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  1. #1
    Join Date
    Mar 2005
    Location
    Waycross, Georgia
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    33
    How do you loose efficiency of ac with dirty filter?

    If your filter is dirty it would make your blower motor pull less amperage. If your filter is dirty your pressures will be lower, will it loose efficiency because it doesn't have the same cooling capacity with a dirty filter?

  2. #2
    Join Date
    Dec 2002
    Location
    Houston,Tx.
    Posts
    15,847
    Well right off the top of my head for starters you will not be removing as much heat from your home with a dirty filter, and I think if I am not mistaken that is what an a/c is supposed to do remove heat.
    __________________________________________________ _______________________
    “Experience is a hard teacher because she gives the test first, the lesson afterwards". - Vernon Law

    "Never let success go to your head, and never let failure go to your heart". - Unknown

  3. #3
    Join Date
    Jan 2003
    Location
    Kansas City
    Posts
    1,482
    You lose overall system capacity. A motor's amp draw is reduced with a dirty filter because it is moving less air. This decreases the load presented to the indoor coil. The coil ends up doing more latent heat removal and less sensible cooling. Unfortunately the shift is not equal.

  4. #4
    Join Date
    Sep 2004
    Posts
    3,157
    coggin air
    Professional Member

    Registered: Mar 2005
    Posts: 17
    How do you loose efficiency of ac with dirty filter?



    you are a professional member? Are you an hvac engineer?

    just wondering

  5. #5
    Join Date
    May 2005
    Location
    Western Kansas
    Posts
    267
    I once told a customer/buddy this after he asked a similar question and I changed his packed filter....."take a towel and duct tape it around your mouth and nose see how it's a little tougher to breath, then add another towel to simulate restriction..the same thing happens to your a/c and an unchanged filter, you're both starved for air"...btw, he takes much better care of his system since I talked to him in "laymans" terms. He's not a hillbilly nor stupid, just ignorant of how air conditioners work...it's amazing how many there are out there just like him...(they pay my bills, gotta love'em)

  6. #6
    Join Date
    Dec 2002
    Location
    Houston,Tx.
    Posts
    15,847
    Originally posted by ct2
    coggin air
    Professional Member

    Registered: Mar 2005
    Posts: 17
    How do you loose efficiency of ac with dirty filter?



    you are a professional member? Are you an hvac engineer?

    just wondering
    __________________________________________________ _______________________
    “Experience is a hard teacher because she gives the test first, the lesson afterwards". - Vernon Law

    "Never let success go to your head, and never let failure go to your heart". - Unknown

  7. #7
    Join Date
    Sep 2002
    Location
    South Dakota
    Posts
    6,579


    Actually, as the filter gets dirtier there is something in the system that becomes MORE efficient. Do you know what it is?


  8. #8
    Join Date
    Dec 2004
    Posts
    200
    Yea the filter!

  9. #9
    Join Date
    May 2005
    Posts
    996
    well, lets see:

    a dirty filter restricts air flow. when the air slows down, more heat and water are removed. now, because the coil is designed to do X amount of heat at X cfm while running at a temp of X. you lower cfm, you lower demand on the coil and the coil will become colder. as it gets colder and colder, it removes more and more water. once the coil reaches about 32* F and below, you get:






    <for bigger pic click below>
    http://img242.imageshack.us/img242/5474/icee13qe.th.jpg


  10. #10
    Join Date
    May 2005
    Posts
    996
    THATS RIGHT! ICE. YOUR COIL FREEZES UP! HOME OWNERS:

    CHANGE THE D@MN FILTER!!!!!!!!!!!!!!!

  11. #11
    Join Date
    Dec 2002
    Location
    in a house, Appomattox, Va.
    Posts
    3,252
    With a well designed system you would be trying to hit the sweet spot where several performance curves hit their max. Airflow being off would shift you down the slope, so to speak.

    For cars a certain gear and speed will give best performance because the curves hit the optimun at a certain point.Hitting that area gives best mpg, even though the speed may be 35 mpg.

    blowers, compressors and othewr components have performance curves,too. An undercharge charge on a system by 5%, say, could increase capacity 8%, but power consumption 10%. There are figures out there for charges being off, can't recall the exact values, but txvs tolerate off charges better than fixed metering devices.
    Col 3:23


    questions asked, answers received, ignorance abated

  12. #12
    Join Date
    May 2005
    Posts
    996
    BUT YOU STILL GET THE ICE!

  13. #13
    Join Date
    Aug 2002
    Location
    Office and warehouse in both Crystal River & New Port Richey ,FL
    Posts
    18,836
    Originally posted by coggin air
    How do you loose efficiency of ac with dirty filter?

    If your filter is dirty it would make your blower motor pull less amperage. If your filter is dirty your pressures will be lower, will it loose efficiency because it doesn't have the same cooling capacity with a dirty filter?


    Yes because it loses cooling capacity.Take a look at the mfrs. detailed cooling capacity.Say a 3 ton with 1200 cfm and then with a 100 cfm,sensible is reduced.

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