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Attic fan with humidistat?

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52K views 10 replies 8 participants last post by  Tin Cup  
D
#1 ·
A buddy of mine just bought a house with mold problems, the mold contractor recomended that he get an attic fan with a thermostat as well as a humidistat. He was asking me about it, but I have never seen one with a humidistat. Is there such a creature?



Thanks, Dave
 
A
#3 · (Edited)
dkillianjr said:
A buddy of mine just bought a house with mold problems, the mold contractor recomended that he get an attic fan with a thermostat as well as a humidistat. He was asking me about it, but I have never seen one with a humidistat. Is there such a creature?



Thanks, Dave
Click to expand...
yes there certainly is Attic Aire makes one

about 4 years ago i did a 12/12 pitch cut up hip roof three dormer slate tear off and replaced with carriage house asphalt shangles. It was a PITA getting everything off and dried in with just me and another guy who was scared of heights. we tarped what we tore of on the west side and the damn tarp tore of some dormer flashing during a midnight thunderstorm and caused a bit of a leak into the guys unfinished attic. I had enough of tarps for that job we began ice and water shield the entire roof as we tore off and roofed it. His attic was unvented and with no soffits there was no practical way to vent it as the hips came to a peak. this attic had six windows in the dormers that he usually kept cracked open. when the job was done about six months later he calls to tell me his attic is dripping wet. he had never had this happen with the old slate roof obviously. and he didn't want to put any hat vents on the viewable faces of the roof from the street or ridge vents on the dormers. I recommended an attic fan on the rear face of the roof with a humidistat. it worked like a charm.
 
M
#4 ·
Yes, the humidistat works very well. I believe the manufacturer would want it wired in parallel with any other controller, such as a thermostat. Wiring it this way allows the fan to come on wether it's hot or humid, or both.
 
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#7 ·
If a homeowner has the specific need or desire to have a PAV, then I educate them on the additional benefits they will derive from the versions from Certainteed/Air Vent that containst the humidistat.

This makes the fan operational year round, especially when RH content may become excessive in the winter months, which cause moisture, frost, and furthers the breeding atmosphere for mold inhibition.

A PAV with only a thermostat is a waste of time and money. Ensure that the CFM is properly rated for the attic volume and that there are an appropriate amount of intake vents with coinciding NFVA, else the other roof exhaust vents will become intake portals, possibly allowing inclement weather to breach the attic environment.

Ed
 
D
#8 ·
Thanks guys for all the info, Like I said I have done a bunch of then with just a thermostat, but I acctually never enen knew about the ones with a humidistat. Deffinetly some good info to have for the future! I will let my buddy know, now the fun part, my buddy is trying to do all kinds of stuff to the house himself I'm gonna have to pull up a chair and watch this install:laughing:


Thanks, Dave
 
C
#9 ·
dkillianjr said:
...now the fun part, my buddy is trying to do all kinds of stuff to the house himself I'm gonna have to pull up a chair and watch this install:laughing:
Click to expand...
Borrow a web cam and broadcast it....you can get Ventrilo so we can heckle him from your/his laptop :laughing: :laughing: :jester:
 
T
#11 ·
make sure you mount the thermostat/humidistat ABOVE the fan as far as possible. if it is below, the air it draws past it will satisfy the control too quick, shut off, then kick on again, etc. etc. etc. i like to put a pigtail on mine then plug into a receptacle so the next guy can replace it easier.

I only use the power fans with dual controls for extremes. most roofs can be ventilated without power fans. extremely hight temps and extremely high humidity. how much depends on your climate and other house conditions.

Tin Cup
 
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