[Falchion14]

Hello All,

I just bought a 1980's house and I'm concerned that it doesn't have enough ventilation in the Attic. I live in Austin, TX where we have hot summers (100+) and mild winters(some freezing weather - no snow, but ice storms once every few years). My main interest is in keeping the attic from getting too hot in the summer and causing my A/C to work to hard.

It is a 1900 square feet 1 story house with a 2 car attached garage (~400 sq ft). It is a T shaped house. It has soffit vents along most of the outside and two gable vents (in the back and side gables, but not the front/garage gable). It does not have ridge vents or any other kinds of vents.

I'm thinking about installing a solar powered gable fan in the side gable or about installing a new gable vent in the garage/front gable and putting a solar fan there.

Do I need to worry about the gable fan sucking up the blown in insulation?

Does anyone have any thoughts on whether it would be better to add the gable vent and fan or just the fan to an existing gable vent? I'm concerned that the air above the garage is too static, although there are soffit vents on one side of the garage.

Any recommendations on kinds of solar gable fans?

Thanks in advance for your help!

Sincerely,
Stephen McCants

 

[jpike3211]

Ventilation

Hi Stephen,

How old is your roof and what kind is it?

The latest air ventilation technology was hardly used in residential structures until this century. If your house has never been re-roofed, it might not be too long before your house needs a new one. When you do replace the roof, you will be able to study your unique situation and decide which would be the best roof.

In the meantime, I'm not sure a fan is going to be useful in the summer. I was told to use mine only when temperatures are below 80 F, which is spring or fall. In summer, the fan would only be sucking in hot air and if you don't have enough vents near the top ridge, that hot air will only circulate inside and create a convection oven, baking your house.

You should probably consult a few roofing companies and perhaps even get a real roof inspection.

Jackie

 

[Falchion14]

Hi JPike,

Thanks for your reply.

The roof is brand new. I just bought the house and the previous owner had to put a new roof on to close the deal (hail damage had finished the old roof off). They scrapped it down to the decking and put a new 30 yr roof on.

Just to be clear, I'm not talking about a whole house fan that would pull air out of the house into the attic, but I'm thinking about a gable fan to pull in hot air from outside the building to replace the even hotter air in the attic.

 

[jpike3211]

Fan on gable

I'm glad it's a new roof, congratulations on your new house.

Yes, I understand, and frankly I wouldn't know, but to give you a reply:

My fan is located in the ceiling (or base of the attic) and pulls air from inside the house when windows are open, and the force pushes air upwards towards the decking and ridge, so it's an upward movement. The blades are horizontal to the ceiling.

What I think you describe is forcing the air inwards from the side (gable), blades being vertical, like the side wall, but the force of the fan blades will just make hot air circulate in the attic, if you don't have sufficient vents in the shingles at the top.

More modern roofing configuration will add a ridge vent at the very top, where the intake of air enters through soffit vents (eaves) and is exhausted at the top ridge vent. This is still an upward movement.

Perhaps you could tell us how many vents these new shingles have and if by chance you do have a ridge vent. You could install instead a ridge vent, but then a good roofer should calculate the amount of soffit vents you would need.

I hope the experts respond to this.

 

[texas16309]

I have a similar situation. My house is only 11 years old - two vents in the gables and continous soffit vents. However, I don't feel any of the hot air coming out of the gable vents. I also have no vents on the roof. I also have a radient barrier and my attic still get very hot. I can't belive the home builder didn't think of better ventilation. Any advice would be great.

 

[Falchion14]

Hi Texas 16309,

If I go through with my plans to add the gable fan, I'll let you know what kind of difference it makes. I'll have to stick a thermometer up there before I make the change and then afterwards. Fortunately, I have one of those wireless thermometers, so that shouldn't be too hard.

Jackie,
The gable fan I'm describe does go on the side on the house (just inside the gable vent) and is suppose to blow the hot air out of the attic through the gable vent. From what I've read you are suppose to completely close up the gable vent with the fan to make sure air only exits the house there. I'm just wondering if it will really draw air from the soffit vents or just from the other gable vent(s). Of course, if it gets the temperature down in there, that should help regardless, I suppose. Thanks for your thoughts. =)

--Stephen

 

[Gary in WA]

Here is some good reading: http://books.google.com/books?id=Z8...=book_result&ct=result&resnum=9#PRA1-PA604,M1

If you go with ridge vents, all are not equal: http://files.buildsite.com/dbderived-f/airvent/derived_files/derived20936.pdf I have a few more good sites if needed. Be safe, G