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-   -   Gable fan and Whole house fan (http://www.diychatroom.com/f9/gable-fan-whole-house-fan-927/)

jckkcj 08-17-2005 10:14 PM

Gable fan and Whole house fan
 
I live in So California, temps range from 50F to 100F. We have a 40 year old, two story, 1900 sqf residence with two 14x18 inch gable vents in each end of the 900 sqf attic.

I need to move the air in the attic and would like to install a gable fan. We do not have AC and do not plan on getting it anytime soon. We would like to use a whole house fan to cool the home in the afternoon. My problem is this:

The whole house fan needs to exhaust through the roof, but I do not believe I have adequate ventilation. Could I do either or both of the following:


  • Bypass the thermostat control on the gable fan and connect it with the whole house fan? So when I turn the WHF on, the gable fan would also start?
  • Install a second gable fan on the other vent to be controlled by thermostat during the hot days when I do not want to use the WHF until in the evening?
I have looked at this website for a couple of hours and seen many references from Grumpy, HouseDocs, Teetorbilt, Aaron B., Glasshousebltr, and others. Unfortunately, I am unable to find an answer to my question.

Thanks in advance. Jason

Teetorbilt 08-19-2005 12:30 AM

Gable fans are for removing attic heat, the CFM is much different from a whole house fan. You can replace one with the other but should have to increase to opening size, 14X18 is pretty smal. High velocity fans are available but consume more energy. The final step is installing the ceiling vent(s). It/these should be placed most central to the house for the best draw. They sholud also have dampers to semi close off rooms not in use, closing off rooms completely could result in mold or mildew.
I grew up in the Bahamas and FL, I left home the same year that the house was A/C'ed. Home was a '62 Buick Invicta stationwagon, with A/C! Gas was $.19 a gallon and the 455 Wildcat could idle all night.

K2eoj 08-19-2005 12:47 AM

Here is my opinion.

1) Gable fans are unnecessary if your attic is properly vented. It is fairly easy to install roof vents or ridge vents to come up with the proper square inches of ventilation. I'm sure you are lacking sq. inches of ventilation according the the code book I use, (UBC), but I think venting can be a different with different houses and areas. Where I live some places get driving snows that can fill an attic with to many vents. Another thing I don't like about powered vents on thermostat controls is that if there is a fire and these things sense heat they turn on and make a bad situation worse. I was working on a relay connected to a smoke dectector that would shut the power down in case of smoke. I was not happy with the results and gave up. I own 7 powered vents on properties and am working at phasing them out. Right now I at least have a switch on them so they are totally disconnected during the cooler months.

2) I have a whole house fan and love it. I think if you get some more vents in your attic you will have no trouble exausting your whole house fan. Again in my opinion fire is an issue with a fan that size and is something I consider say when leaving the house unattended for several hours. Do a little research before buying. i installed a direct drive for a friend and found it was much louder than my belt drives. i'm not sure why. I also found the louvres would flap in the breeze when I was trying to heat the house so I installed drop down doors with weather strip to close the fan alltogether for the winter months.

I'm not up on what is currently out there in the industry and my opinion is based on what i've done in the last 10 to 20 years. Hope that helps.

I've been working on some different roof vent designs that i've been happy with that i'll post on a different thread. HS.

jckkcj 08-19-2005 01:10 PM

Teetor and Hammer, thanks for the input.

From what you've said, I am going to have a go at the ridge vent and it should give enough exaust venting for the whole house fan. I will just forget about the gable fan.

If anyone else has any advice, please feel free to post.

Jason

AaronB 08-19-2005 10:30 PM

I say have an adequate attic ventilation system, and make sure you have soffit vents, and then the WHF will force tha attic air out when it goes on. When it is not on, you still have adequate attic ventilation.

jckkcj 08-20-2005 11:37 AM

I probably did not explain it before, but part of my problem is I cannot install soffit vents. The roof meets the wall below the ceiling line.

I called MasterFlow and they told me the best idea is a ridge vent and to open up the small gable vents to large gable vents. The gable vents will be exhaust while the WHF runs and intake for the ridge vents when the WHF is not in use.

Let me know if there is anymore input. Thanks.

K2eoj 08-21-2005 11:02 PM

Quote:

Originally Posted by jckkcj
I probably did not explain it before, but part of my problem is I cannot install soffit vents. The roof meets the wall below the ceiling line.

I called MasterFlow and they told me the best idea is a ridge vent and to open up the small gable vents to large gable vents. The gable vents will be exhaust while the WHF runs and intake for the ridge vents when the WHF is not in use.

Let me know if there is anymore input. Thanks.

That sounds like a really good plan.> Not to get things too complicated here but I experiment with pullling a few cfm of cool air from a basement, or crawl space, or sometimes even living space into the attic space during the heat of the day. The cool air will lay low in the attic and make a buffer between the hot air and the living space. I've been really happy with the results. I do live in a climate where the night temps are 20 to 35 degrees cooler than daytime temps so pulling in and storing some cool air is not a problem. HS

andy9 08-26-2009 09:34 AM

I'm so close to purchasing the Attic Aire Whole Fan, it's very inexpensive yet a real value for money. Who had tried this before?

Ed the Roofer 08-26-2009 01:55 PM

Quote:

Originally Posted by jckkcj (Post 3990)
I have looked at this website for a couple of hours and seen many references from Grumpy, HouseDocs, Teetorbilt, Aaron B., Glasshousebltr, and others. Unfortunately, I am unable to find an answer to my question.


WOW!! :eek:

You really dug way back into the old archives, didn't you?

When the Whole House Fan turns on, it will exhaust out of the space from the Gable Vent Fan without that unit even having to be turned on, so don't worry about adding any more.

Ed


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