Help! Lost & Confused
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  1. #1
    Join Date
    Nov 2005
    Posts
    6

    Confused

    Hello. As suggested we have done a heat loss calculation--as a whole house and room by room. We have a heat loss of 35,000 btuh and presently have an 80,000 btu Bord-Warner furnace that is about 23 years old. We have received 4 estimates on 3 different brands. None of the estimators offered to run a heat loss calc and based their estimates on the size of the house and present furnace. One recommended a 60,000 btu, 2 stage, variable speed blower furnace based on the fact that it would run more efficiently than the existing furnace and, therefore, could be sized smaller. Two recommended an 80,000 btu, 2 stage furnace and said that the furnace would run at the first stage most of the time. A Rheem dealer recommended a modulating furnace with a 75,000 btu maximum output. From what we have read on this forum, it doesn't seem that we need an 80,000 btu furnace, but we are confused and would appreciate your input. We are looking at a Trane XV 90, American Standard Freedom 90, and a Rheem 75,000 btu modulating furnace. What size furance should we be looking at? Which is the better and most reliable brand? Should we be looking at a 90% furnace with fewer bells and whistles? We do have vaulted ceilings in two of the rooms so we are often cold before the heat kicks back on. Thanks for any insight you can give.

  2. #2
    Join Date
    Nov 2000
    Location
    Upstate, SC
    Posts
    2,919
    True, most furnaces sold today will run more efficiently that the one you have now and should be downsized for best long term operation and service. From the information you posted, it appears you need to keep searching for a contractor rather than a brand. With all the information out there today, like this forum and others, it is beyond me why there are still contractors out there that do not at least do the basics to gain a satisfied customer. Find a contractor that will do the basic load calc and at least a basic duct renovation to make your system give you the efficiency it should. Otherwise, you'll never see the efficieny and savings you expect.

    later,
    Bobby

  3. #3
    Originally posted by teeka
    What size furance should we be looking at?
    Whatever size my load calculation program comes up with...

    Which is the better and most reliable brand?
    The one that is installed by a trained, competent tech that follows codes and the manufacture's installation instructions.

    Should we be looking at a 90% furnace with fewer bells and whistles?
    Depends on your location and your different utility rates. A HP (Heat Pump) will likely offer you greater savings than either option that you've listed.

    We do have vaulted ceilings in two of the rooms so we are often cold before the heat kicks back on.
    Properly sizing the equipment is number one. Next comes a properly laid out duct system. Then, a properly installed system that is set up by a knowledgeable tech to insure your comfort and savings.

  4. #4
    Join Date
    Nov 2005
    Posts
    6
    If we had found a reliable, trained tech that follows codes, we would have hired him last week! As for properly sizing the furnace, that is what we were hoping all of you could help with. We don't know what to believe. This has thus far been a miserable experience and it isn't getting any better.

  5. #5
    You did a load calc, using the one from the top of the page?

    What's your location? (never mind... it's in your profile ), there might be someone that can help you from here.

  6. #6
    Join Date
    Nov 2005
    Posts
    6
    Yes, we did the load calc using the program from the top of the page. It is a good program, easy to use. We are pretty confident in our calculations. Our house is 1950sf, one level. Our climate is mild with temps in the 30's for the low, and an occasional few days of temps in the teens or 20's.

  7. #7

    35,000 btu's

    If that's the heat loss, then you need one slightly larger. Mild climate ... do you have a/c ,,, that will affect the blower size over 3 ton's and most of the time your looking at 70-80,000 btu's on the heat side.

  8. #8
    Join Date
    Nov 2004
    Location
    SW FL
    Posts
    6,225

    Great Advice from jultzya

    Originally posted by jultzya
    Originally posted by teeka
    What size furance should we be looking at?
    Whatever size my load calculation program comes up with...

    [
    Should we be looking at a 90% furnace with fewer bells and whistles?
    Depends on your location and your different utility rates. A HP (Heat Pump) will likely offer you greater savings than either option that you've listed.
    35,000 BTUh heating and 30,000 BTUh cooling
    seems to be in the ball-park for a
    1,950 S.F. one-story, modern residence.

    I believe that with low electric rates,
    you should investigate a heat pump system with electric strip as AUX heat. Given the Orgeon climate, the heat pump C.O.P. may average out to > 3 and the electric strip would be little used.

    i.e. TRANE model 2TWX4036 or 2TWX4042 with
    TWE040E or comparable equipment from other mfg.
    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

  9. #9
    Join Date
    Nov 2005
    Posts
    6
    No, we do not have air conditioning. We don't want to put air in. Our house stays cool and, therefore, air cond. would be used very, very little.

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