What temp to set new power roof vent fan.


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Old 04-14-05, 04:02 PM
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What temp to set new power roof vent fan.

I just replaced the attic roof fan. It came with a new thermostat. What temperature do I set it? The range is 70 to 120 on the dial.

Im thinking to set it at 95 or higher, cause when its 90 outside, it will sure be 120 in the attic all day.

Misc info:

Cool air enters the eaves (soffits) on a hip roof. There are 2 tiny 8" roof vents. No other heat exit points. Composite roof shingles, ya know, asphalt like. I am insulating the attic to r-30 as we speak.

The attic is 600 sq feet. The fan is the smallest sold at Home Depot and says it works for up to 2400 sq ft attics.
 
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Old 04-28-05, 06:59 AM
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Most of the time I set them at 100 on and 95 off.
Attic sq ft X 0.7=== CFM of the fan you need.

ED
 
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Old 04-28-05, 11:16 AM
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Thanks for the feedback. Just the other day, I saw the instructions recommend 105 for who knows what. lol
 
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Old 04-28-05, 12:26 PM
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You have to like play with it. Thats like they say a tile roof will save you on AC HA HA, Had one home here with tile roof put a fan in it, You know the fan didnt come on till about 1 or 2 hours later than the one in the shingle roof did.But then it would run about 2 hours longer at night from the heat still in the tile.

ED
 
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Old 05-16-05, 05:05 PM
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My old house was not insulated too well. I installed an attic fan and set it turn on at a lower temperature (about 90) and it made a slightly noticable difference in keeping the house cool. Now that I live in a more modern, better insulated home I do not notice attic fans effect on the temp in the house at all so now it comes down to saving the shingles, so I have them set to a higher temp (about 110).
 
 

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