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  1. #1

    Question Single or two Stage, Set or Variable Speed, 3 or 4 ton? PLEASE HELP

    We have decided to go with Lennox but have been given so much different info that it’s hard to decipher it all and don’t know who to believe!

    Basic info:
    Location - Tucson, AZ
    House built in 1978, 1660 Sq. Ft., All Electric, older dual pane windows, avg insulation - no upgrades / additions

    Replacing a very old, (maybe original with house) VERY inefficient split system. My electric bills are highest June - Sept with August sometimes being THREE TIMES what the lowest bill is (usually March).

    We are looking at the following two Lennox Systems:

    1. XP14 (single stage) / CBX27UH Up to 16.5 SEER and 9.5 HSPF

    2. XP16 (2 stage) / CBX32MV Variable speed Up to 16.5 SEER and 9.5 HSPF

    QUESTIONS:

    1. The price diff is about $ installed. Considering that they have the same ratings, is the XP16 combo worth it?

    2. If we go with the XP16 / CBX32MV will we be MORE likely to need duct work because of the increased push?

    3. We've been told that we need a 3 ton and we've been told that we need a 4 ton - both did J load Calcs - how does that happen, which do we need?


    ahhhhhhh! HELP!
    Last edited by beenthere; 06-20-2013 at 04:01 PM. Reason: Price difference

  2. #2
    Join Date
    Jan 2004
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    If you need duct work done to use a VS blower. Then you need duct work done for a standard blower also, and its probably your duct work causing some of your high cooling bill.

    If your humidity is low in your area. A single stage with a VS blower should work fine.

    As for the load calc differences. best to call each contractor up, and ask them to explain why theirs is so different then the other one.
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  3. #3
    Join Date
    Jan 2009
    Location
    Keokuk, IA
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    Quote Originally Posted by TooMuchInfo View Post
    3. We've been told that we need a 3 ton and we've been told that we need a 4 ton - both did J load Calcs - how does that happen, which do we need?


    ahhhhhhh! HELP!
    GIGO (Garbage in = garbage out). A loa calculation is only as good as the data put into it. SO if one used more conservative estiamtes for insulation, shading, or used the wring desing temeprature for your location. Then they will be off. Its' also possible that you were marginal (very clsoe to a 3 ton, but maybe just slightly short).

    If you were marginal, I'd go smaller don't use setbacks (which save little or no energy anyway) and then your ductwork won't be undersized. When you can, eventually replace windows and add any insulation. WRost case, the 3 ton falls behind just a little on the hottest days, but it will be saving you money. You can always overcool the home a little in the morning on the hottest days to reduce how far it wil fall behind.

    2 stage won't benefit you as mcuh since it's a dry hot climate. The EER (performance when it's hot, rather than a seasonal average for a typcial climate) isn;t much different between a XP16 and XP14. The 2 stage will run a little longer so temepratures might be a little more even some of the time.

  4. #4
    Join Date
    Jun 2013
    Location
    Eastern NC
    Posts
    7
    This is the Ask Our Pro's forum, and only Pro members that have been vetted by the AOPC may post advise, commentary, or ask questions of the OP here.

    You can find the rules for posting and qualifications here.

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    Last edited by beenthere; 06-21-2013 at 05:33 PM. Reason: Non Pro * member

  5. #5
    Join Date
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    Patrick Eubanks, this is the Ask Our Pro's forum, and only Pro members that have been vetted by the AOPC may post advise, commentary or ask questions of the OP here.

    You can find the rules for posting and qualifications here.

    Your post has been deleted.
    Further infractions may result in loss of posting privileges.
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  6. #6
    Join Date
    Aug 2003
    Location
    Fort Worth, TX
    Posts
    11,296
    I have a Lennox XC-16 (the straight a/c version of the XP) installed in my home, I really like the two stage operation, but I also live in humid country. For arid Tucson I would have to review two stage applications more carefully. I simply like the idea of a system that can more closely adjust its capacity to meet the load...that's an energy reducing benefit anywhere air conditioning is needed.

    The Lennox Elite series of outdoor units are very quiet. So if your old condenser is a noisy rustbucket, you'll be blown away how quiet this new stuff is.
    • Electricity makes refrigeration happen.
    • Refrigeration makes the HVAC psychrometric process happen.
    • HVAC pyschrometrics is what makes indoor human comfort happen...IF the ducts AND the building envelope cooperate.


    A building is NOT beautiful unless it is also comfortable.

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