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How hot should your attic get?

Discussion in 'Chit-Chat' started by mabrodis, Aug 1, 2005.

  1. mabrodis

    mabrodis

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    Doing some wiring yesterday, new ceiling fan going into our guest room, and whole-house fan, so I was up in the attic. I've been up there before, it's always mother-hot up there, and yesterday was no different. I climb up there, can't really standup, have to be careful where I walk, etc, and man is it hot, started sweating instantly. I came back down and the 90-degree house feels cold compared to the attic. I was guessing it was probably 125 degrees up there, so I went and got my thermacouple (pretty accurate temp measuring thing)...

    142 freaking degrees! No wonder I was covered in sweat, couldn't focus and doused the insulation with piles of sweat. I knew it felt sauna-ish...wow!

    So how hot is too hot for an attic. We have probably 10 vents in the attic, atleast 4-5 ones up through the shingles, and then the under-eve ones around the house. Vented far better than many homes I see, but that seems a bit excessive, and trying to walk/crawl while grabbing trusses that are 142 degrees kinda sucks.

    Man that was hot, it was wierd, it actually affected your thinking, like I had to stop and think about what I was doing, actually focus on something to push off the effect of the heat...
     
  2. Liam

    Liam

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    Do you have any windows? Maybe install a blower fan aka attic fan..
     
  3. swank60

    swank60

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    I had to do a photo shoot in my attic in Dec or Jan - it was mild outside, maybe in the 40-50 degree range, but in the attic it was above 110+ degrees, easy (we were running about 1000 watts of lighting, too). It does bake your brain and make it hard to think. Had a friend helping me and we both stopped when we were almost done beacuse we couldn't think right - it was almost like the crap that goes through your head when you have a high fever.

    I can't imagine what the heat is like in my attic in the summer. I'd bet on a really hot day it's nearly 200 degrees.

    Be careful doing that crap...
     
  4. Jman

    Jman

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    Ahh, but it's a dry heat. . . . .


    Saunas are neat--just dive into the pool afterward. Refreshing!
     
  5. Capt. Jim

    Capt. Jim

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    Those temps are not uncommon here in Florida attics. Be careful if you install a T-stat controlled fan driven attic ventilator. I have seen many that have stopped working in off-season due to corrosion/nests/binding rotors. These get real hot the next time they activate creating a fire hazard. I have seen several aluminum fan motor housings that have literally melted.

    Try to do your attic work early in the AM after it has cooled during the night.

    Passive is the best way to keep youir attic cool. (No fans) More than anything, be sure to have adequate insulation installed for your ceilings.

    On a final note, too cool of an attic can result in AC ducts condensing excessive moisture causing a potential mold problem.
     
  6. mabrodis

    mabrodis

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    I don't doubt it, this wasn't even close to a 'hot' day either..

    Be careful? You mean make sure my wiring is ok...and not tighten a wire clamp too tight so it shorts the switched leg with ground and when you flip on the switch it blows the breaker? :doh:

    So yeah, that was another trip in the attic (cooler 2nd time though) with my ohm-meter to figure out WTF was wrong...rewired parts of it AGAIN..but on the bright side I found some electrical tape and a kitchen knife I had left up there from when I ran running our ethernet cables up there.

    :D
     
  7. mabrodis

    mabrodis

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    Good point on the fan filling up with critters and such, we have really no bugs of any sort, but bird nests are around at times, so good call.

    Yeah we have several of those passive vents, hot air would just go out I guess, but they aren't at the peak of the roof, so not sure how well they would work.

    Well since we have no a/c, and nothing will ever mold here...ever...don't have to worry about that...oh and there is no duct work of any sort in the attic.. :)

    :D
     
  8. TJDIV

    TJDIV Back in The U.P.

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    FUN.


    I reinsulated my attic yesterday. 30 Bags of Blow In. Talk about s*** work. My thermostat and ambient temp numbers haven't matched up all summer. Last power bill was $360!!!


    If the insulation and attic fan don't work, I'm going to install 2 or 3 more attic fans. Just replaced our outside 2 ton with a 2.5 ton and the air handler is fine......



    Ih8a/c_and_heat.
     
  9. archie

    archie

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    I found the best time to work in the attic is in winter/fall when you can cover yourself up with old sweatshirt to keep the fiberglass insulation from sticking to your body. Wearing a face mask/respirator also keeps it outta your lungs.
     
  10. srafj40

    srafj40

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    Here in Arizona Pulte is building with a blown cellulose (sp.) in the trusses, held up by batting. Not blown over the ceiling. I was up this weekend finnishing a speaker job. Max temp 96.
     
  11. mabrodis

    mabrodis

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    The insulation in our attic is blown in, but not sure what type, it's white, looks/feels like cotton, not itchy at all, does make me cough a bit up there, but that could just be dust or me breathing my own sweat, who knows.
     
  12. madoc1

    madoc1

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    capt. , tou sound like th expert. i have two powered roof fans that were crapped out when i bought this place two years ago(inspector missed this) i have since turned off the power to them because of the concerns tou mentioned.

    anyway, these have 14inch dia. risers in the roof (i am sure cause the squirrels got in last winter and had crawl up there and straighten out the vent around the edge). most wind powered turbines are 12 inches. do they make a 14 inch dia. turbine vent?



    jim
     
  13. 97 FZJ80

    97 FZJ80

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    You can replace the motor on the power vents without removing the dome. While you're at it, put in the metal mesh shield around the opening to prevent the critters from getting in next time.
     
  14. Capt. Jim

    Capt. Jim

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    The standard roof turbines are smaller than the power vents. The will stiill work passively allowing heat to escape without the fans running, just at a slower rate. I find myself in attics frequently and in most cases, the power vents need some sort of service, if not being completely inoperative.

    On a good note, the base flanges of many roof turbines may be large enough to cover the hole left by the power vent.
     
  15. Spook50

    Spook50 Get ready

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    Yeah, so's an oven.
     
  16. Gold Finger

    Gold Finger

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    Just put 2 inches of rigid urethane foam insulation between the rafters under the slate and it will stop being an issue.

     
  17. Outback

    Outback

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    I was told my my HVAC guy that about 20 deg. over outside temp is starting to get bad and you should llook at why. Haven't checked mine this year -- too damn hot up there :D

    He doesn't like the electric fans, says they cost more than they are worth. Passive hip vents work best.

    Jody.
     
  18. RedGreen

    RedGreen

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    This is a very complicated question and I've been thinking about it a lot lately. There are new thoughts emerging about insulating the roof layer and sealing the attic instead of insulating the ceiling and venting the attic. Benefits would be that your ductwork would be in more of a conditioned space and you'd keep all that moist hot air (esp. in FL) out of the structure. The disadvantage is you may need a little thicker insulation. This is done all the time on commercial buildings but slowly making its way to residential buildings.

    If you're truely interested in figuring out the temp in your attic, read this:
    http://www.fsec.ucf.edu/bldg/pubs/stratified/
    Or just put a thermometer in the attic.

    I'm strange as I actually find this junk interesting.
     
  19. Jman

    Jman

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    All I know is that, when summer comes around, and it's 95 degrees out (and probably 130 in the attic) there are no longer any mice living in my 130 year old house.
     
  20. my64fj40

    my64fj40

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    When we had a new roof put on our house, we had this stuff called ridge vent put in. It runs on top of the roof and its elevated about 1 inch up. This made the attic temp drop about 20 degrees.

    Also, my dad owns and runs an A/C comp. and when it's that hot in your attic, and you have A/C, that's bad. It's even worse when your inside unit is located in the attic.

    PS. Yall don't know what real heat is. Have you ever worked all summer helping your dad remove old duct and putting new duct in. And trust me, it never cools down in Corpus Christi, Texas. Never.