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  1. #1
    Join Date
    Sep 2005
    Location
    Fairfield, CA. 94533
    Posts
    7
    I am very much a nubee; I am on system overload so any advice is appreciated.
    We need to change our 22 year old gas furnace and air conditioner. We have had three estimates ranging from 42.00 to 7,000.00. All happen to use Trane (one actually is American Standard but I understand it's the same)

    Unsure of make of our existing units but if I remember right, I think Frazier-Johnson (or something like that) All three estimate the AC to be between 6.5 and 7.5 SEER and the furnace is 60K BTU. Unsure of tonnage but am guessing well under 2 ton. When the furnace was working at its best, it still was not forcing much air to the furthest three rooms.

    #1 uses Am St and says I need to increase the BTU to 80K and that an 11 SEER unit is all we need (3 ton)

    #2 says 80 BTU also, recommends 2 stage and a 11.5 SEER unit for AC (3 ton)

    #3 says 60 BTU and the return air ducting needs to be sealed a bit. 13 SEER AC with the new gas but if I wished, 12 SEER with current gas but recommend the 13.
    Difference of 900.00 between the 12 and 13 SEER AC's

    All three seeemed knowledgeable and are reputable. The latter two seemed more professional however #1 is self employed and I am not worried because he does not drive a shinny new truck or pressed uniforms. He appears to have our needs at interest

    Sorry for rambling on, as you can tell we are very confused. Any input is appreciated.

  2. #2
    Originally posted by steff3
    He appears to have our needs at interest
    Have any of them done a load calc?

    Is the old unit running 100% of the time and NOT heating your home?

    If not, and there are just temperature variances, there is NO reason to upsize the furnace!!!!

    Any one doing so IS NOT looking out for your best interest!

    BTW, the new equipment is more efficient than the old, so right off the bat a new 60 is putting more heat in your home than the old one is.

  3. #3
    Join Date
    Nov 2004
    Location
    SW FL
    Posts
    6,273

    Exclamation Variable Speed Quiet

    Originally posted by steff3


    #3 says 60 BTU and the return air ducting needs to be sealed a bit. 13 SEER AC with the new gas but if I wished, 12 SEER with current gas but recommend the 13.

    All three seeemed knowledgeable and are reputable.
    Buy the one that is sized properly to handle humidity.
    Location ___ ?
    Designer Dan
    It's Not Rocket Science, But It is SCIENCE with "Some Art". ___ ___ K EEP I T S IMPLE & S INCERE

    Define the Building Envelope and Perform a Detailed Load Calc: It's ALL About Windows and Make-up Air Requirements. Know Your Equipment Capabilities

  4. #4
    Join Date
    Jan 2004
    Location
    Lancaster PA
    Posts
    67,907
    Look up at the top of the screen, you'll see a red tab, use it and do your own load calc.

    Then see if it close to what your contractors are saying. If not, show it too all 3, and the one/ones that balk about it, are the ones you don't want.

    Might not be the furnace size, could just be the evap coil is dirty, and that is why you have poor air flow. A 60, and an 80,000 often have the same size blower.
    Contractor locator map

    How-to-apply-for-Professional

    How many times must one fix something before it is fixed?

  5. #5
    Join Date
    May 2000
    Location
    Indianapolis, IN, USA
    Posts
    34,083
    Your profile doesn't say where you are, that would help us address which SEER is right.

    The A-S/Trane models may say 11 in them but unless a very pricey coil is used plus a hard start kit on the A/C, you are getting 10 SEER. In many parts of the country, that's just fine.

  6. #6
    Join Date
    Sep 2005
    Location
    Fairfield, CA. 94533
    Posts
    7
    Sorry, I have updated my profile. We are in Northern CA. Between Sacramento and the SF/Oakland Bay Area.

    The Trane quotes are for XR11 12, and 13 series.

    The old furnace would run quite a bit and not heat the house evenly. Would cycle off before it would reach temp setting of between 74 and 76 degrees. I would have to turn the thermostat(new) up 2 to 4 degrees higher than the desired temp just to get the room close to what we wanted, causing the furnace to run longer.

    I know that #2 actually went outside and measured the front and side of the house to get sg ft (even though I had told him 1485). The other two took my word for it and all three would take a few minutes to do some figuring on paper. I don't know if that is how they do the calc or not.

    #3 was the only one who pulled the front cover off the furnace to check the fan, return air, etc.

    Sorry, but I am not very technical in this area at all.

    Thanks for all your replies.


  7. #7
    Join Date
    Jan 2005
    Posts
    340
    Originally posted by steff3
    ... #2 actually went outside and measured the front and side of the house to get sg ft (even though I had told him 1485). The other two took my word for it and all three would take a few minutes to do some figuring on paper. I don't know if that is how they do the calc or not.
    It's not. To size your system properly they need to know the orientation of the home, the number and size of windows, the amount of insulation in walls and ceiling, and more.

    Find a contractor who will do a true heat gain / heat loss calculation instead of guessing. Besides, AFAIK this is required by law in CA in order to get a permit.

    http://www.proctoreng.com/articles/bigger.html


  8. #8
    Join Date
    Sep 2005
    Location
    Fairfield, CA. 94533
    Posts
    7
    Wow! I had no idea it was that technical. Thank you for enlightening me.

  9. #9
    Join Date
    Sep 2005
    Location
    Fairfield, CA. 94533
    Posts
    7
    I thought I saw something on the Trane "B" series as opposed the their"R" series and to stay away from th B stuff.

    Anyone have advice? One of the contractors I am considering wants to sell the B series.

    Thanks

  10. #10
    Originally posted by jultzya
    Is the old unit running 100% of the time and NOT heating your home?

  11. #11
    Join Date
    Sep 2005
    Location
    Fairfield, CA. 94533
    Posts
    7
    The old unit runs most of the time, cuts out prior to set point, then cuts back in in a few munutes. This repeats on & on. I have to turn up the set point in order to keep the unit running enough to heat the house.

  12. #12
    Join Date
    Mar 2002
    Location
    Concord, CA
    Posts
    2,635
    B is for builder. It's not that much more for R, at least at the wholesale level. Get the R.

    Here's the deal:

    Our climate (northern Cal) is extraordinarily forgiving. Either the 60 or 80 would probably run just fine. The biggest difference between the two would be run time. Generally speaking longer run times are better. And generally speaking a "less than real hot" air will stratify less and mix better. But ultimately either will do the job. The elitists will blast me. That's fine. I'm one of them. But they don't know our climate like I do.

    The same goes for cooling. We get away with grossly oversized air conditioners all the time because we don't have to worry about humidity. That is NOT the same thing as saying I endorse oversizing. I'm just giving you reality.

    As far as SEER goes, it will take quite a number of years to get your money back. A 12 might give you a ROI in 5 to 10 years. A 14 may never give you ROI. Our summers are just too mild compared to a lot of the country. It depends on your usage and how long you plan on living there. It depends on brand too. A Goodman 14 SEER is a LOT less expensive than a Trane 14 SEER. Those that claim quicker ROI... well – let them prove it. And FYI: The whole “heating degree days” and “cooling hours” nonsense is a ruse. If you haven’t heard those terms yet, good.

    Your biggest problem in terms of comfort as it relates to HVAC is the ducts - period, end of story. You need properly sized and balance supply ducts. And you might need to add one or more return paths to keep the bedrooms from pressurizing and knocking everything out of kilter. ANY new furnace at either BTU rating will give you the exact same problems you currently have unless you address the ducts. And did I mention? Ducts, ducts, ducts! Check my site for more.

  13. #13
    Originally posted by steff3
    The old unit runs most of the time, cuts out prior to set point, then cuts back in in a few munutes. This repeats on & on. I have to turn up the set point in order to keep the unit running enough to heat the house.
    I would want to know WHY this is.

    Is it because the ducts are not properly sized for the unit you now have? By which a larger unit will only make it worse and shorten the new equipments life.

    Or is there some other issue (dirty coil, bad fan timer, limits, restrictive filter, gas pressure, etc)?

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