big exhaust fan with shroud encased in housing creates vacuum to exhaust heat

[bent]

I was reading a website once dealing with heatpumps and energy type stuff to do with house environment conditioning and I came across something which matched my needs and I do not know what this type of unit is called, and I'd like to research them now that I had to cut a hole in my top floor ceiling to drive away some squirrels.

It was a fan with a tight round shroud which is enclosed within a rectangular box frame which you install in the ceiling drywall on the top floor of a house where the heat gets too great in the summer. You open the inside winter flap and turn on the fan and it creates a vacuum which forces the air up into the attic and out through the vents in the roof.

I have already installed a ceiling fan in the area I want to install it in and it did nothing, so I need to try the big guns. Now the squirrels have left, anybody got any idea what I'm talking about. A name is a good start, as would be any info source. I also have to be concerned about whether or not I have sufficient vents on the roof to accommodate such a pump.

[AAllc.architects]

[bent]

Like wholehousefan.com; ah, thank you, Before you go too far, do you think I'd need extra exhaust vents on the roof. Its on a recent top floor addition not original to the house. I am unlikely to patch the hole in the drywall now, but am equally unlikely to solve the answer to this question myself, but I don't know if this could be a(nother) disaster.

wrote

[RicodJour]

Whole house fans move a _lot_ of air. The manufacturers' web sites or technical support help line will provide the specifics.

R

[bent]

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this is what I were planning on planning; now where to get the fan?

"bent" wrote

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I've got to ask a question now a see a snag.

under the lightly bolded heading

Use "H" Brackets To Provide Proper Support

at the same site above

The site says to put the fan above the truss, but I probably only have room to put it below since it is at the edge of the sloping roof. And my truss is in the middle of the the 34" wide hallwall (ceiling at the top of the stairs), so its above or below.

I can see putting the fan at the roof level, and anything closer to the house may not vacuum air out, but pull attic air in. Anybody see a problem mounting the 6-1/2" housing sticking a couple inches into the ceiling form above, rather than mounted above the truss? If its the same side walls, does it theoretically matter?

[bent]

perfect.

Why does "Whole House Fan" yield only Zinnser and humidifier at homedepot.ca? Actually thats what anything yields.

[Steve Barker]

You need 10 sq ft of exhaust for a 30" fan. Do you have vented eaves? Or add up the total area of your attic vents. Chances are, you'll need more for the fan to reach it's full capacity.

[bent]

Yes I just counted 2 screened roof vents, but exactly 1/3 of the soffit panel area is of the perforated type too, so theres lots of venting, weather it flows or not is another story.

Looks like I'll definitely be doing this, when I find a homedepot.com version of the fan/shroud/shutters up here.

But I am really perplexed for the design b/c my inside ceiling, the attic volume, the vented soffit, the roof, and where I'll mount some sort of casing are all within an arms reach. I don't want to do it all and find out it doesn't do anything.

There are 2 bedrooms on this top floor, and at hotter times you can feel the heat rise as you go up step by step. Round off a full degree per step when its hot!! I have big windows in both rooms on either side of the hallway. [Even] if just this upper floor gets cooled (fully flushed by cooler outdoor air) I'll be happy. But I don't know what to think.

[bent]

The hallway is 34" wide (maybe a code thing). Right at wall at the top of the stairs the roof slopes backwards, the outside is just through the wall. And there is only one 2x6" joist/truss right in the middle of the 34" (and

16" each way), but the ceiling drywall is not flush with it - theres a full 4" in between (insides) them.

"bent" wrote

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It also gets COld up here in winter

"bent" wrote, the outside is just through the wall. .... the roof, and where I'll mount some sort of casing are all within an arms reach.

[bent]

I can see why I would like to create a vacuum air pump at the ceiling level, as opposed to through the ceiling with box walls right up to through the roof b/c not only can I exhaust the hot inside environment air out, but also force the hot attic air out. I do not want to draw hot(ter) attic ari in though. I know I will be opening windows. But as far as creating the vacuum pump action at the ceiling level goes, I am worried about having too much open ventilation, as opossed to not enough, especially since I will see sunlight through the vented soffit on the blades of the fan!

[bent]

This whole house fan method relies on cooler outdoor air at night and open windows. When it gets really hot, the main level does get air-conditioning, and the basement is naturally cooler. If possible I want to have a design that will allow me to benefit from this fact also. There is already a ceiling fan on the same ceiling closer to the lower steps.