Old house attic ventilation update

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UserJ

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I had new shingles put on the roof of my 1917 house around five years ago due to the old roof leaking, but nothing was ever mentioned about ventilation. We don't get much snow here in west Texas, but the extreme heat of summer can cause the attic temps to be fairly high, lowering the effectiveness of cooling inside the house, as well as probably shortening the life of the shingles. As I learn more about attic ventilation I'm concerned about this, so I'm looking to update it.

The current system is gable venting, consisting of a metal gable vent(not sure of size at the moment) at the front of the house, and a dormer with built-in wood slat vent on the hip roof at the rear of the house. That's it. There's no soffit, therefore no soffit vents, and the eaves are blocked with solid blocking, therefore there's no intake at all under the eaves, and there's no ridge venting.

I'm concerned that the gable vent system isn't efficient, so I'm looking to block it off and switch to undereave intake with turbine exhaust. My plan is to drill three 2" holes in all of the undereave blocking around the house, and then install two 14" turbines up near the peak. Does this seem like a good idea, or should I just leave it all alone with the gable vents?
 
Welcome.
And after drilling all those blocks, what is your method of screening them to prevent infestation, and how will that affect the aesthetics of the dwelling.

I would leave the existing venting and install a whole house vent system, where you draw cool air in and exhaust into the attic, forcing the hot air out.
 
Thank you for the welcome.

I was thinking to staple screen over the holes temporarily, and then possibly switching it out for screened inserts over time. The neighborhood is old, and nobody's house is winning a curb appeal award anytime soon, so undereave aesthetics is not as much of a concern as functionality.

Do you happen to have any recommendations for whole house vent systems? Everything I've heard about active venting/powered fan venting has mostly been that it's not recommended for an older home like mine, especially with an attic that's not well-sealed and well-insulated.
 
Leave the gable vents alone.
Or add a power gable vent fan at one of them.

Your idea of adding vent holes under the soffits is good.

You should go up in the attic first, to make sure that the holes will actually connect with the attic air space.

And clean out any insulation that is laying on top of the soffits.

You can get little round vents called muffin vents, in plastic or aluminum.
They have louvers, and some also have a wire mesh for insects.

You just drill a hole with a hole saw, typically about a three inch hole, and push the vent cover up into the hole.
They lock themselves in with spring tension from little clips that grab the round hole.

You can add dozens of these little muffin vents.

You can also cut rectangular cutouts with a jigsaw, then attach rectangular aluminum vent covers with louvers and a mesh screen.
 
I'd be very careful about removing and replacing the blocking with off the shelf screened vents, because you don't know what the blocks have to do with any, or if they do at all, roof diaphragm shear.

The general rule of attic ventilation is 1 in 150, IE, if the attic above the dwelling is 300sq', the attic ventilation would be 2sq'.

I've installed several hundred whole house vent systems in the LA basin, southern CA, in single and 3 story single family residences, 1 as old as 1930, and if you pay attention and operate them correctly, they preform rather well, however nothing like an A/C system, just a lot cheaper.

I can tell you the optimum operation, but you have to adapt to your conditions.
 
I'm very familiar with the attic space, so yes, I've already been up and confirmed that the holes will connect with the attic air space.

There's nothing to cut with a jigsaw, as there's no soffit. It's open under the eaves, with only the blocking separating the outdoor air from the attic space.

I don't intend to remove the existing blocking at any point. My idea is to drill holes and cover with screen. I may possibly replace the screen with 2" round push-in vents in the future, but I think just screen would be an inexpensive solution for now. The blocking is only 2x4, so I figure 2" holes would probably be best, as 3" may be cutting it kind of close.

I did a Google image search, and attached are a couple of photos I found for example.
 

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Sorry, I had skimmed and missed where you said you have no soffits.

Snoonyb, I think she has air conditioning, so a whole house fan would suck that right out.

A roof vent fan or gable vent fan would pull hot air out of the attic.
 
I'm a he, but no worries, I'm not offended. 😄

I currently have an evaporative cooler, but I am looking to convert to AC soon.
 
The most recent whole house system I installed was in a 3600sq' ranch converted to a 3 story TUDOR, with 3, 3ton AC's. It is a 48" fan and reduced the clients elec. bill by 60%.
 
Snoonyb, that sounds excellent.

Maybe the term “whole house vent” means something different in my area near Chicago.
Around here, a whole house vent fan is installed in the ceiling of the upper level, usually a main hallway or master bedroom, and pulls air from the whole house through the windows, and pushes it into the attic, which then also flushes hot attic air out through the attic vents.

These fans are usually only used in spring and fall, when they can cool the house enough to not need to turn on the air conditioning.
They can also sometimes be used only at night, during the a/c season, to cool the house and the attic with cool outside air.
 
We recently moved from Sacramento, California to Northern Alabama. In California, we had a whole house fan and it worked great. When the Delta Breeze came in around 5-6 o’clock every night, we could turn the A/C off, open a window or two (not too many) and turn on the fan to suck that cool Delta Breeze air in.
My question is, how would a whole house fan work in humid climates? The air in our new house is somewhat dehumidified by the A/C (although it’s still pretty humid). Turning on a whole house fan would suck more humid air into the house wouldn’t it? Is that a problem?
 
JEFF, that's the intended operation and how the system works, however I advise folks to open windows on the shaded side of the dwelling and preferably adjacent to a grassy or liberaly landscaped area of the yard, which are inherently cooler.

Some folks in ARIZONA, (BULLHEAD, WILLOW VALLEY) will often use a pre-cooler for their A/C's, which amounts to a cool water drip system across the A/C coils, on fan only.

RON, yes humidity is a concern, so it becomes a monitoring concern and adapting to the environ you're dealt with.
 
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