It will pull primarily from the attic vents, not from the home.

Just for the record, attic fans only work if the air outside is cooler than inside and/or less humid. Then merely turn on the fan and open your windows. Literally cuts the cooling/heating season by 20%.

Otherwise a better (cheaper) upgrade to cool an attic would be a radiant barrier, installed with enough air on either side. Just be careful as the regular grade Home Depot stuff isn't that good and yet priced expensively.

As Jake said, the air is going to short circuit your desired flow pattern and pull out of the attic. You could put a large grill in the attic and have a 30" duct run to the gfan at the gable end. I'd look at Panasonic and Tamarack Tech as well.

Where do you live, and do you have a central AC system?

I do not like mine; it is too noisy and I never use it.

OK, you've convinced me--we'll put the fan in the ceiling (attic floor), not the gable.

We live in Baltimore. We've used a large Air King window fan (designed to exhaust the whole house) for years (in the evening, to exchange hot indoor air for cooler outdoor air). We've now moved into a bigger house, so we figure we'll get something more powerful.

Charlie, are you saying that a Triangle/Dayton fan is too noisy, or whole house fans in general?

Do you have mechanical cooling, conventional AC? If you do you might be shooting yourself in the foot when you have to remove all the moisture accumulated overnight. Baltimore is not exactly an arid place.

We don't have central AC. We have window units, which we only use when its very hot. We're planning to replace those with a ductless Japanese-style AC in the den and kitchen and retreat to there on very hot days.

All that advice and no mention of existing attic ventilation??? What gos in must go out. Translated means that unless you have far more square inches of attic vents than normal,a ceiling installed fan will perform poorly.
You might even create health hazzards if the attic has insufficent exhust vents. The fan creates a high postive pressure in the attic and negative pressure inside living area. Air leaking back into living area will be heavly contaminated with dust,insulation particals and possibly worse. The conventional method of overcoming this is large movable shutters in one or more gables. Your origional plan of mounting fan in gable completly eleminates issues of pushing dirty attic air into living area.

It sounds like you want to install a mini-split AC in the den and kitchen. This would mean you would close all the windows. You must open all you windows when you run the whole house fan. This would be working against the running the AC during the day.

Whole house fans were something people used if they had no air conditioning. The windows were kept open all the time except during heavy rain storms. If you have AC units you have a good chance of someone turning on the fan with the windows closed. This could cause back drafting which is a potentially dangerous condition. You need to think about this carefully.

Klem1: If we install the fan in the attic floor we would have to make sure to install the necessary vents/soffits in the attic to exhaust the air. But if we install the fan in the attic gable, it seems we'd have to install a 30" duct from the fan to a shutter in the attic floor and solve the problems of installing a fan that was designed to be installed in the floor (horizontally with an internal shutter) in a gable (vertically with an external shutter). The former seems easier than the latter, doesn't it?

Mike: Thanks for your advice. We'd only plan to use the AC occasionally (when it's very hot) and only in one area (the kitchen/den). We would have to open and shut windows.

I wouldn't know which is easier because it depends on several existing conditions. I will however offer,sofft vents are intended for air to ENTER ONLY,gable and deck vents are intended for air EXHUSTING ONLY. There will naturaly be small amounts of air flowing in and out both at times. Vents are often covered with smaller mash(esp soffit) than desired. Small mash window type screen tends to clog with dirt and debris making them non-functional. For what you are doing I wouldn't expect it nessary to add soffit vents but inspect present ones and change to 1/4tr inch screen or no screen if wasp and hornets aren't a problem in your area.

Putting up 1/4" screen may violate the GSWDA.

(Grey Squirrels With Disabilities Act of 1998 as amended.)