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  1. #1
    Join Date
    Oct 2005
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    52

    Question

    Hi everybody, this is an awesome forum for a research junkie like me. I have spent the last several weeks reading a lot of threads, before posting something I haven't found an answer too. I sure have learned a lot & had some good questions for contractors when getting an estimate.
    I live in Northern Ohio, about an hour South of Cleveland & am looking at purchasing a Lennox G61MPV-60D-135 furnace with a XP19 or XP13 heat pump. Since we only use a/c for about 3 months or so here, is it nessesary for a 2 stage h/p? I'm not really worried about a bit of a temp swing with a single stage unit. I'm also reading on here that a high SEER rating is not nessesary either for being this far North. The contractor is coming tomorrow to do the Manual J (the only one willing to) & I was wondering what your opinions are.

    Again, thanks for providing such a good site!
    Keith

  2. #2
    Join Date
    May 2000
    Location
    Indianapolis, IN, USA
    Posts
    34,151
    I think 2 stage super SEER units are overkill in cooler states like Ohio. I'm right next door. Often the high SEER doesn't mean high HSPF which is your winter efficiency. I'd look towards 12-13 SEER max for this area. You won't have comfort issues, just don't oversize the furnace or the heat pump. Make sure your dealer uses a dual fuel control that gives you 3 stages of heat if you get a 2 stage gas backup. More comfort than letting the timer in the furnace stage the fire.

  3. #3
    Join Date
    Nov 2000
    Location
    Eastern PA
    Posts
    68,944
    Well, depends on your terminology. A heat pump system is by nature "two stage" in that it operates strictly as a heat pump in the first stage and with auxiliary electric heaters or uses a fossil fuel furnace instead of for the second stage.

    With a fossil fuel, dual fuel set up, you may or may not require a two stage function depending on whether or not you are utilizing an outdoor themostat.

    If you are referring to a heat pump that itself operates on two stages, a high and a low stage, then no, it is not required. A single stage heat pump is perfectly fine when used with a two stage gas furnace.
    Government is a disease...
    ...masquerading as its own cure…
    Ecclesiastes 10:2 NIV


  4. #4
    Join Date
    Oct 2005
    Posts
    52

    Smile

    Thanks for the reply BaldLoonie. From some other posts on here, I kind of got that impression. I'll look at the HSPF numbers then as a better comparison. One question - is the dual fuel control a seperate unit from the thermostat? I'm also watching the thread on the Lennox Signiture stat vs a Vision Pro.

  5. #5
    Join Date
    Oct 2005
    Posts
    52
    Originally posted by RoBoTeq
    Well, depends on your terminology. A heat pump system is by nature "two stage" in that it operates strictly as a heat pump in the first stage and with auxiliary electric heaters or uses a fossil fuel furnace instead of for the second stage.

    With a fossil fuel, dual fuel set up, you may or may not require a two stage function depending on whether or not you are utilizing an outdoor themostat.

    If you are referring to a heat pump that itself operates on two stages, a high and a low stage, then no, it is not required. A single stage heat pump is perfectly fine when used with a two stage gas furnace.
    I'm going dual fuel with a gas furnace. I was referring to a 2 stage heat pump with low/high operation.

  6. #6
    Join Date
    Oct 2005
    Posts
    96
    Baldloonie..........Is a two stage heat pump overkill in Kansas City???

  7. #7
    Join Date
    Nov 2000
    Location
    Eastern PA
    Posts
    68,944
    I don't see where a two stage heat pump is overkill. They are designed for added comfort, not capacity or efficiency.
    Government is a disease...
    ...masquerading as its own cure…
    Ecclesiastes 10:2 NIV


  8. #8
    Join Date
    Oct 2005
    Posts
    96
    So a two stage compressor doesn't buy me any efficiency? I was assuming if I ran at 2.5 tons on a 4 ton compressor that I would be gaining efficiency during low load conditions? Is the comfort obtained using a two stage compressor worth the money?

  9. #9
    Join Date
    May 2000
    Location
    Indianapolis, IN, USA
    Posts
    34,151
    The real high SEER stuff is 2 stage. Either Trane's dual comp or the unloading scroll others use. So yes, buying one of them buys you SEER. In much of the country with mild summers and good electric rates, you won't get your money back in energy savings. OK, so they could deliver some extra comfort. But most people are very happy with a properly sized single stage A/C. If humidity control is an issue, get a variable speed blower with dehumidify on demand. Even in steamy weather, my house stays good on humidity with the slow ramp up of the blower, I'm not using a humidistat to slow the blower. So what would I get for spending ooodles more for 2 stage cooling? I sure don't see it and I buy for under wholesale if I want one! So hard to say what the definition of overkill is A lot of money for little benefit? But if budget is no object...

    Many homes have moisture issues in mild weather when there isn't call for cooling. OK, a 2 stage unit running more on low could help but many have a high sensible on low which doesn't suck a lot of moisture. Better off would be a large dehumidifier like a Thermastor or Aprilaire. If your house is on a basement, put one of them down there and the whole house will immediately dry out.

    For Mopar, the Vision Pro thermostat and others will do your dual fuel controlling. The Vision Pro will not do 2 stage gas backup. White-Rodgers has a model that does, I looked it up for another thread, I think it was the 1F95-391.


  10. #10
    Join Date
    Apr 2004
    Location
    Midwest
    Posts
    2,683
    It is possible I live in the same town as mopar guy, and I am now using a two stage heat pump and dual fuel. I actually have 4 stages of heat, best investment I have ever made.
    Live each day like it is your last, for one day you will be right!

  11. #11
    Join Date
    May 2004
    Location
    Rapid City, SD
    Posts
    7,415
    You do get more SEER with a 2 stage... here's the fine print though. Of course the 2 stage units are always the higher SEER units (16 and 18).

    But I was also told that the SEER rating for a 16 SEER heat pump running on the low stage could be 17 or 18 SEER, while running on hi stage it could be 14 or 15. They average the numbers to get the SEER rating they stamp on the plate. I didn't get exact numbers on how much the SEER rating differs on low an high, I was told it's not a lot, but it is definately different.

  12. #12
    Join Date
    Oct 2005
    Posts
    96
    HVAC r us 2 - Which stat are you using to get 4 stages. Is it the White Rogers Stat that was mentioned earlier in this thread?

  13. #13
    Join Date
    Apr 2004
    Posts
    7,680
    What city.... I grew up in Wooster.

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