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  1. #1
    Join Date
    Jun 2005
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    2
    We have had several quotes from different HVAC contractors in our area. I have 3 separate proposals all saying we needed a 3 ton system. I then called the person that installed the furnace and he said, we need a 3.5 ton unit. He was a trane dealer and recently did the install of the furnace on the home. I also had another Trane dealer come here and spent an hour measuring our home and determined we needed a 2.5 ton unit. I'm confused that there would be such a discrepancy and don't have a clue what to do. I have tried to get some referrals from people but being new to the area, we don't really know anyone. This is a new 2000 square foot home in Beaverton, Oregon.


    1. What can happen if we don't install the right size unit?
    2. Would it make sense to just install a 3 ton unit?

  2. #2
    Join Date
    Nov 2004
    Location
    SW FL
    Posts
    6,294

    Lightbulb Size = 3-ton

    Originally posted by martier1
    We have had several quotes from different HVAC contractors in our area. I have 3 separate proposals all saying we needed a 3 ton system.

    I have tried to get some referrals from people but being new to the area, we don't really know anyone. This is a new 2000 square foot home in Beaverton, Oregon.

    2. Would it make sense to just install a 3 ton unit?
    Yes, 3-ton surely seems Appropriate for a BEAVERTON 2,000 S.F. residence with < 350 Square Feet of glass.

    Do you have a total of < 350 Sq. feet of glass?

    IF > 350 sq. feet (including sliding glass doors), please provide square footage of glass and degree of tinting ( S.H.G.C.) on each side of the house.
    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

  3. #3
    Join Date
    May 2002
    Location
    Colorado
    Posts
    697
    Your area (Portland, OR) is neither very hot nor very humid. I doubt that a new home there with 2,000 square feet of conditioned space would need more than 2 tons unless it is poorly constructed/sealed/insulated or has an unusual amount of glass on the east or west sides.

    Why not go with the Trane dealer who spend an hour measuring your home? If he will do that, don't you suppose he will take whatever time is necessary to install your system properly?

    If a system is too large (assuming proper installation in the first place) it will cycle on and off too much. This leads to discomfort and wears out the system sooner. And when you have humid weather, it won't remove the humidity as well as a smaller system that has longer run times.

    Furthermore, it is essential that the duct system be large enough for the air conditioner and that the blower on the furnace be sized correctly for it. Sometimes it may be best to go up or down a 1/2 ton or so to get the air flow right. If your furnace has a 3-ton blower on it, a 2.5 ton condensing unit should work just fine.

    I've yet to see a residential system that is undersized. If a system won't keep the house cool, it is always because of faulty installation or improper charge.

    Whatever you get MAKE SURE IT HAS A THERMOSTATIC EXPANSION VALVE (TXV). Don't let anyone talk you out of one.

  4. #4
    Join Date
    Jun 2005
    Posts
    2
    The front of the house faces west and the lot is small so many of the windows will not have direct sunlight. There are over 15 windows. All windows are low E untinted with very few facing south.

  5. #5
    Join Date
    Nov 2004
    Location
    SW FL
    Posts
    6,294

    Beaverton OR Climate

    Originally posted by Panama
    I doubt that a new home there with 2,000 square feet of conditioned space would need more than 2 tons. ...

    ... go up or down a 1/2 ton or so to get the air flow right. If your furnace has a 3-ton blower on it, a 2.5 ton condensing unit should work just fine.

    http://www.weather.com/activities/ev...ttomnav_sports

    With such a mild summer and only 15 windows (say, < 290 Square feet of total glass area), a 2.5 ton with 3-ton blower will work > 96% of the time.

    Try pricing TRANE models ...
    1. 4TTR 2030 with 4TEE 3F037 for minimum cost
    +++++++++++++++ durable, reliable equipment

    2. 4TTX 6036 with 4TEE 3F040 for less energy cost

    However, your $ energy cost for A/C will likely be < $400 for the whole cooling season. ... very limited chance of recovering cost in a reasonable period based on XL16i pricier initial system cost.
    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

  6. #6
    Join Date
    May 2004
    Posts
    12,028
    Originally posted by martier1
    We have gotten several quotes priced around the same for installation. Only a few hundred dollars separate these quotes.

    For the same amount:

    Goodman 13 seer 3 Ton
    Amana 12 seer 3 Ton
    Trane 10 seer 3.5 Ton
    Payne 12 seer 3 Ton

    If the price is the same, which unit would be the best? With very little knowledge, it would seem that the 13 seer would be the best due to it's efficiency.

    Felt most comfortable with the Trane guy that spent an hour measuring our house and said we need a 2.5 ton, 12 Seer. However, his cost was almost $700 more than the models listed above.

    We plan to be in house no more than 5 years.

  7. #7
    Join Date
    May 2004
    Posts
    12,028
    Originally posted by splitbolt
    I'm going to put it to you this way: my own personal experience is that I am pulling dead Goodman and Payne systems out all of the time, and I never replace them with the same brand. When I pull out a dead Trane, I'm almost always putting another new Trane back in.

    I use to install Amana's exclusively earlier in my career, and I like them, but I've relocated since to an area Amana is hardly seen, so I can't comment on logitivity there.

    People will line up to tell you it matters highly on the quality of the install, which is entirely true, but even then I don't believe all units are equal.

    I'll shut up now before I get lambasted.


  8. #8
    Join Date
    May 2004
    Posts
    12,028
    Originally posted by contactor
    High SEERS are better. A good installer is the best.

  9. #9
    Join Date
    May 2004
    Posts
    12,028
    Originally posted by Edmund Forsthe
    pure personal preference if they are priced the same pick which one appeals to your sense of aestetics, and hope you get a good installer

  10. #10
    Join Date
    Mar 2004
    Posts
    1,042
    Yep. The guy that spent an hour measuring is the one that took the time to do the real calculations for the correct system size. As usual, the one who measures and calculates using Manual J ends up quoting the smallest tonnage system. He's the winner, any day of the week. Everyone else just guesstimated.

    The reason he's more expensive is because 1) Trane equipment is more expensive than the other brands quoted, 2) Trane 12-seer costs more than Trane 10-seer, and 3) he's the one that's going to do the best installation work and provide the best results. If the $700 difference worries you that much, ask him what his price would be for a 10-seer system instead of the 12.



    [Edited by wyounger on 06-03-2005 at 02:29 PM]

  11. #11
    Join Date
    May 2002
    Location
    Colorado
    Posts
    697
    Which of them are going to include a TXV?

    Which of them are going to include a liquid line filter/drier?

    Which of them are going to purge the system with nitrogen while brazing?

    Which of them are going to use high quality brazing rods?

    Which of them are going to run the line set so the liquid line doesn't touch the house?

    Which of them are going to spend the time to properly evacuate the system?

    Which of them are going to leak test the system?

    Which of them are going to adjust the refrigerant properly and not just by pressures?

    Which one of them are going to measure the air flow and temperature drop to ensure they are correct?













  12. #12
    Join Date
    Jun 2005
    Location
    montreal, canada
    Posts
    9
    pretty simple 700 feet sq for 1 ton, this is how to do it ,i don t know why people broke her head to know what capacity !

  13. #13
    Join Date
    Nov 2004
    Location
    SW FL
    Posts
    6,294

    Thumbs down Rule of

    Originally posted by eric fillion
    pretty simple 700 feet sq for 1 ton, this is how to do it ... !
    700, Right, ... somewhere between 340 to 900 Sq. Ft per ton, Of Course, depENDing on where you keep yourself.
    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

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