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  1. #1
    Join Date
    Mar 2008
    Posts
    1

    Default New Central HVAC System Questions

    I am installing a new HVAC system in my home and have three bids from Rheem, Amana and Carrier contractors. The home has approximately 2,000 s.f. and I am going with 16-17 SEER A/C, 95% Furnace ratings. One of the contractors is suggesting going with 5 ton system and the others are at 4 tons. Is a 5 ton system overkill? Is Amana a good product? I am hoping to get responses. Thanks.

  2. #2
    Join Date
    Aug 2007
    Posts
    443

    Default Re: New Central HVAC System Questions

    Did the estimators include a HEAT GAIN CALCULATION in their estimate?

    Ask them if they did a Manual J calculation and a Manual D calculation.

    The only accurate way to determine how many tons of cooling you need if for the contractor to do a HGC, known as a Manual J calculation.

    The HGC takes into account factors that can make a BIG difference in YOUR house as compared to any other house:

    1) Is your location in an area with cold summers.
    2) Are you located in a very hot, humid part of the country.
    3) How much insulation is in the exterior walls & attic.
    4) How much westerly & southern exposure does your house have---are there any trees shading the house.
    5) How much window glass is there & how much of it faces south and/or west.

    If you Google "heat gain calculation" you can get a number of free calculations that will give you some idea with all these factors put into the calculation program.

    The site below is a start, but is rudimentary.

    The free slant/fin site is much more comprehensive---I believe it includes HEAT GAIN as well as HEAT LOSS factors.

    There is a general rule of thumb that says to divide the square footage of the house by 650 to get the number of tons needed (one ton = 12,000 btu/hr cooling)---but that is very simplified & doesn't take into account the variables mentioned above.

    The contractor should also do a Manual D calculation which properly sizes the heating/cooling ducting to get adequate conditioned air to & from the registers of each room without causing air noise.

    The SEER and Heating Efficiency ratings sound excellent.

    I don't know enough about Amana to comment on their quality.

    http://www.heatload.com
    http://www.slantfin.com/heat-loss-software.html
    http://www.vonwentzel.net/HVAC/HVAC-...ors/index.html
    Last edited by JacktheShack; 03-28-2008 at 10:35 AM.

  3. #3
    Join Date
    Jun 2007
    Location
    tn
    Posts
    17

    Default Re: New Central HVAC System Questions

    see if you can get a quote on a goodman

  4. #4
    Join Date
    Aug 2007
    Location
    The Great White North
    Posts
    4,045

    Default Re: New Central HVAC System Questions

    I agree with JacktheShack.

    There needs to be a correct heat gain/loss calculation done to determine what's required.

    There maybe an issue where you may fall in between a 4 or 5 ton unit and the one contractor is moving you up to the higher .... it probably costs a little more.

    If you do fall into just below the 5 ton you may be better off with the 4 ton ... depends.

  5. #5
    Join Date
    May 2008
    Location
    Derby City
    Posts
    42

    Default Re: New Central HVAC System Questions

    Jack the Shack told you what you need to know. Follow his recommendations.

  6. #6

    Default Re: New Central HVAC System Questions

    Jack is right -there is another part of the evaluation that can be done.The insulation in the home can be tightend up and or add more. Have a blower door or thermal image done on the home.These technologies can save you some money on the tonnage.If you know where the heat loss is and repair it ,it will save you money in the long run.outlets and attic doors are great areas of heat loss and gain. Just a thought when you do a load calc the system and insulation is assumed.but if you can see that the windows and walls are insulated for sure there will be no guessing.

  7. #7
    Join Date
    May 2008
    Posts
    13

    Default Re: New Central HVAC System Questions

    All of the above are correct, there is no magic out of my price book-one size fits all- size. However, I will go out on a limb here and say if your 2000 ft home requires 5 tons of AC there may very well be other issues you should address that could save you money......like that wind blowing through that hole in your wall, or that missing window.

    As far as brand goes, I would check and see how long the distributer(not dealer) for that brand has been in your area. We have no control over manufacturer quality, but having a York, for example, when the nearest York distributer is 400 miles away sucks when its 105 on Saturday.
    There are quality products at every price level in the market. Having said that, there is something to be said sometimes about getting what you pay for, and hiring a Factory Authorized Dealer for that product......I am not here to endorse any brand, but I will say beware of brands that sell to any Tom,Dick, and Harry that comes along. Go for a factory authorized dealer.....truth be told, I can get alot more done as a FAD if something goes wrong than most can. May not matter now, but any product can be a lemon, and it can sure matter having someone that can and will do whatever it takes to fix your problem, and someone who moves an amount of equipment that the manufacturer will do what they need to in order to make that DEALER happy....Factory reps do not treat all dealers the same.
    Get a Brand that has had a distributer in your town for a long time, and buy that brand from a dealer that has been selling that brand, and is a FAD.

  8. #8

    Default Re: New Central HVAC System Questions

    Help
    i need help

    THIS IS FOR A NEW HOME NEW CONSTRUCTION
    i need 2 five ton units an 1 two ton unit
    one hvac company nis recomending carrier the other is recomending magic aire handler and luxaire condenser
    i need a high seer unit
    what should i do or can you recomend a better unit w a better seer

    peter

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