstar.php

 

[oonighttrain]

Next, make sure that which ever option you go with (Gable or roof mount fans) you are not sucking air out of the attic with a fan, and it is being made up with air from a roof vent that is too close to the fan pulling the air out of the attic.

http://www.solatube.com/homeowner/solarstar.php

my whole soffit its vented(around the whole house).. next question is where i put the vent/fan on the roof..

someone else posted they ledt there thermostat at 85 degrees. i think ill have to set mine somewhere around 120.. im guessing.. its 95 out here during the day, has to be somewhere around 120 or so in the attic.. ill put a thermometer up there and let you know..

 

[Jeff C]

Nighttrain:

95 outside can easily get temps up to 140-160 degrees in the attic. Trust me, I have several hot summers swimming around in Fiberglass insulation up in 140+ degree attics to prove it.....

I did a bit more research for you. Those Solar powered vents are $400-600 depending on CFM etc. Most models are 800CFM

In my opinion I would go with two powered ones.

Lets say you have a 100' ridgeline and three vents. I would take out the outer two and put in powered vents, then plug up the center vent with cardboard stapled to the bottom of the roof deck. You dont want the two fans getting their air from the center vent, you want it coming from the soffits.

I would set the thermostat at 110 degrees. They will run most , if not all the summer but frankly, that is what you want. You will spend much less on AC and barely more on your electric from running the fans.

We would routinely get 10+ years up here in Minnesota on a fan motor. They are easy to replace, and use common motors found at any electrical supply shop.........

 

[oonighttrain]

jeff,
the whole soffit is vented.. not just a few vents.. the whole thing..

i put a thermometer just above the ceiling in the attic at 3:30 today.. it was 115 degrees.. in other words, im sure it was alot hotter at the highest point of the attic.. im gonna get 1 fan to start with. i guess ill put it over to one side of the roof incase i get another..

 

[Mjunkie]

No one has mentioned the whirly-birds, but that is what I have on my roof and they don't require power. I know the whirly-birds don't look too good, but they made a big difference on my house and they have a lifetime guarantee on the ball bearings. You'll never replace a motor or have to do anything to them. I'm no expert but they are what were suggested to me above the powered ones for the reasons I've stated. Just a thought.