# Combining an attic fan with a ridge vent



## hdavis (Feb 14, 2012)

You can make things a little more simple and make the area somewhat air tight, and just blow a much smaller CFM of air into it. Think using radiant barrier that isn't a vapor barrier (or poke holes in it with an ice pick) to define the storage space, and vent to the attic above the highest storage point. Fewer possible issues.


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## hdavis (Feb 14, 2012)

MHElectric said:


> I think they work well. I just wish someone could advise where the best location would be to put one in combination with a ridge vent.



No joke, this is impossible to answer. IMO, your best bet is to install it and try ducting to different levels and see what happens to temp.


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## MHElectric (Oct 27, 2012)

hdavis said:


> No joke, this is impossible to answer. IMO, your best bet is to install it and try ducting to different levels and see what happens to temp.


That's actually a really good idea. This would be a great plan b if I don't get it right on the first attempt.


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## kiteman (Apr 18, 2012)

I think you have to make the fan big enough so it has to draw air through the soffit vents as well as the ridge vents to be effective. Put it wherever it's convenient. If you finally figure out that we're trying to tell you not to have a fan and ridge vents, then put it up high after you close off the ridge vents. 

I didn't think sparkies were so dense.


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## MHElectric (Oct 27, 2012)

I'm going to bump this thread, and get things moving again...

What is the best way to completely seal up a ridge vent without making an ugly mess?


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## Tinstaafl (Jan 6, 2008)

A few cans of Great Stuff on the underside.


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## GoodStuff (Nov 10, 2014)

So, the answer has a lot to do with having proper ventilation to begin with...

I've ran into this situation many times - everyone loves to store things in their attic and too many attics are sweat boxes. In almost every case, I have found the soffit vents are either plugged and not breathing, or there is simply not enough soffit vent for the area to breathe properly. There should be 1-1/4 times as much "free space" venting through the soffits as there is vent space in the roof vents. Think of it in terms of intake and exhaust. There are Styrofoam inserts available that fit in-between the rafters and allow the soffit vents to breathe without the fear of insulation covering the duct space... I have also cut custom vent "breathers" out of 6" ducting that sat on the top of the soffit coverings to free up space for the soffits to breathe. In some cases more vent openings need to be cut into the soffits to achieve the 5/4 ratio of vent space.

Accounting for the opening size of the ridge vent AND the power vent is just simple math... compare that to the opening sizes of the soffit vents and you will have your answer - you can't draw more air than is available though, so justifying the answer without taking the soffit vent area into account is a mistake.


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## MHElectric (Oct 27, 2012)

GoodStuff said:


> So, the answer has a lot to do with having proper ventilation to begin with...
> 
> I've ran into this situation many times - everyone loves to store things in their attic and too many attics are sweat boxes. In almost every case, I have found the soffit vents are either plugged and not breathing, or there is simply not enough soffit vent for the area to breathe properly. There should be 1-1/4 times as much "free space" venting through the soffits as there is vent space in the roof vents. Think of it in terms of intake and exhaust. There are Styrofoam inserts available that fit in-between the rafters and allow the soffit vents to breathe without the fear of insulation covering the duct space... I have also cut custom vent "breathers" out of 6" ducting that sat on the top of the soffit coverings to free up space for the soffits to breathe. In some cases more vent openings need to be cut into the soffits to achieve the 5/4 ratio of vent space.
> 
> Accounting for the opening size of the ridge vent AND the power vent is just simple math... compare that to the opening sizes of the soffit vents and you will have your answer - you can't draw more air than is available though, so justifying the answer without taking the soffit vent area into account is a mistake.


So it sounds like you are recommending using both the ridge vent and the fan together, right?

Could you explain your method? Thanks!


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## builditguy (Nov 10, 2013)

It is improper to have 2 types of vents in the attic space. Ridgevent works good although it does nothing for humidity. Exhaust fan works good, but the motors tend to last about 10 years and 1 month. (just past warranty) Also, nobody realizes when the motor stops working. It may be years before someone notices.

Whenever you put in an attic fan, it will draw air from the point of least resistance. In your case, without seeing it, it will pull air from the ridge vent. I have seen people install attic fans near pot vents. (I don't know the current term, but they are the ones where you cut small round holes in the roof and put a cover over them) When the attic fan kicks on, it pulls air through the pot vent. If it's raining, it pulls the water through also.

It was mentioned to seal the ridge vent. If you are going to do an attic fan. I think you need to close off the ridge vent. Great stuff will work. You could also remove it completely and install new ridge cap.

I realize not all attic fans go bad after 10 years and 1 month. I have seen alot though.


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## GoodStuff (Nov 10, 2014)

Ridge vent and attic fan can work together as long as there is plenty of soffit ventilation to provide intake air. The trick is to mount the attic vent about 1/3 lower than the overall height of the space that you are working in.


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