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  1. #1
    Join Date
    Oct 2005
    Location
    N Metro Atlanta GA
    Posts
    70
    This is the only proposal I have to date. He is the only guy who ran Manual J. I did not think to ask for the load print out, but he ran it on a laptop in my living room & I hope he saved it. I got sidetracked when he started explaining a possible zone conversion.
    He said he had to go with the 100,000 BTU furnace to get the airflow needed for the heat pump, not for the heat load. Does this sound right?
    The house is about 1700 sq ft, 2 story, single system in Atlanta. The current A/C is 3 Tons & the 23-year old furnace is 100,000 BTU.
    I would appreciate a critique of his spec. No other bids will come in until Monday.
    Thanks in advance. This forum is a gold mine of information.

    Trane 4TWX4042*100* 3.5 Ton R-410A Heat Pump
    Trane TUD100R9V5* 100,000 BTU2 Stage Variable Speed Gas Furnace 21
    Trane RXC054S3HP* R-410A Coil 21 Wide
    7/8 x 3/8 Line set LS4-50
    Outdoor thermostat
    Honeywell Touch Screen Thermostat
    Dual Fuel Kit
    ... misc other parts ...
    Labor to install complete system (up flow level 1)

  2. #2
    Join Date
    Nov 2004
    Posts
    2,927
    Originally posted by i g norant
    He said he had to go with the 100,000 BTU furnace to get the airflow needed for the heat pump, not for the heat load. Does this sound right?
    sounds confusing...what does it mean?

  3. #3
    Join Date
    Mar 2004
    Location
    SE Michigan
    Posts
    17,821
    100k seems a bit much for atlanta, however he does have to move quite a bit of air haveing a 3.5 ton a/c.
    "Politicians are the lowest form of life on Earth. Liberal Democrats are the lowest form of politician"

    - General George S. Patton

  4. #4
    Join Date
    Jul 2005
    Location
    FLORIDA
    Posts
    1,163
    sounds like you got money
    once you think you've seen it all
    (THINK AGAIN)
    I would rather work for free than be look upon as a thief!!!!!

  5. #5
    Join Date
    May 2000
    Location
    Indianapolis, IN, USA
    Posts
    33,902
    He said he had to go with the 100,000 BTU furnace to get the airflow needed for the heat pump, not for the heat load. Does this sound right?
    No it isn't. There is an 80,000 BTU furnace with enough blower for the 3.5 ton heat pump.

    Is this 1700 sq ft per floor or for both floors? If 3 ton did the job in the past why go bigger? Or didn't it?

  6. #6
    Join Date
    Oct 2005
    Location
    N Metro Atlanta GA
    Posts
    70

    Thanks for the input

    Jacob - don't know what it means exactly, but that was his answer I thought 100K was too big. He did all calculations, sizing and proposal preparation on his laptop.

    Cool - I think that is what he was saying.

    dirtyboy - nope, don't have the money to throw at this wastefully.

    Bald - 1700 sq ft is both floors, each is 857.
    The only thing I remember about his load calc was 95* outside & (I think) 75* inside design temp, 2.5 tons for first floor on slab, 1.5 tons for second floor.
    I'm glad to hear that there is an 80K BTU furnace with enough blower. I want to save as much as I can.
    The 3 ton would run for 1.5 hr or more set at 79 with outside 92-95. I don't think it could have pulled any cooler. But he never asked how well the current setup worked.

  7. #7
    Join Date
    Apr 2004
    Location
    Bartlett, IL
    Posts
    6,619
    Boy 'o' Boy, dude does a heat load and still gets slammed....what next?

  8. #8
    Join Date
    May 2000
    Location
    Indianapolis, IN, USA
    Posts
    33,902
    1700 sq ft total, 3.5 ton sounds like a lot of cooling. No insulation? Lots of windows?

    He may have done a load calc but still seems fishy. 100K and 3.5 ton for only 1700 sq ft and a 2 story to boot so only 857 sq ft of attic. I'm trying to understand this.

    We may build our houses that much tighter up here the reason we can get by with lots less capacity. I saw a couple of 2600+ sq ft homes get done this summer with 2.5 ton total. No complaints, the salesman ran his inspection on one of them on a very steamy day. 70 inside.

  9. #9
    Join Date
    Aug 2004
    Location
    Tyler TX
    Posts
    676
    In atlanta you will not get much use out of the furnace. As mentioned earlier there is an 80 available and would ask why that furnace would not do. Also mentioned earlier if a 3 ton had done the job why now do you need to upsize? There may be a good reason for this but keep in mind an oversized AC will remove less moisture from the air and will require lower set points to achieve the same comfort level.

    The company that gave you the quote may be right in there suggestions but ask a few questions to be sure
    HVAC Contractor, Tyler Texas.

  10. #10
    Join Date
    Jul 2005
    Location
    FLORIDA
    Posts
    1,163
    OK here goes this from memory i live in Fla. mind you

    10. kW heat strip is what i would use in a 3 to 3 1/2 ton heat pump ton unit i would look at the house and see how old it was and take a peak in the attic to see the insulation now i would measure the house and go with 500 sq. ft per ton depending on
    windows if they were those jealousy windows i would go up a half a ton to make up for it that's what's in the j manual and it works now if is a newer home or has had insulation added then i would go down a half a ton and make sure they went with a higher efficient unit that will pump more of the load and run
    longer to pull out the humidity
    once you think you've seen it all
    (THINK AGAIN)
    I would rather work for free than be look upon as a thief!!!!!

  11. #11
    Originally posted by BaldLoonie
    He may have done a load calc but still seems fishy. 100K and 3.5 ton for only 1700 sq ft and a 2 story to boot so only 857 sq ft of attic. I'm trying to understand this.
    I have a blueprint right now where the home is 1900 Sq Ft and he told the last guy he wanted a 115K 93% furnace!

    You know the type, the bigger the better!

  12. #12
    Join Date
    Nov 2000
    Location
    Waco, Texas, USA
    Posts
    6,153
    If you want to save money forget about the gas furnace and just go with the heat pump. No need for both. What kind of air filtering system will you have to protect your investment?
    "And remember my sentimental friend......that a heart is not judged by how much you love, but by how much you are loved by others" - Wizard of Oz.

  13. #13
    Join Date
    Oct 2005
    Location
    N Metro Atlanta GA
    Posts
    70

    This may be to much info

    Here are MY measurements for the first floor. Walls are area after subtracting windows & doors.

    NE Wall 52.4 sq.ft.
    ...Window 17.6 sq.ft.
    ...Window (2) 17.6 sq.ft.
    ...Window (3) 17.6 sq.ft.
    ...Window (4) 17.6 sq.ft.
    ...Window (5) 7 sq.ft.
    ...Window (6) 7 sq.ft.
    ...Door 40.5 sq.ft.
    SE Wall 177.3 sq.ft.
    SW Wall 206 sq.ft.
    ...Window 17.6 sq.ft.
    ...Window (2) 17.6 sq.ft.
    ...Window (3) 10 sq.ft.
    ...Window (4) 10 sq.ft.
    ...Window (5) 10.5 sq.ft.
    ...Glassdoor 37.6 sq.ft. (Double pane)
    NW Wall 141.5 sq.ft.
    ...Window 5.3 sq.ft.
    ...Door 30.5 sq.ft.

    Windows are all, unfortunately, single pane wood frame.

    I REALLY appreciate the input!

    [edited] Oh yeah, there heavy shade to the south and west. The house is in full sunlight about 9:30 - 1:30

    [Edited by i g norant on 10-21-2005 at 11:24 PM]

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