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Posted by SQLit on July 27, 2005, 9:50 am
> In alt.home.repair on Mon, 25 Jul 2005 12:01:09 -0700 "SQLit"
>
> >
> >> My attic gets very hot, even with 3 turbines. Although it is very hot
> >> outside (temp about 99-102), an AC service man recently said that my
attic
> >> is still hot considering that all 3 turbines are working properly.
> >>
> >> The house is mostly brick and I have vinyl siding over the wood
(veneer?).
> >>
> >> I'm wondering if the siding is preventing the attic from getting proper
> >> outside air flow. The original outside vents were removed and covered
> >when
> >> siding was installed; the siding does have some venting holes.
> >>
> >> How can you tell if the attic is getting proper ventilation??
> >
> >I live in Phoenix and the attic fan is set for 140 degrees. Ya all know
how
>
> I know you live in Phoenix, and I live in Baltimore, where it isn't so
> hot, but 140 strikes me as high. It's been 22 years, but I vaguely
> remember mine being set to 120 when I opened the box.
>
> That doesn't meant to me that my attic is never hotter than 120. I've
> thought about raising the temperature setting, but but I figure as it
> is, the fan goes on earlier, and doesn't fall behind so soon, and the
> attic stays less hot most** of the day than it would be if it turned
> on later. I figure it goes off later, when outside air is cooler, so
> the attic is left cooler when the fan goes off.
Probably a good idea for you. I just did not want the fan running 24/7 all
summer season.
I also had turbines. It was just a number that I picked. My fan was
purposely over sized but not by enough. I believe if I ever install another
fan I would be a 2X the air recommended.
> **It's not the maximum temperature of the attic that matters, imo.
> It's the average temperature. So even if it is over 120 or 140, the
> less time it over those numbers, and the lower it is at any time, the
> less heat will be absorbed by the attic floor and transmitted to the
> living space beneath. Whether there is lots of insulation or none,
> there will still be a difference.
I believe it is the thermal invasion from the attic to the conditioned areas
of the home. High or median would make little difference. That is where the
blanket of insulation come in.
> >cool it is in Phoenix this time of year. It turns on in the mornings and
> >shuts off 2-3 hours after sun down.
>
> Mine turns on iirc between 12 and 2 and off by about 10. And that's
> in 95 degree weather with a dark brown shingled roof. With hotter
> temps in Phoenix, maybe yours should go on by 8 o'clock and off 3 or 4
> hours after sundown.
What time does the outside become cooler than the inside?
Last night it was triple digits until 22:00. It was 85 F this morning
> Of course I think one doesn't want to turn it on too early. I've been
> up in the attic at dawn when it was very hot the previous day, and
> it's never hot at dawn the next morning. So I wouldn't want to turn
> the fan on at 100, I sort of think, if it was already 110 outside.
> But I don't think that could happen with a brown roof. What about a
> white or light colored roof?
>
> >I can honestly say that I have notice no difference in the attic/home
since
> >installing the fan. Other than the noise it makes.
>
> If you use AC, it will be hard to tell the difference. When I
> installed mine, I wasn't using AC and it took 10 degrees at least off
> the temp of the second floor, below the attic. It went down from 95
> or 90 to 85 or 80. Maybe as much as from 95 to 80.
>
> Without the fan, I could not bear to go upstairs even for a couple
> minutes, after I got home from work, 5:30 or later if I stopped. I
> slept in the basement and went up in the morning to shower and get
> fresh clothes. After I installed the fan, I slept in my bedroom all
> year long. (I hesitate to mention this, but I sleep naked and without
> a cover. Both before and after installing the fan. I've found that
> it can be 10 degrees hotter at the same level of comfort, if I don't
> cover myself with a sheet or anything.)
>
> >I am into passive ventilation instead of forced air for the attic.
> >
> >Call a insulation company and have another layer of insulation added and
> >forget about it.
> >
> >I had a home built in 1999 came with R-30 I bought the home in 2004 I
added
> >R-19 all over the house and R-30 over the garage. A/c bill dropped in
half
> >of the previous owner's high bills.
>
> Interesting. I"m not sure frankly what I have in the attic.
>
> Did they have R-30 in 1980?
They had it, they did not install it. 1980 where I live they would have
been using ~ R-24.
My curent house was built in 1979 and R-19 was installed. As soon as I get
the rest of the wiring and plumbing done I am calling the insulator.
snipped-=--------------------------------------
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