Attic fan installation


Old 03-24-05, 10:41 AM
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Attic fan installation

When you guys install new attic fans, where do you leave the thermostats initially? My site super said ~ 90, however mine was at ~ 115 when I checked.

Also do you usually install pilot switches before the fans?

Sorry if the first question is kinda off topic.

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Old 03-24-05, 10:46 AM
Join Date: Sep 2000
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Depends on where you live. In New Jersey, you can set it lower than in Phoenix. In addition to the thermostat, I'd put it on a switch accessible from below too so that you can shut it off when you don't need it or when it annoys you because it's running 24x7. At any rate, I'd start the thermostat off at a pretty high setting, maybe around 110-120. If you set it at 90, it probably will run 24x7 in the summer.

I don't really like these things much. I think they often consume more energy than they save.
Old 03-24-05, 11:43 AM
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Thanks John, that makes comon sense.

Would you happen to know approx what the amperage of the fans usually are, just a rough guess? I haven't heard mine (too cold to trigger), but your comment about a switch accessable makes me think. My switch is up inside the attic, and I don't have the room for an access ladder, just a scuttle port door made of drywall. I do my kid playing on a jungle gym / monkey bars impression to get up there.

Well maybe the fan will extend the roof life a tad.

Its 14/3 running to my attic light and fan, so I should be able to put a duplex shape double switch in to controll either the light or the fan from the bedroom closet? Do they make a piot double switch?, I could always add an old work box, but the closet wall it shelved and the space is tight.
Old 03-24-05, 12:23 PM
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Join Date: Aug 2002
Location: Mountain Williams Missouri
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Most here are on 110o off at 95o. Mine in summer comes on about 10am and runs to about 11pm with shingles. Had a home with tile roof same thing but it came on at about 11 am and ran till 1 or 2 am. You dont say what fan you have there . But to vent up to 2285sq ft is a 1/5HP and draws 8.0 amps. for 1500sq ft a 1/15 and it draws 3.6 amps.

Old 03-24-05, 12:42 PM
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Ed, great additional info, thanks. I can't see the fan too well, it is high up, and I would need a ladder or something better to climb. I can just reach the thermostat which is about a foot or so away from the fan connected by what looks like BX cable.

The house is about 3300 sq.ft. (So the attic would be about 1500-1600 sq.ft.) It is on a 14 gauge run, so I may expect some lights dimming in my master bedroom where it is fed from if it is a 8 amp. I was crossing my fingers it wouldn't be higher than 12 amps b/c I have outlets and recessed lights on that branch.

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