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Attic Ventilation

I currently have attic fan over garage, I need more ventilation here in Florida. The house is "L" shaped, from the garage it goes back @ 50 ft then the "L" goes left. Should I put in another full Gable vent to pull more air through the attic from the end of the "L" or a straight on vent and let the fan pull the air through or just open up more of the soffit i.e. put in some bigger vents around the back of the house.


Timothy Miller
Re: Attic Ventilation

Howdy, is there soffit,eve vents in the roof? any other vents other then the garage fan in the roof?

Re: Attic Ventilation

You will first have to calculate how many cubic feet of air you have in the attic, and then get an attic fan large enough (fans are rated in cfm (cubic feet per minute)); length X width X average height to get cubic feet; the fan has to replace the total cu.ft. of air in the attic every 5-6 minutes; this will remove the heat from the attic & make the house seem cooler, especially if you will be using air conditioning; large gable exhaust fans can be noisy, especially if they face the street or are close to a next door neighbor's back yard/house; noise rating should be on fan; 4 blades are better than 2 or 3.

A larger 3-speed control fan may need a stainless steel louver (adjustable) arrangement with a screen to keep out insects & critters; even larger attic/whole house fans 3-speed control mounted on a gable (cfm calculation) can cool down the entire house if you have periods of cool nites and not too hot days, which would save on AC expenses; exhaust fans lose effectiveness when temps climb above 80 degrees or it is humid out.

You Tube has some good videos on different attic/house & attic fan combos; this can be a DIY project, but a HVAC or Roofing tech/installer may be a better bet.

Google "You Tube installing whole house gable attic fan", or "How to use a whole house fan: 7 steps", or "Attic fan frequently asked questions"


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