Several years ago I needed to check and see if the soffit vents were open. The home had vinyl soffit install and vented panels were used. Yet we've seen these vents put over non existent holes just as our Angies's List customer in Plano had a soffit vent over a non hole. Even if there is a hole the size is too small and here, I hate to say, size matters. The 16"x4" soffit vent has 26 NFA in inches if the hole above it is cut right and not obstructed. The 16x8 soffit vent has 65 NFA.
The screen on the top side will obstruct with dust and must be periodically be cleaned, usually with forced air. If vinyl, aluminum, or steel soffit panels are installed and the soffit vents are not removed, they will clog with dust.
You can go outside and look and see the shape of the hole cut on the other side by the dust pattern. No dust pattern means no hole, the vent is new or has been cleaned recently.
I went into the attic, turned off the light, and had the attic access fold out stairs closed behind me to maximize the darkness. Alone in the dark I heard and felt a cold and clammy wind. Scary? air conditioning was being sucked into the attic as a result of the Venturi Effect.
A a minimum the attic access needs to be weatherstripped and the top side insulated. Second best are the igloo like covers that can be set over the pull down stairs to conserve climate controlled air. The best way is to have the access in the garage or some other non control environment.
If the entrance is strategically placed in the garage the hole can act as a large soffit vent and help keep the garage from super heating. I homes with no overhang, a power vent can be placed on the gable furthest from the garage and the two other holes, the other gable and the open attic access, can be used as intake.
We've actually built access in the garage with a screened cage set over it to keep the critters and birds from attempting to explore the attic.
If you have a hallway or closet attic access, go feel of it and you'll see what I mean.
Jon Alan Wright
Jon Wright Roofing, Siding, and Windows
1915 Peters Rd., Suite 310
Irving, TX 75061
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