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  1. #1

    Can my Amana HVAC unit handle MERV 11 filters?

    Upfront, I admit being pretty much a layperson when it comes to HVAC. So if what I say seems ridiculous, my apologies in advance.

    I have an Amana AMH95 Gas Furnace. 95% energy efficiency. Model number: AMH950904CX. My air intake is in the ceiling and I use 1" filters.

    From what I have seen, some filters shouldn't be used because they can restrict airflow and maybe cause problems to the unit.

    I am trying to strike a balance between a good filter that can help with airborne particles/allergies and keeping the unit running smoothly.

    I was thinking of Filtrete Micro Allergen which has a MERV rating of 1000 and a pressure drop of 0.21. http://www.iallergy.com/filtrete-air...comparison.php

    I have tried to read the spec to the HVAC, but I can't make heads or tails from it with respect to whether my HVAC can support this type of filter.

    Is MERV 11 / pressure drop of 0.21 ok for my HVAC unit? What is the maximum MERV / pressure drop that my unit can handle?

    I have attached the spec for your reference.

    Thanks.
    Attached Images Attached Images

  2. #2
    Join Date
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    Page 29 describes static pressure measurements. Your unit can handle the filter, IF the filter and duct system is designed correctly and the new filter is not a significant pressure drop. Have the system evaluated by a pro in your area.
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    ???

  3. #3
    Quote Originally Posted by cartercrew View Post
    Page 29 describes static pressure measurements. Your unit can handle the filter, IF the filter and duct system is designed correctly and the new filter is not a significant pressure drop. Have the system evaluated by a pro in your area.
    I appreciate the reply. Like I said, The system was recently checked and is running fine. It is only a 1.5 years old.

    Is 0.22 a significant pressure drop? That is what the filtrete filter says it has. And remember, I am talking about the filter in the air intake in my house ceiling -- not the filter in the HVAC itself.

  4. #4
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    May 2008
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    Missouri
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    We are not a fan of 1" pleated air filters because they usually create way too much resistance. Our recommendation would be to install a 5" "air bear" style filter system somewhere in return air. Or just use the cheaper 1" filters and simply spray them with Endust or Lemon Oil Pledge before you install them. This will increase the dust catching ability of these cheaper filters and not create a restriction to the flow of air. Without knowing what your system's installation static rating is, it's impossible to tell how much negative effect this 1" filter will have on your performance.
    Just yesterday one of our techs returned from a call where HO had installed a 1" pleated air filter causing the new furnace to operate on the limit switch continuously. Greatly reduced the efficiency with a corresponding increase in operating costs. The homeowner might have had cleaner air from the registers, just a lot more expensive, cleaner air!!

  5. #5
    Join Date
    Aug 2007
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    Quote Originally Posted by DoubleTrouble View Post
    I appreciate the reply. Like I said, The system was recently checked and is running fine. It is only a 1.5 years old.

    Is 0.22 a significant pressure drop? That is what the filtrete filter says it has. And remember, I am talking about the filter in the air intake in my house ceiling -- not the filter in the HVAC itself.
    I know you just stated that your system was just checked and is working fine, but if measurements where not taken they where only guessing. You need to have someone check the available static pressure left in your system, if there is any and if it comes out that you have 0.21 available it will work.

    This more than likely will not be the case but the only way to now is to have it measured. Your equipment was designed by the manufacturer and tested and rated at 0.5 inches wg.

  6. #6
    Quote Originally Posted by second opinion View Post
    I know you just stated that your system was just checked and is working fine, but if measurements where not taken they where only guessing. You need to have someone check the available static pressure left in your system, if there is any and if it comes out that you have 0.21 available it will work.

    This more than likely will not be the case but the only way to now is to have it measured. Your equipment was designed by the manufacturer and tested and rated at 0.5 inches wg.
    Thanks.

    Are you saying that it is more than likely that I *DO NOT* have 0.21 available static pressure?

    And how does 0.5 in wg relate to a 0.21 pressure drop?

  7. #7
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    Just Opinion, This is the Ask Our Pro's or AOP forum. In order to post responses here, you must have verified qualifications and have been approved by the AOP Committee. Please see my signature line for links to register and review the AOP Forum Rules. Thank you. Your post will now be deleted. Further infractions may result in loss of posting privileges.

  8. #8
    Join Date
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    I've not found a 1" pleated filter yet that does not require being at least twice the manufacturer's required size for a filter to keep from being harmful to the system by increasing static pressure.

    Unless you are willing to have a good 4" pleated filter system or a self contained, by-pass filter system installed that will have no affect on your HVAC equipment air flow, you should use the least obstructive 1" filter available, make certain it is sealed around the perimeter of the filter and there are absolutely no unfiltered air leaks between the filter and the blower. That means that open screw holes, connections between filter rack and unit and all ducting be absolutely sealed.

    HVAC filters are for one purpose and one purpose only; to protect the HVAC equipment. If you want to utilize the HVAC system for cleaning the air better for health reasons, have a by-pass HEPA filtration system installed.
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  9. #9
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    Greenwood Indiana (Indianapolis)
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    Smile

    It sounds like he has a "filter grille" and possibly a filter at the furnace. Goggle a "dynamic air filter that connects to power and I believe is a merv 13. I don't know the pressure drop but its probably less than the filtrete filter.

  10. #10
    Join Date
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    Quote Originally Posted by Kevin Weaver View Post
    It sounds like he has a "filter grille" and possibly a filter at the furnace. Goggle a "dynamic air filter that connects to power and I believe is a merv 13. I don't know the pressure drop but its probably less than the filtrete filter.
    I missed this;
    And remember, I am talking about the filter in the air intake in my house ceiling -- not the filter in the HVAC itself.
    If there is a filter rack at the furnace, remove the filter in ceiling grill altogether and use a least restrictive, well sealed filter in the furnace filter rack.

    Most filter grills are grossly undersized. A filter in a filter grill should be much larger then a filter in a housing attached directly to a furnace or air handler. With a filter grill, there is static resistance between the filter and the blower to overcome.
    Government is a disease...
    ...masquerading as its own cure…
    Ecclesiastes 10:2 NIV


  11. #11
    Join Date
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    Quote Originally Posted by Kevin Weaver View Post
    It sounds like he has a "filter grille" and possibly a filter at the furnace. Goggle a "dynamic air filter that connects to power and I believe is a merv 13. I don't know the pressure drop but its probably less than the filtrete filter.
    Maybe that is why it was posted as "Double Trouble"

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