# Question about cooling an attic



## artys_only (Mar 29, 2005)

So here the question , I have a two story house about 2000 sq ft , on my roof I only have a whirlybird vent and soffit vents , seams like I have no draw to pull the hot air from the attic , I want to put two or 4 of those solar attic vents on the roof to help draw out the hot air , any one ever done it ? Is it hard to do it with a existing roof ? Do you just pull cut a hole up pull up the shingles and slide it under and nail it down and roof cement it around edges ? Any help would be great full !


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## RB II (Feb 26, 2009)

The key is to get fresh air circulating in the attic from the soffit vents to the roof vents (whirlybird). Almost without exception, there is no path between the two. To fix that buy some 4" lightweight PVC pipe. Cut it into 3' lengths. Push it between the top plate and roof deck of the exterior walls. Space out as close to the soffit vents as feasible. The heat convection alone will draw large amounts of air.


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## FINNFOWLER (Sep 2, 2004)

HydraSports said:


> The key is to get fresh air circulating in the attic from the soffit vents to the roof vents (whirlybird). Almost without exception, there is no path between the two. To fix that buy some 4" lightweight PVC pipe. Cut it into 3' lengths. Push it between the top plate and roof deck of the exterior walls. Space out as close to the soffit vents as feasible. The heat convection alone will draw large amounts of air.


Could you take a picture or draw this up? I am not comprehending what you are explaining. I only have ridge vents.


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## artys_only (Mar 29, 2005)

There is a gap from the soffit vents so air can move it just doesn't , I figure by placing a couple of these on the south and west side it would help draw the air up and out , making more air flow in the attic making it cooler ?


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## jtburf (May 26, 2004)

artys only said:


> So here the question , I have a two story house about 2000 sq ft , on my roof I only have a whirlybird vent and soffit vents , seams like I have no draw to pull the hot air from the attic , I want to put two or 4 of those solar attic vents on the roof to help draw out the hot air , any one ever done it ? Is it hard to do it with a existing roof ? Do you just pull cut a hole up pull up the shingles and slide it under and nail it down and roof cement it around edges ? Any help would be great full !


 For starters you do not have enough soffit vents and I have never seen your house. Why you ask, no builder ever puts enough in.

Get in the attic and pull the insulation away from the roof between the joist, then add 100% more soffit vents and staple them in place along all sides of your eves.

Two problems exist. 
1 builders never install enough venting to properly vent an attic.

2 insulation crews fill the gap between the joist with insulation thus blocking any air flow that is even possible.

Attic breeze makes some real nice solar fans, http://www.atticbreeze.net/

See the picture below.

John


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## GT11 (Jan 1, 2013)

What jtburf said...

To cool that space you need air exchanges, which means you need enough intake vents and enough exhaust vents. It all comes down to the surface area of the vents. If you only have one whirly brid, it sounds like you don't have enough exhaust area even without knowing the sq footage of the soffit vents.

I don't know the calcs off hand, but if you search the net, you can find the vent area needed (intake and exhaust) to cool that size attic.


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## artys_only (Mar 29, 2005)

*soffit vents*

there seam to a lot of soffit vent be a lot on the house looking at them last night they are older and have been painted over this might be causing some of the restriction, I think I will replace them and then look at the exhaust , is there any better soffit vents to use ? the one that are one the house are like a return vent in the house with screen to keep bugs out , I think they may be clogged ? and suggestions .


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## GT11 (Jan 1, 2013)

I am about to replace the ones on my lake house and they are like yours. I will probably change my entire soffit to vinyl and use the soffit material that has the small holes in it. I will have to do a little more research before I do it though. For the exhaust, I like the ridge vents but you have to have enough of a ridge to do it.


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## RB II (Feb 26, 2009)

IMO, roof replacements/repairs such as adding roof ventilators are marginally DIY type projects. #1. It is dangerous on the roofs today, LOTS of slope in them. #2. Incorrect installation can cause major damage down the road. Be sure you understand the installation and use the right materials. Installing a vent on a new roof is MUCH less complicated than on an existing roof. IMO, far too complex to easily explain here.


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## 41082 (Dec 19, 2008)

Solar vents are very expensive. Easy to install. Make sure to set your skill saw to just over 1/2" so you don't cut your rafter. Obviously best to center cut between rafters. Make cut out according vent specifications. then you may have to loosen 1- 2 shingles above that cut out to slide vent up and nail properly. Then you can trim the shingles above and to the sides to fit correctly. We only use NP1 for all our vents and joints. Roof cement is ok for awhile but will get brittle and crack eventually. If you have enough ridge I would consider ridge vent first. then add a vent or 2 as needed hope this helps. www.cinchroofing.com


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## artys_only (Mar 29, 2005)

*Replaced soffit vents today !*

They were clogged the screen was on most of them , so I replace 11 of them back and two sides of the house . They are non on the north side of the house , I was in the attic to check temp and it was 85 deg today ! There is a ridge vent about 6.5 feet long on the ridge . Also it has two whirlybirds on each side of the peak that are working , it still baffles me why my attics so hot .

Last thing is on the one side the installation is pushed up towards the soffit on some of the vents two or 3 on the east side looked blocked .

This is my last hope ? Any other ideas ?


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## jtburf (May 26, 2004)

Add 2X more vents....

You simply cannot have enough intake.

Make sure the ridge vent has a 3/4" to 1" opening.

I have 40 continuous ft on both sides of my house and 20-30' on the back.

It make a HUGE difference.

They are cheap and very easy to install..


John


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## misbhavn (Nov 19, 2010)

I had my whirlybirds removed and added ridge vents when I replaced my roof and it made a huge difference...to the tune of about $100 per month in the summer.

I was always under the impression that you shouldn't use whirlybirds and ridge vents together. It had something to do with the whirlybirds messing up the flow. Just what I was told at some point in time as I'm no expert.


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## saltwatersensations (Aug 30, 2004)

artys only said:


> They were clogged the screen was on most of them , so I replace 11 of them back and two sides of the house . They are non on the north side of the house , I was in the attic to check temp and it was 85 deg today ! There is a ridge vent about 6.5 feet long on the ridge . Also it has two whirlybirds on each side of the peak that are working , it still baffles me why my attics so hot .
> 
> Last thing is on the one side the installation is pushed up towards the soffit on some of the vents two or 3 on the east side looked blocked .
> 
> This is my last hope ? Any other ideas ?


Check all of your duct work and make sure you dont have hot air leaking into your attic. Assuming you are running the heater.


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## MoonShadow (Jun 3, 2007)

Do you have tech shield installed? Makes a lot of difference in attic temp.


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## meyerman (Aug 23, 2005)

A radiant barrier does wonders to block out heat in the attic. I put radiant barrier foil in my attic and made the world of difference. It is easy to install with a stable gun to secure to rafters. Had A/C repairman doing annual ispection of ac and he was amased how comfortable it was in the attic. I have a 3300sqft house and foil cost about 500 dollars plus MY labor


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## JFolm (Apr 22, 2012)

Do companies offer a spray on radiant barrier?

Also, 

I have gable vents on the front and back already. Would a ridge vent benefit me?


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## jtburf (May 26, 2004)

JFolm,

Yes there are companies that spray radiant barrier however keep in mind your cell phone coverage in you home will be horrible at best, every house I have been in with radiant barrier be it spray in or plywood you have to styand by a window to get or make a call...

No need to add a ridge vent if you have gables, its on or the other.

Again add as many soffit vents as you can fit, insure they have no obstructions and insulate the whole attic with what ever type of insulation you choose.

This is simpler than rocket science.

John


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## g_mo (Jun 27, 2005)

I've heard and read from various sources the you can over exhaust an attic. Meaning if more is venting out than is coming in from the soffit it can pull from inside the living area even down to the slab and pull moisture up into the living area. If that's true, can you over intake an attic if there's not sufficient exhaust and end up pushing hot attic air down into the living area?


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## jtburf (May 26, 2004)

g_mo said:


> I've heard and read from various sources the you can over exhaust an attic. Meaning if more is venting out than is coming in from the soffit it can pull from inside the living area even down to the slab and pull moisture up into the living area. If that's true, can you over intake an attic if there's not sufficient exhaust and end up pushing hot attic air down into the living area?


 No, as long as your not using a mechanical means to draw in air with no means for it to exit your not able to do that.

The venting system is based on the theory of heat rising, as hot air rises it draws in cooler air from outside the attic this displacing existing hot air with normally cooler exterior air.

John

John


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