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Attic vent fan

Blaze626's Avatar

Join Date: May 2017
Posts: 41

05-27-17, 08:05 PM   #1  
Attic vent fan

There appears to be plenty of controversy about installing a powered attic vent fan. My house has one mounted but not wired in the gable vent.
I'm tempted to try to use it because the house gets hot and hotter into the evening after outside cools.

I'm sure this is something like a substandard attic insulation situation. My understanding of the controversy of these fans is that they are a band aid for a more fundamental problem (e.g., insulation).

Is there more to this than I'm getting? Since this thing is already installed, should I wire it up and use it until I can get an energy audit and work on the insulation problems? Is there a downside to these?

Thanks so much everybody

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ray2047's Avatar
Group Moderator

Join Date: Mar 2006
Posts: 32,374

05-27-17, 08:56 PM   #2  
because the house gets hot and hotter into the evening after outside cools.
Sounds like an air conditioning problem but yes you could hook it up and see if it helps. You might put a remote read thermometer in the attic to see if the attic temperature drops when the fan comes on. You can always disconnect if it doesn't help.

I can explain it to you, but I can't understand it for you.

Bud9051's Avatar

Join Date: Oct 2008
Posts: 9,772

05-28-17, 04:16 AM   #3  
There is a down side with the standard house. Even with good ventilation to allow replacement air to enter a fan will create a significant negative pressure in the attic. Without proper air sealing between house and attic that negative pressure will cool the attic with the air from the house. Now, that is just a dollar cost that maybe is acceptable and it can be minimized by addressing some of the major leakage points.

When you do address the insulation portion you should also address as much of the leakage as you can. Referencing a standard home there is something like a 12" x 12" hole into the attic, that is from adding up all of the small leaks.


sirk98's Avatar

Join Date: Jan 2014
Posts: 378

06-20-17, 08:38 AM   #4  
wow. This is in line with what I am suspecting my issue might be.

I posted a thread in two other locations on this forum (here is the ATTIC FAN topic I opened)

Is the point of an attic fan simply to assist in moderating temps in the house?. Considering disabling mine

Apologies for thread hijack. This seems very much in line with my chimney issue...

Sunburn's Avatar

Join Date: Oct 2017
Posts: 30

01-15-18, 06:25 PM   #5  
I have an attic fan and gable fan, the gable fan isn't used at all. I'm considering removing it as the attic fan works well on hot days, I've also read the same articles about gable fans causing issues. I normally turn the attic fan on for 30 minutes in the early morning with downstairs windows open, it cools the entire house up until the hottest part of the afternoon when the AC kicks in. The attic insulation might be something worth looking into if you need more, or have gaps to seal, plus it'd benefit you in cold seasons.

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