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  1. #1
    Join Date
    May 2005
    Posts
    22
    OK I have tries almost every thing here’s my problem:

    I live in Central Valley California where the temperature is typically 96 plus degrees throughout the late spring, summer and early fall. At time the temperature is 110.

    The AC unit works fine; it blows cool air except when it’s really hot.

    I put in some insulation (blow in) a month ago because there were parts of the house that didn’t have any insulation.

    The furnace/blower unit is located in the attic (I know that sucks). The compressor is in the backyard exposed to the Sun all day. I gave it some shade without disrupting the airflow. I was looking at the furnace/blower unit and noticed that the metal box above the unit where the main ducting is connected is not insulated (should it be?) I would think that metal box gets pretty hot in the attic and the supposedly cool air is getting pretty warm before being delivered to the house.

    My questions are should that metal box above the unit be insulated???

    How deep should the blow-in insulation be?

    Is a whole house fan a good idea to displace the hot air in the attic?

    Any advice would be appreciated.

  2. #2
    Join Date
    Jun 2003
    Location
    Florida
    Posts
    9,548
    That metal box is probably lined with insulation.The depth of the insulation is determined by what R- value you're trying to achieve. the deeper,the higher the r value. removing heat(whole house fan doesn't hurt you),but I don't know if it's cost effective.
    If everything was always done "by the book"....the book would never change.

  3. #3
    Join Date
    Jan 2005
    Location
    North Las Vegas
    Posts
    784
    No, a Whole house fan will not displace the heat in the attic and will most likley cause more problems due to pressurizing the attic space and forcing the hot air back into the home.

    If you wish to ventilate your attic see about some turbine wind vents and make sure your soffit vents are not plugged with the blown in insulation.

    Another option is a temperature control attic power vent which works off a thermostat, once again though soffit vents will have to be cleared to get decent air flow.

    Far better it is to dare mighty things, to win glorious triumphs even though checkered by failure, than to rank with those poor spirits who neither enjoy nor suffer much because they live in the gray twilight that knows neither victory nor defeat. (President Theodore Roosevelt)

  4. #4
    Join Date
    Aug 2004
    Location
    North Richland Hills, Texas
    Posts
    14,914
    Originally posted by antonyeo
    The AC unit works fine; it blows cool air except when it’s really hot.
    When was the last time you had it serviced? The above statement seems to indicate that it really is not working "fine".
    If more government is the answer, then it's a really stupid question.

  5. #5
    Join Date
    May 2005
    Posts
    22
    It was checked about a month ago; the service tech said it was fine but he had to add 4lbs of refrigerant. He could fine anything else but he said there may be a leak somewhere. What do you think about that?

  6. #6
    Join Date
    May 2005
    Posts
    22
    he could not find anything else is what I meant.

  7. #7
    Join Date
    May 2005
    Posts
    22
    My ducts are not insulated, I was thinking maybe the heat is so bad that the cool air inside the ducts is not reaching the interior. The house sits in a position that gets full sun all day until agout 7pm. (about 13 hours)The sun sets at 8:30. I'm installing a power attic vent tomorrow, perhaps I should wait????


  8. #8
    Join Date
    Jun 2003
    Location
    Florida
    Posts
    9,548
    Originally posted by antonyeo
    It was checked about a month ago; the service tech said it was fine but he had to add 4lbs of refrigerant. He could fine anything else but he said there may be a leak somewhere. What do you think about that?

    Call another company.If he added 4 lbs of freon you DEFINETLY have a leak or a huffer. Sounds like you need someone to go over it. What type of system is this? aTrane,etc.?
    If everything was always done "by the book"....the book would never change.

  9. #9
    Join Date
    Jan 2004
    Posts
    108
    When it's 110 outside, your attic is probable at least 140 degrees. For that much temperature difference, 18 to 24 inches of blow in insulation would be about right.

    Are the ducts in your attic air sealed? Any leakage, especially on the return side, will suck hot air into the system. This could be the cause of your observation that it blows cool air except when it's really hot.

  10. #10
    Join Date
    May 2005
    Posts
    22
    If I had a leak would I still have cool air blowing ? When its 90-degrees plus outside I notice a difference in the temperature the air coming from the vent is not nearly as cool.

  11. #11
    Join Date
    May 2005
    Posts
    22
    Engineer guy 18" to 24" is not nearly what I have. I have about 6" (I was listening to the Home Depot guy).

  12. #12
    Join Date
    Mar 2004
    Location
    NJ
    Posts
    1,214
    In your climate you should look into putting in a swamp cooler in addition to the airconditioning system.

  13. #13
    Join Date
    May 2005
    Posts
    22
    Engineer guy 18" to 24" is not nearly what I have. I have about 6" (I was listening to the Home Depot guy). When you said sealed I assume you meant sealed at the point it connects to the diffuser? I don't think they are sealed but they have what looks like thick zip-ties holding it in place.

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