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  1. #1
    Join Date
    Oct 2006
    Posts
    30

    Confused Help me to choose please!!!

    Hi all.

    I am trying to replacing a main floor (2 stories house) unit to 13 SEER or 15 SEER unit with Furnace after the existing unit is out of order.

    Please help me to choose the system options


    Option# 1 Lennox 13ACX-042-230, Coil CX34-43C-6F, and Furnace ML180UH90E60C

    #2 Lennox XC14-042-230, Coil CX34-43B-6F, and ML180UH090E48B

    #3 Lennox XC14-042-230, Coli CX34-44/48b B-6F, SL280UH090V48B

    #4 Carrier 24ACC969A003, Coil CNPVT4821ATA, and 58PHA090-1-16

    #5 Carrier 24ANB636A003, Coil C36A17C539W, and 58CVA090-1-16

    I know that I have too much choice to choose.

    Two brands with 1 Stage or Variable Speed.....

    As i am not a pro, and am not sure that real life saving differences on SEER.
    I am in 30519, GA & Main floor size is around 2200 to 2300 SQ. Ft. facing East and livingroom facing West. I have been told that I need to have 3.5 ton or 4 ton unit.
    And 2nd floor unit is working OK (2.5 ton), so I will not change it.
    I will stay in my house over 6 years from now.

    Any advice will be appreciate.


    thanks,


    Don

  2. #2
    Join Date
    Jul 2004
    Location
    Massachusetts
    Posts
    6,837
    The SEER rating is the number of Btu's of cooling capacity for each 1-Watt of electricity purchased or X 1,000, the number of Btu's per kilo-Watt. Such as 13-SEER = 13,000 Btu's per kW purchased. 14-SEER = 14,000 Btu's/kW.

    First order of business is to be sure the quotes are not from companies cutting corners. No Manual 'J' load analysis with printable results = cutting corners. Any good company will require that they do their own Manual 'J'. It is generally considered legitimate for them to quote the job and NOT divulge the actual equipment size until you've signed an agreement due to the human nature of accidentally disclosing the work of one company to the benefit of another.

    Once you're sure they've done their work without cutting corners up front, then the rest is more comfort than anything. Multi-stage does a better job of maintaining temperatures where outdoor conditions vary from the extreme and they do a better job of dehumidifying where maximum capacity isn't needed daily. Variable speed air handlers and modulating heat pumps are all about improved comfort and lowered energy bills. Duct sizing is of the utmost importance in selecting variable speed products. Again, if the company cuts corners and gambles with your money, the results may be disappointing.
    If YOU want change, YOU have to first change.

    If you are waiting for the 'other guy' to change first, just remember, you're the 'other guy's' other guy. To continue to expect real change when you keep acting the same way as always, is folly. Won't happen. Real change will only happen when a majority of the people change the way they vote!

  3. #3
    Join Date
    Oct 2006
    Posts
    30
    Thanks for quick advice. "Skippedover"

    I had asked to all pro's for Manual "J" when they quoted me, but none of them clearly answer or reply me. However, they told me that "according to their extensive experiences in the field, I need to have 3.5 ton ( all of five different pro's from 5 different companies) I was really surprised that none of them even tried to calculate manual J. I have 3 ton Gibson unit with 3.5 ton Evaporated coil. Every year, I have Freon leakage problem, and I am tired of recharing freon, and I make the decision to replace whole unit this year. Should I look for another pro who will do manual J calculation?

  4. #4
    Join Date
    Dec 2001
    Location
    Ocean Pines, MD
    Posts
    6,983

  5. #5
    Join Date
    Dec 2002
    Location
    Houston,Tx.
    Posts
    15,939
    Quote Originally Posted by kdw88 View Post
    Should I look for another pro who will do manual J calculation?
    Yes! and if you find one, please let me know I will play the lotto tonight.
    __________________________________________________ _______________________
    “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

  6. #6
    Join Date
    May 2000
    Location
    Indianapolis, IN, USA
    Posts
    34,079
    When the 3 ton was recharged, did it cool well?

    90K for the downstairs of a home in Hotlanta seems a bit big too.

  7. #7
    Join Date
    Oct 2006
    Posts
    30
    Not Really. Even if re charged Freon, my main floor has never gone below 78 in Summer.
    It is why I have been concerning about the load calculation, and in my research in the web. What I found the proper size A/C for my main floor is 3.5 ton or 4 ton, but all 5 pro's opinion in the last quotes are 3.5 ton and for Furnace size 90,000 BTU.

  8. #8
    Join Date
    Mar 2007
    Location
    tx
    Posts
    1,088
    Quote Originally Posted by BigBacardi View Post
    DUDE.... you got a duct sizing issue.....as almost 96 percent of all houses have....You should really really really consider an ecm motor.....
    I enjoy reading these forums because it always offers me a chance to learn something new. I agree that most houses have some sort of ducting problems. But please tell me, out of the things that were said on this post, what was it that lead you to tell the OP that this house had duct problems? I am curious to know, and I hope I can learn something from this.
    Bad information is worse than no information at all.

    There are three kinds of people in this world. Those who can count and those who can't!

  9. #9
    Join Date
    May 2000
    Location
    Indianapolis, IN, USA
    Posts
    34,079
    Our experience says the average duct system is undersized for what's there. So if you add upwards of 33% more capacity, you better be adding at least 33% more ductwork and registers too. A variable speed motor can give a little more strength but aren't a solution to a poor duct system.

    We get into the upper 90s with high humidity too though not near as often as you. The average 2300 sq ft 2 story home would have a 3 ton for the whole house. Since you can't cool with that size and a conditioned 2nd floor above it reducing heat gain and sharing cool air, makes me thing there's something else going on besides an undersized unit.

  10. #10
    Join Date
    Oct 2006
    Posts
    30
    Hi. "BaldLoonie"

    Thanks for remind me it which I forgot by frustration of choosing the new unit.

    I totally agreed your point. Comparing others which similar to my house size and design from my neighbors, my house has significantly less vents and returns, and placed poor locations too.

    So, I have two important questions for you. Do I have to find a pro who works for Duct work first for the new unit ? or get the system first and arrange the duct work later? What should I do ?

    One more question, should I hire the same HVAC installer for the duct work or look for another place?

    thank you,

  11. #11
    Join Date
    Dec 2002
    Location
    Houston,Tx.
    Posts
    15,939
    Quote Originally Posted by BaldLoonie View Post
    Our experience says the average duct system is undersized for what's there...
    Preach on Brother! this is why even if you get a LC performed on your home, have you really accomplished anything if the duct is still undersized? Sort of like having a nice powerful fuel efficient motor in a corvette and sticking 1/2" exhaust on it.
    __________________________________________________ _______________________
    “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

  12. #12
    Join Date
    Mar 2007
    Location
    tx
    Posts
    1,088
    What happened to "BigBacardi's" post about the duct work and the ECM motor? Did someone take it down? I was seriously wanting to know how he determined the house had duct work issues and that it needed an ECM motor. Now, the entire post is gone, and I did not get to learn how that worked.
    Bad information is worse than no information at all.

    There are three kinds of people in this world. Those who can count and those who can't!

  13. #13
    Join Date
    Sep 2008
    Location
    Western PA
    Posts
    25,559
    Quote Originally Posted by surenuff
    What happened to "BigBacardi's" post about the duct work and the ECM motor? Did someone take it down? I was seriously wanting to know how he determined the house had duct work issues and that it needed an ECM motor. Now, the entire post is gone, and I did not get to learn how that worked.
    BigBacardi isn't an authorized AOP poster.

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