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  1. #1
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    Mar 2017
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    HP Help! Demand Defrost needed for Virginia? 2 stage Copeland proven? Strip Size?

    So finally replacing a 14 y.o. 2.5 Ton single stage Lennox HP in a 1600 sq foot simple Virginia rancher and would love to hear thoughts and insights on the importance of Demand Defrost, as well as the reliability and value of the other features I'm considering since 2 stage compressor has been around awhile. The one things I'm set on is the Variable Speed Air handler - Budget/Reliability/Comfort are the 3 factors here in order and this is for an all electric, moderately insulated 1990 ranch home with very hot & humid summers and many below freezing winter nights and some days.

    I was set on what I thought would be a nice upgrade on a budget -- a 3 ton Goodman GSZC18, 2 stage compressor with variable speed Air Handler. The price is right and the warranty is great. But someone has advised me that without a doubt, I need "Demand Defrost" for my climate or I will be losing a lot of efficiency and using strip heat more than necessary. Is this true?

    So a few questions. I have read all the literature I can find about the Goodman HP's, SmartShift technology, Emerson compressors and Emersons Universal Defrost Board and I can't figure out if this is true Demand Defrost or just a more complicated set up of timers and settings.

    1. How important is Demand Defrost for cold winter climates? Is this factored into HSPF ?

    2. Does Goodman's setup have demand defrost built in already or does it have to be added on separately (if even possible) ?

    3. Is the reliability of Copelands 2 stage compressor proven and for people who have upgraded from one stage to two, is it worth it or is this just complicating the system and adding more things that can go wrong?

    4. Heat strip sizing -- yes I know the obvious about finding out what is in there now but mine is a 4 staged Lennox set up that I don't know if it is running at stage 1/2/3/4 so what I thought would be the easy answer has also turned complicated given this my current set up.

    And finally, these are the 3 systems I am considering and a 4th that was offered that I can't afford. Given my situation (Retired and on a very tight Budget) what are people's thoughts and considerations - maybe something I'm not thinking of?

    System 1 - Most similar to what I already have.
    2.5 Ton Goodman HP GSZ16 - Single stage Copeland with upgraded Variable speed air handler. 16.5 Seer.

    System 2. (+ $ over system 1)
    3 Ton Goodman GSZC18 - Two-stage Copeland with upgraded Variable speed air handler, 18.5 Seer.

    System 3. (+ $ over system 1)
    2.5 Ton Trane XR14 or 15 - One-stage Climatuff with upgraded Variable speed air handler, 14.5 Seer.

    System 4. ( + $ over system 1 - can't afford so moot)
    3 Ton Trane XR17 - 2 stage Climatuff with upgraded Variable speed air handler, 17.5 seer.


    I really appreciate all the input and let me know there are any other questions or points I haven't addressed. !!
    Last edited by beenthere; 09-08-2018 at 06:12 PM.

  2. #2
    Join Date
    Jan 2014
    Location
    New England
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    Unless things changed the smart shift is a time/temperature defrost, the compressor shuts off for a predetermined amount of time but the OD fan stays running to bring down the head pressure then after A that pretertermined time the reversing vale switches to normal heat mode.

    Shutting the compressor off reduces the swooshing sound and strain on the compressor.

    Don't see why you would positively need only demand defrost in Virginia. Nice option but not absolutely needed IMO.

  3. #3
    Join Date
    Jan 2004
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    PA
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    On demand defrost is a preferred thing. But you have had time and temp defrost for 14 years. So if your new unit doesn't have it, you won't notice. But it will cost more for winter heat than if your new unit had it. And it is not an add on option.

    HSPF does take into account time and temp, or on demand defrost.
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  4. #4
    Join Date
    Oct 2009
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    God's country - Shenandoah Valley, VA
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    Where are you located in VA?
    Bob Boan


    ​You can choose to do what you want, but you cannot choose the consequences.

  5. #5
    Join Date
    Mar 2017
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    Thread Starter
    About an hour west of RVA, Louisa county. And it makes sense that my current Lennox system is timed defrost, however I just learned that my 4 stage strip heat appears to be set up to always run at least 25% power and maybe more, which is most likely why A., I don't currently feel cold blasts of air when going into defrost mode and B., my electric bill is so high!

    So while I'm very excited to have a much more efficient system, I'm a little nervous that I'm going to be dealing with the typical HP complaints of cold air/breezes/bursts given that my system has not been working as a true HP so I'm thinking that the budget 2 stage system (#2) is probably the way to go.

  6. #6
    Join Date
    Oct 2009
    Location
    God's country - Shenandoah Valley, VA
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    I'm about an hour west, near Waynesboro. I can probably do an 18 seer Bosch modulating system for the prices you been quoted for 16 seer.

    Call me Monday if you're interested: 540-337-2866
    Bob Boan


    ​You can choose to do what you want, but you cannot choose the consequences.

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