Hot House


Old 08-28-02, 07:03 AM
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Join Date: Oct 2001
Location: USA
Posts: 282
Hot House

Does anyone know if a house with asbestos siding is more difficult to cool vs other exteriors?

There is blown in insulation in the attic only. Exterior walls are not insulated (70 yrs old so I am almost sure)--interior walls are textured plaster.

I have a 1 story home with lots of windows, and it seems that the house holds heat more than any house I have lived in. You
The house does not even cool off much at night, even when the outside temps drop to around 68-70 degrees.

Could this be due to the asbestos siding on the house? I have never had this before, and the asbestos siding is the only difference I can think of.
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Old 08-28-02, 10:07 AM
Join Date: Nov 2001
Location: USA
Posts: 1,873
Some materials hold heat better than others. In your case, it is probably the roof and the insulation that is causing your problem. The roof gets very warm when the sun beats down on it during the day and that heat radiates into your attic and eventually into the insulation. One of the characteristics of insulation is that it retains heat as part of its process to prohibit heat flow through it. In other words, during the winter, the insulation prohibits heat loss and as part of that the insulation holds some of that heat inside it. During the summer it does the same thing except that instead of prohibiting the heat from leaving the home, it prohibits the heat from entering the home. In either case, the insulation stores heat inside itself to prohibit heat loss/gain.

During the winter, the heat stored in the insulation to prohibit heat loss must be lower than the temperature in the home. If it is 70 in the home, inside the insulation it will be about 50 to 60 and that temperature will not radiate much heat. During the summer, the temperature in your attic might reach 165 degrees F. and the insulation might store up to 150 degrees F. inside it. The warmer an object gets, the more heat it will radiate. Also, insulation retains heat and releases it slowly, which would account why the temperature in the home does not drop with the temperature outside at night.

So the siding, in my opinion, is not really causing the problem you are experiencing. The best choice for reducing attic temperature is light colored roofing shingles. I am not telling you to go out and change your roof, but consider it if and when you have to change your roof. Make sure you have adequate ventilation in the attic and/or increase it. You should also consider turbine fans and/or power fans for the attic.

Though the attic temperature during the day in the summer will probably still be higher than the temperature outside because of the enormous radiant heat energy created by the sun, the aforementioned will dramatically reduce the amount of radiant heat energy stored in the objects in the attic.
Old 08-30-02, 06:29 AM
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Join Date: Jul 2002
Location: Oklahoma City
Posts: 661
Thumbs up 70 year old house

My house is 82 years old and when I moved in had NO vents.
Adding two turbines and cutting some cool air intakes in the "soffit" help dramatically !!
You should try for at least 1 turbine per 500-600 sq ft and 150 sq in of free intake area for each turbine.
I doubt you have ANYTHING up there now unless sombody added it after construction.
Avoid power vents, they have been proven to use more power than they save in most cases (do google seach)
Old 08-30-02, 08:10 AM
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The two biggest problems are :

! The attic. You did not say what type or how much fiber insulation you have up there. If you install a radiant barrier insulation over the top of the existing it will drop your a/c bills up to 30%. The old insulation only stops about 10% of the radiant heat and this heat heats up the cileing plaster to about 110 Degs on a 95 deg day. That 110 deg ceiling is about 20 degs hotter than a ceiling radiant heat sys. You cannot win with what you have or by adding more bulk insulation.

2 If you plan to reside the house then you can incorporate a Radiant barrier into the siding work.
If not, then you should seach for radiant barrier paints on the web. Painting the inside of exterior walls along with the radiant barrier in the ceiling will make your home much more comforable and reduce those utility bills.

If your income is limited then you can also paint the ceilings, but the best way is the combination of the two.

Thank you for considering my opinion.

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