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Thread: SEER question

  1. #1

    SEER question

    Hi -

    I am proud new owner of a a XL19i... The questsion is when you look online it states its SEER rating of up to 19.50... All of my paperwork states 17.5 SEER.

    I do relize that there are different parts that make up the system, but why is there a difference... Better yet, what could I have done differently to increase this to have a higher SEER.

    Just curious...

  2. #2
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    Probably one of the best threads on here regarding SEER ratings:
    http://www.hvac-talk.com/vbb/showthr...elling+seer%22

    Depending on your climate, a high-SEER system might not be the best option. If you want the best efficiency to get a desired temperature, crank that blower as fast as it can go (and the ductwork can handle.) If you want comfort, slowe that blower down as much as possible to make sure you're removing humidity (at the expense of efficiency.) If you use higher-end controls, you can control this based on the actual environmental temperature & humidity and get the best of both worlds. Also, if you are able to get the humidity (latent heat) down to a reasonably low level (40-45% relative humidity), you'll find that you will be comfortable at higher temperatures, which, can mean setting the thermostat higher and possibly saving more energy than you would with the air conditioner running near its SEER ratings. I've seen 10 SEER equipment, when properly installed, outperform and produce a lower energy bill than 16 SEER equipment improperly installed.

    Another article on SEER, 'though I'm not 100% sold on everything they say, but I live in swampy Florida, so humidity removal's the main use of air conditioning in my home:
    http://www.advancedenergy.org/buildi...s_bulletin.pdf

  3. #3
    I forgot to mention in the orginal post that I live in the desert - Cave Creek, AZ (just outside of Phoenix)... so humidity is not a huge factor. We do have our monsoon season in the summer where it is humid for us though... http://www.wrh.noaa.gov/psr/general/monsoon/... I am going to go through this tomorrow... thanks for your reply...

  4. #4
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    In that case... crank that blower up! Another option is to up-size the evaporator coil inside by 0.5-1.5 tons (depends on the size of the unit). It'll remove less humidity, but will drop the temperature quite well. No use removing humidity which doesn't need to be removed.

  5. #5
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    That up to 19.5 is for one size only.

    I think its the 3 ton.
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  6. #6
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    Quote Originally Posted by ducatiduke View Post
    Hi -

    I am proud new owner of a a XL19i... The questsion is when you look online it states its SEER rating of up to 19.50... All of my paperwork states 17.5 SEER.

    I do relize that there are different parts that make up the system, but why is there a difference... Better yet, what could I have done differently to increase this to have a higher SEER.

    Just curious...
    I got a copy of Trane literature titled 'Split System Cooling Product and Performance Data', it reveals what must be done to get the fabled "up to" SEER of this system. According to this you need the 2TTX9030 model condensor, TWE040E13 air handler (not a furnace), and of course the thermostatic expansion valve TXV-NB. With that you will get 34,400 total cooling BTUH, 27,800 sensible, and 19.5 SEER.

    Use a furnace with that AC and at best you will lose a full SEER point. Most combos are in the 17-18 range, still good enough to qualify for the IRS income tax credit.

    Use the 2TTZ9036 size AC and you get up to 19.00 SEER, 37,800 total capacity and 29,500 sensible. This is what they call the "3.0 ton" size but I observe it is a bit more generous than the 36,000 BTUH size one would nominally call 3-ton. Larger sizes generally get progressively lower SEER, and the XL19i is no exception. If you could identify your model of coil and furnace, that would make it possible to look up the claimed SEER of your combo. However this is under laboratory conditions and many common things might make anyone's AC perform worse in the actual house -- leaky ducts come first to mind.

    The 2TTZ9030 size is called 2.5 ton but it seems so generously sized that other makers might call it a 3-ton with a little hyperbole. A lot of combinations in that size result in 32,000-33,000 BTUH output. Certainly less than 6000 BTUH different between the claimed 2.5 ton and 3.0 ton sizes. Trane even rates them at the very same CFM airflow. That struck me as weird.

    Hope this helps -- Pstu

    P.S. There is a website where you can look up your 19i with various combinations, and see the ratings: http://www.aridirectory.org/
    You can fill in just a few of the fields in the search, leave the rest blank, and get a larger number of results. Then you can narrow it down to your interests.

  7. #7
    Great info....

    I went to the site and plugged info but did not find my set up...

    TUD2D120AFV52A - Furnace
    2TTZ9048B1000B - Condendser ?
    TXC065S3HPC - Indoor ?
    TCONT802AS32DA - Thermostat

  8. #8
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    Probably a spelling "error", if you don't type the match just the way the program wants. I would help you much more, except my wife has a huge amount of entertainment packed into a weekend starting just a couple hours from now. Can you wait until next week and if still necessary we can work on ARI ratings for your system, or the closest we can find?

    One thing never to forget is the importance of duct sealing and design, and how leaky they might be due to indifferent craftsmanship. The ARI number is a lab ideal, your experience may be less.

    Best of luck -- Pstu

  9. #9
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    ducatiduke

    Looks like a 17 SEER

    Ref #798213

    http://www.ceehvacdirectory.org

  10. #10
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    What is the value of the SEER rating?

    I can't help it, the more I think and read about it the more I doubt the value of the SEER rating for people living in Southern states.

    SEER is a kind of averaged efficiency rating for an unspecified location in the US. But it ain't Houston, Phoenix, Miami, Dallas, etc.

    I like the EER number better. It gives you the efficiency at a defined situation, e.g 95 F outside temperature. And I recently read an article saying that despite the availability of 'more efficient' HVAC system with climbing SEER numbers, the EER value is stuck around 12.

    Why is this important? The efficiency of a given HVAC system (cooling) goes down the more the outdoor temperature goes up. And it's steep.

    Cooling conditions in the Summer will be closer to the EER conditions than some type of average (in North Texas: 95..105 F during the day, 80 F in the middle of night).

    Cooling costs are related to the outdoor temperature squared!

    In the Summer your HVAC system has the lowest efficiency and you need most cooling.
    In Spring, Fall your HVAC system has a higher efficiency but you need less cooling.

    So for these $$$$ 16+ SEER systems in the South: I don't believe in it. They will cut your April cooling bill nicely from $80 to $50, but reduce your $500 August bill only to $400.

    Next time your in the market for a new AC system, tell the Sales guy your looking for a 15 EER system. And 'enjoy' the long explanation that follows.

    Of course, if you live in Chicago, please disregard this post.

  11. #11
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    Inverse condition logical?

    Quote Originally Posted by tpa-fl View Post
    In that case... crank that blower up! Another option is to up-size the evaporator coil inside by 0.5-1.5 tons (depends on the size of the unit). It'll remove less humidity, but will drop the temperature quite well. No use removing humidity which doesn't need to be removed.
    So... for my southern, humid climate, could I assume the inverse holds true? If
    I downsized my inside coils I would have better humidity removal, but at what cost to the units ability to cool to the desired temperature? Is this something that is considered by most installers?

  12. #12
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    Quote Originally Posted by ducatiduke View Post
    Hi -

    I am proud new owner of a a XL19i... The questsion is when you look online it states its SEER rating of up to 19.50... All of my paperwork states 17.5 SEER.

    I do relize that there are different parts that make up the system, but why is there a difference... Better yet, what could I have done differently to increase this to have a higher SEER.

    Just curious...

    I would not worry to much about the seer rating figure your eer rating and then see what you have, but be sitting down when you figure it.
    Last edited by Mr Bill; 05-26-2007 at 02:35 PM.
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  13. #13
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    Quote Originally Posted by lackster View Post
    So... for my southern, humid climate, could I assume the inverse holds true? If
    I downsized my inside coils I would have better humidity removal, but at what cost to the units ability to cool to the desired temperature? Is this something that is considered by most installers?
    Down try to engineer a system by swaping out different coponets for just one part of the load.

    The benifit of the higher SEER units, is that they are 2 stage units.
    A 2 stage will usually get you the humidity control your looking for.

    Is a 16 SEER that will save you 100 bucks on the hottest monthes of the year worth the money over a 13 SEER? Thats up to the individual.
    Will your electric rate go up 30% in the next 5 years?
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