I have a small unfinished walk-in attic in my house in NY. It shares a wall
with an upstairs bedroom as well as part of the hallway. There is a small
double-hung wooden window at the far end of the attic space that I keep
partly open for ventilation purposes. The walls and ceiling (which is the
underside of the roof) had foil-faced insulation put in between the joists
by the previous owner (for whatever reason).
I have black roofing tiles on and the inside temperature during the summer
months is quite high. Sometimes I even put a dual fan in the attic window
for a few hours (on a thermostst) to exhaust the inside air.
I was thinking of maybe putting in a roof vent or even one of those turbine
fans on the roof.
They get installed on LOTS of homes along the Gulf Coast for that very
reason, to help pull air OUT of a HOT attic. For Attics, ridge and
soffit vents seem to be a better solution to that problem,
In NY, you will need a way to wrap the turbine in the winter, and/or put
up a interior barrier to keep the cold winds out.
Agreed. I've had several homes and I can't say they worked that great
either. I won't say they didn't work but I can say it still got hot
up there. Nowadays, on the gulf coast (Texas), you see new home
construction using ridge vents and soffit vents instead of the
In alt.home.repair, <rob> wrote in message
I don't think that the spinning of the turbines provides much more cooling
than just having a hole in your roof of the same size... They probably make
a difference compared to not having any opening in the roof... The ridge and
soffit vents rely on hot air rising to reduce the amount of heat in the
attic... It worked pretty good on my last house... It was still warm up
there, but not quite a warm as a previous house that relied on a electrical
vent fan... Since the ridge vents are at the highest point in your roof,
they'll probably let more air out than some vent that is stuck halfway down
your roof face... My last house had significantly more trees around it than
the previous one did, so it's not a very good comparison...
I heard of a guy once who installed a sprinkler system on his roof to help
cool his house... It was probably most efficient when he set the water flow
such that the water would evaporate, but not necessarily drip off the house
(latent heat of vaporization), but I think he had it tied in with his
gutters so that he could recover the water and reuse it... With the calcium
in Houston water, I suspect that you would have noticeable mineral stains on
your roof within a year...
Even with RO filtered water, you will get some mineral deposits. Only
distilled water is pure enough to spray on the roof without getting
Latent heat of vaporization gives the BEST heat removal. High pressure
misters (160psi - 1000psi) are far more effective at removal of heat as
the droplets are so small that they instantly vaporize when they hit a
surface. 4 misters at 160psi with a .008 orifice will dispense about 2
gallons per hour.
If you don't understand how they work I can see how you might think that.
They work very much like a vacuum cleaner.
If you don't believe, go up in the attic and make lots of dust then go outside
I'm just saying with a free spinning roof turbine, the temperature change
that I noticed was small enough that I would not be surprised that a hole in
the roof of the same size would give about the same result... If it changes
from 150F to 140F, you're not really going to notice it while in the attic,
you're just going to say that it is FUCKIN' HOT... A power vent is probably
a bit better as long as you have sufficient soffit or gable end vents to
allow air exchange... No matter what you use, you need air exchange...
Someplace for the air to enter and someplace for it to exit...
I was only going to reply to the previous post, but I shoudl have read
the others first.
I have a very good comparison, because my house had ridge and soffitt
vents, full width and the soffitts were not just a few holes in vinyl
siding soffitts, but window screen 4 inches wide the whole width of
Still intolerable in the attic, until the roof fan went in. Then 10
degrees cooler in the 2nd fllor and maybe 20 to 40 degrees cooler in
Moderately dark brown shingles. Changed to moderately light brown
shingles a couple years ago. That might mean I use the fan less, but
it doesn't affect the temperature in my attic in the summer, except
maybe before 10AM because the fan takes care of that after the fan
Maybe so. But, if he was recovering the water with his gutters, and
he had a cistern, maybe he used mostly rain water.
I tried to buy the most expensive fan I could find, because I didn't
want to have to repair it, but in 1983 there was only about 10 dollars
difference in the ones I saw for sale. I bought it at Hechingers, a
Maryland area chain that went out of business maybe a decade ago. I
guess it would be categorized as a big box store. This was well
before Home Depot or Lowes.
I have a 700 square foot house, x 2 floors plus attic and basement.
The attic is about 7 feet 6 inches in the middle and tapers to zero at
the front and rear. The width of the house is 20 something. From
that I calculated the volume and it was smaller than the capacity of
any fan for sale, 20, 30% smaller.
I'm sure you can't get my model anymore, and the make is embossed on
the cover, which is on the roof. I have the manual, but the house is
such that I couldn't find it now. I don't think the brand matters.
Controlled by a thermostat that was included. With dark brown
shingles, on the sunniest days of the summer, went on around 10 in the
morning and off around 7PM (daylight saving time). On less sunny
days, or when the sun is lower in the sky (away from June 21), it goes
on later and off earlier.
I have a cutoff so it won't run when I want the heat. On Sunday, it
was a bit hot upstairs, and I turned off the cutoff and it started up,
around noon. The windows were all open Sunday night and it was cold
Monday(53?) so I turned the fan off Usually I don't do this on and
off bit. I turn it off in late fall when I get chilly with the
windows open and on in early spring when I turn the heat off and later
I'm too warm, and I don't give it any other thought. I don't take
hot showers and I don't cook a lot of steamy food** so there is no
need to turn it on to remove attic humidity.
**Even when I do boil water for spaghetti or something, after it
boils, I turn the electric burner down to about 6 out of "10" where it
Well, it's 22 and half years, and I'm on my 4th or 5th motor. The
first one lasted about 7 years, and I sent to the fan maker for a
replacement motor. I was probably hot while I was waiting.
The seocnd motor lasted 2 or 3 years! So the next time I went to
Electric Motor Repair and bought a replacment there. 75 or 80
dollars, as much as the whole fan had been. But I don't care about
the cost. I love the fan.
That lasted 5 or 6 years.
So either my current motor has lasted 7 years or there was another
motor I don't recall. I also think one motor lasted 9 years, which
makes the one that only lasted 2 or 3 even stranger.
Changing the motor took about 30 minutes the first time, and maybe 15
minutes thereafter. (not counting turning off and on the breaker.)
It's done from inside the attic, often just after dawn, and requires
forcing the first of three brackets away from the motor. After that
it is easy. Putting it back is easy also, even the third bracket for
Anyhow, I'm happy it started this week. I don't think that guarantees
it will last though the summer, but it might last.
The rain lands on the roof and splatters, some of it hitting the
screen of the fan. Some of that goes through the screen and lands on
the floor. But never enough to make the floor "wet". It's just the
attic, but if I kept stuff that could be damaged, I'd put a plastic
sheet under it, with newspaper on top, to determine how far the
wetness extends. After that I'd get rid of the plastic and the
newsppaer and just not put anything that could be damaged in that
circle (maybe 3 feet.)
I figure the rain might be damaging the motors, so I looked into
putting additional screening where the current screen is, but that fan
lasted a 7 years or more, so I put that on the back burner.
I also think maybe I should oil the motor every eyar, and I don't
remember for sure, but I'm pretty sure if the motor had places where
it is to be oiled, I would notice and wouldn't be wondering. I figure
it doesn't have such places and uses oil-impregnated bearings. So I
think that means oiling it won't help.
Maybe I could find a motor of the same size with ball bearings?????
I hope I remember to ask next time.
I should save the old motor, so I don't have to extract the current
one before I go to the store. I think I did last time, but I didn't
label it adequately, so I don't know which motor it is, or where it
But all in all replacing the motor is only one errand in town, during
working hours, and 70 dollars, and 15 minutes just after dawn. Every
5 years or so on average. That's really not much. In return, I get
to use my upstairs all summer with only a couple weeks of AC, if that,
in Baltimore, compared to loosing three months of use or using the AC
Agreed but a lot of people don't want them now in south Texas
(typical 95 degree summer days) because it costs money inorder to run
them (net savings less) and require eventual maintenance. I used to
have power vents and they did work but used electricity and eventually
required some maintenance too.
95/95 days are common (95 F and 95 RH), it is MISERABLE, even DANGEROUS
in attics that are not well ventilated, 120F+ and high RH. Got to get
in and out FAST and be WELL hydrated with Water, not Cola, Tea, or
Coffee when going up there to maintain a power vent.
Ridge and soffitt just eliminate the need. We all have to replace the
roof sometime, do it then. Ok, in cooler climate, a powered vent solves
the problem and cost MUCH less to buy and install.
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