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  1. #1
    Join Date
    Sep 2012
    Location
    Las Vegas
    Posts
    1

    General Question

    Hi All, I have a 20 year old Lennox 5 ton system That was installed new for me. The compressor has given up the fight according to a repair man I had look at it. I am pretty up on this stuff and I believe it is true. It has been a good unit and we are happy with Lennox. My question is what are the developments in the newer units to make them have a high seer rating? I know on my pool equipment they have made dramatic improvements in the efficiency and assume this is the same. Do they have variable speeds or larger cooling fans on the compressor? Just interested in the reason for greater efficiency. Thank you for your thoughts. I hope I am asking the right area of this forum. Ken

  2. #2
    Join Date
    Nov 2007
    Location
    connecticut
    Posts
    13
    This is the Ask Our Pro's forum. In order to post a response here, you must have verified qualifications and have been approved by the AOP Committee. You may ask a question by starting a new thread.

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    Last edited by jpsmith1cm; 09-11-2012 at 09:23 PM. Reason: non AOP member

  3. #3
    Join Date
    Sep 2008
    Location
    Western PA
    Posts
    25,411
    hapomodi

    This is the Ask Our Pro's forum. In order to post a response here, you must have verified qualifications and have been approved by the AOP Committee. You may ask a question by starting a new thread.

    You can find the rules for posting and qualifications here.

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  4. #4
    Join Date
    Dec 2007
    Posts
    4,670
    basically, the efficiency comes from larger surface area to dissipate the heat, this means larger outdoor unit and usually indoor coil.

    some do have more efficient motors, DC. fan blades are no larger, usually.

    some are multi-stage, usually 2 stage unless you get into inverter technology/units.
    The Food Stamp Program, administered by the U.S. Department of Agriculture, is proud to be distributing the greatest amount of free meals and stamps EVER.
    Meanwhile, the National Park Service, administered by the U.S. Department of the Interior, asks us to "Please Do Not Feed the Animals". Their stated reason for this policy "... the animals become dependent on handouts and will not learn to take care of themselves."
    from an excerpt by Paul Jacob in Sun City, AZ

  5. #5
    Join Date
    Apr 2012
    Location
    winnipeg
    Posts
    1,330
    xc-14 my personal favorite.... quiet and wont break the bank.....
    it was working.... played with it.... now its broke.... whats the going hourly rate for HVAC repair

  6. #6
    Join Date
    Oct 2002
    Posts
    1,248
    Not what you asked. But spend money on a tighter and adequate duct system before paying more for equipment.

    20 years ago, duct system was given very little thought. Studies, I've heard, suggests 30% of AC is lost through leaky ducts.

  7. #7
    Join Date
    Jan 2009
    Location
    Keokuk, IA
    Posts
    5,520
    Don't forget ot get a load calculation done. IF you've made any energy efficeincy improvements to your home in 20 years, you might not need a 5 ton unit. Maybe jsut a 4 ton. Smaller is better. It pulls the humidity down better (humidity removal on the new system generally is not as good as the older system because of coil size) and longer run time make ht unit more efficient. Sort of like driving short trips in your car and letting the engine cool off each time. It's also possible the systme was even oversized 20 years ago. Finally a smaller unit will use less energy on the same size ductwork, and be much, much quieter. But you need a load caluclation done to determine what ht right size is. Honestly is a 20 year old unit was keeping up even on the hottest days, a 4 ton is likely plenty. Unit lose up to 20% capacity in hot weather from dirty, bent fins on the coils and the age of the compressor.

  8. #8
    Join Date
    Jun 2005
    Location
    SW Wisconsin
    Posts
    4,894
    Quote Originally Posted by kwken View Post
    Hi All, I have a 20 year old Lennox 5 ton system That was installed new for me. The compressor has given up the fight according to a repair man I had look at it. I am pretty up on this stuff and I believe it is true. It has been a good unit and we are happy with Lennox.

    My question is what are the developments in the newer units to make them have a high seer rating? I know on my pool equipment they have made dramatic improvements in the efficiency and assume this is the same. Do they have variable speeds or larger cooling fans on the compressor? Just interested in the reason for greater efficiency. Thank you for your thoughts. I hope I am asking the right area of this forum. Ken
    One of the purposes of doing a load calc is to determine if there are areas where you can cost effectively reduce the heat-gain to go to a smaller tonnage system.

    Very few homes need a 5-Ton system, because the usually undersized duct system & filter areas plus wrong type filter, reduce the delivered Btuh at least a ton lower than the equipment's Rating.

    Power companies ought to provide free, or very low cost, Home Energy Efficiency Audits that also indicate the amount of air infiltration & duct system leakage to be addressed.

    What state do U live in - near what large city?
    What's the sf of your home & approximate sf amount of E,W, & Southern window areas...we need to get an indication of your situation...

    We need to begin to do more things right and, in the right order of sequence...

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