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  1. #1
    Join Date
    Apr 2006
    Location
    Mesquite, Texas
    Posts
    2

    Cool

    I own an 1800 Square Ft. Home in Mesquite, Texas. In an effort to make my house more heat/cool efficient, I have been installing attic fans (both in-take and out-take)to help improve air flow in the attic. Already, I have noticed a great improvement in the length of time that my system is running. In an effort to further improve the heat/cool efficiency, I am considering adding some attic insulation to the existing insulation which is now approx 13 years old. My questions are thus:

    1.) Which kind of fill type insulation is best for the North Texas area?

    2.) Should I insulate the attic space above my garage which currently has no insulation? I was not sure whether this is intentional or whether it was a cost issue when the home was built? (The garage is attached directly to the South wall of my home and serves as my woodshop.

    Thanks!

    -Mark L.

  2. #2
    Join Date
    Jun 2004
    Location
    4H: Hot, Humid Houston H.O.
    Posts
    3,304

    No insulation where no conditioning

    I believe the correct answer about your garage is, if it isn't air conditioned (or heated) then don't insulate it. You did not mention radiant barrier (RB), but I do believe it would make 1) your woodshop more comfortable, and 2) potentially reduce your AC load 8-12% if done on all your roof. You can get a pro to spray a special paint, or staple up a foil type RB near the rafters. One way is easy and expensive, the other cheap and labor intensive.

    I am a homeowner in S.Texas who grew up in N.Texas. Every new home should be built with radiant barrier in our state, and many retrofits are doable. I'm about to buy my 3rd 1000 sqft roll of foil type from a guy near you.

    Hope this helps -- Pstu

  3. #3
    Join Date
    May 2004
    Location
    Rapid City, SD
    Posts
    7,414
    I personally love that blown in insulation (the white stuff). Granted I don't do it, but it looks reasonably easy, fast and effective. Much more so than rolling that itchy crap out in a hot attic.

    Another thing to do is make sure everything is sealed tight. Make sure the gaps around windows are sealed, if possible it's a good idea to seal the holes in the top and bottom plates of the walls where wires run through too. Any leak you can stop will help, and typically this is one of the cheapest things to do to improve a house.

    I wouldn't worry about the garage unless you have some plans to heat/cool it sometime in the future.

    Is your garage sheet rocked or is it bare wood frame?
    "If you call that hard work, a koala’s life would look heroic."

  4. #4
    Join Date
    Apr 2006
    Location
    Mesquite, Texas
    Posts
    2

    Insulating Attic Space Above Garage

    Thanks for the replies!

    My garage is sheetrocked, finished and painted. It has a full sized window which really makes it nice when there is a breeze blowing or when I run my window fan.

    To be honest I was not aware of RB. What is the concept behind this? Does this prevent the attic space from being heated up by the sun?

    Thanks!

    -Mark

  5. #5
    Join Date
    Jun 2004
    Location
    4H: Hot, Humid Houston H.O.
    Posts
    3,304

    RB info

    This is a vendor site, but check out the links at left titled "About RB" and "How it Works":
    http://www.energyefficientsolutions....ucts.asp#RBInd

    You can also do a Google search and find tons of references. I recommend you pay good attention to anything from FSEC (Florida Solar Energy Center) or BSC (Lstiburek's company Building Sciences Corp.).

    In my neighborhood, virtually every new house is using RB, in the form of roof decking with the foil attached on the bottom side. RB pretty much acts as a mirror for heat, it reflects 80-98% of the energy back outward thru the roof. Your attic will be less hot and that will give you less heat gain when your AC and ductwork are located in the attic -- as most are in Texas.

    Hope this helps -- Pstu

  6. #6
    never liked powered attic fans... using electricity while trying to save it... between the ridge, gable, soffet, or cuting in a roof vent, its just a waste of power... back to original topic, insulate above garage if you want to condition it, and i prefer blown in myself, as long as you're not storing items close-by...

  7. #7
    Join Date
    Jun 2004
    Location
    4H: Hot, Humid Houston H.O.
    Posts
    3,304

    Who has all the answers? Not me, not you

    While I would expect the average house not to benefit from attic fans, the Original Poster has clearly stated he sees benefit from them. I prefer to learn from such a report rather than rain on his parade.

    Yes, all the formal research I have seen argues that attic fans in general consume more energy than they save. If someone asked me out of the blue, I would tend to recommend against attic fans, based on the formal research. We *do* know that passive eave and ridge vents will consume no energy, for what that is worth.

    But this guy might have something different about his house which causes his house to benefit when the majority do not. Already he has stated he has fans for both intake and output from the attic, that sounds like it would nullify the argument that there is negative attic pressurization causing interior air to be sucked out. This guy might be doing things right.

    Best wishes -- Pstu

  8. #8
    Join Date
    Feb 2006
    Posts
    212
    If the space is not conditioned, there's no need for insulation, but if it adjoins a conditioned space such as your house with one wall, then insulate THAT wall in between the two rooms/spaces.

    I agree with the radiant barrier suggestion. In the south, it has been documented to provide good results especially with a lower than normal existing insulation.



  9. #9
    Join Date
    Jan 2002
    Location
    Ft.Worth,Tx
    Posts
    4,584

    Re: No insulation where no conditioning

    Originally posted by pstu
    I believe the correct answer about your garage is, if it isn't air conditioned (or heated) then don't insulate it. You did not mention radiant barrier (RB), but I do believe it would make 1) your woodshop more comfortable, and 2) potentially reduce your AC load 8-12% if done on all your roof. You can get a pro to spray a special paint, or staple up a foil type RB near the rafters. One way is easy and expensive, the other cheap and labor intensive.

    I am a homeowner in S.Texas who grew up in N.Texas. Every new home should be built with radiant barrier in our state, and many retrofits are doable. I'm about to buy my 3rd 1000 sqft roll of foil type from a guy near you.

    Hope this helps -- Pstu
    Vapor barrier and insulation of garage is important. I live in Fort Worth and like to walk out into an attic when it's 100' and its not 138'+. The amount of thermal load on the home does effect your cooling cost..

    Insulate with vapor barrier and if you don't have at least R-19+ insulate some more in attic.
    "Everyday above ground, is a good day".
    "But everyday that you have made a difference in someones life, may insure you stay above ground a little longer".<aircooled>

  10. #10
    Join Date
    Feb 2003
    Location
    Huntsville,AL
    Posts
    4,125
    I use attic fan, certainly not reflective barriers -- look at my posts as to why.
    insul above gar will make it more stable in temp if door is closed -- would help keep out hot temp from roof
    harvest rainwater,make SHADE,R75/50/30= roof/wall/floor, use HVAC mastic,caulk all wall seams!

  11. #11
    Join Date
    Aug 2003
    Posts
    626
    Attic fans DO NOT save energy--period. Insulation above a non conditioned garage won't lower the temperature in the garage enough to justify the cost.

  12. #12
    Join Date
    Jun 2004
    Location
    4H: Hot, Humid Houston H.O.
    Posts
    3,304

    Fight?

    OK Starznmoon, it sounds like Uktra is calling you misinformed about your own house... to put it politely. I have seen a lot of posts where Uktra sounded right. What might it be about your house (and some other posters') which makes it respond positively to an attic fan? I would like to be open minded about this question, it appears to me it does not save energy on some homes but your might be different.

    FWIW I do believe Cem-bsee is telling the truth and pursuing the scentific method best he can with the resources available. I don't want anyone to be mistaken about that. Sounds really curious to me, but curious occurrences are not always a bad thing.

    Regards -- Pstu

  13. #13
    Join Date
    Feb 2006
    Posts
    212
    First, I will say I have no opinion either way with attic fans or not. I don't know enough for the correct answer...

    These are my readings at 72 degrees outside temperature. I have a motorized attic fan on one side of the attic and an opening on the other side for the air to come in.

    --------------------------------------------------------------------------------
    Just for the fun of it... I noted some temps and time while the exhaust fan was working today.
    3:00 PM
    Outside temp 72
    Attic temp....101... Fan turns on.

    3:13 PM
    Attic temp...95 (13 minutes and 6 degrees)

    3:28PM
    Attic temp...93

    3:38PM
    Attic temp...92 and fan shuts down.

    38 minutes to go from 101 to 92 which is 9 degrees with an outside temp of 72! That's not all that great but it DOES do the job it's intended for at least at these low temps. I'd hate to see when it gets 95 outside. lol But quite honestly, I have heard the fan cycle on and off at different times of the day in summers past, so it's not like it just runs forever when it very hot out. I must note, I did reset the stat a week ago. I will raise it a little so it doesn't run all the time.

    Just a little more info...
    After the fan shut down, the temp went up 2 degrees in 10 minutes, then another 2.5 degrees in another 10 minutes.

    4.5 degree rise in 20 minutes after shutdown.

    45-60 minutes it went back up 6 degrees.


    I didn't keep track of it's electrical consumption or the energy savings it gave at these temps. They are just numbers, so take them as just that. IMO, when it gets hotter, things won't go so smoothly.

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