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  1. #14
    Join Date
    Nov 2004
    SW FL
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    Question $ / kw-Hr + Building Envelope

    Originally posted by tbsunflower

    1st story 1500 sq ft
    2nd story 1200 sq ft
    CA - N. of Sacramento
    House Orientation
    Effective use of Porches and Overhangs

    Windows - Sq. foot each side
    Windows Tinting


    Duct design and material
    Equipment placement

    Square Footage
    Wall Height

    Natural Shading
    Tightness - Infiltration
    Roof Color

    T-stat setting
    Lighting Efficiency

    ___ covers some of the factors
    in A/C sizing and equipment selection ...

    4.5 Tons may be sufficient
    depending on the combination of the above factors.

    Consideration of 16 SEER
    may be realistic for a few
    IF electric rates are Very High in their area.

    Length of Stay anticipated in Home
    > 20 years

    N. CAL $/ Kw-Hr = $0.____ ?

    Need additional specific assistance
    racingdan11 at
    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

  2. #15
    Join Date
    Jun 2005
    Near Chicago, IL
    Post Likes
    Originally posted by nathan9999
    I would strongly encourage you to buy the HVAC-Calc program featured on this site and spend a few hours performing a load calculation.

    I live in Bakersfield, CA which is very similar to Sacramento's weather. My 3139 new home comes in at 4.5 tons based on the calculation. The original plan called for 6 tons. I'll be installing a 5 ton unit.

    You might be surprised at the results of a thorough heat gain calculation. You might also surprised how many contractors profess not to believe in the calculation, or at least refuse to perform a calculation.
    The HVAC Calc program is good, and it works, but you had better pay attention to the "sensible" and "latent" loads, not what the program tells you for "tons".

    A 5 ton condenser is not going to give you 60k btu of sensible cooling capacity.
    Proper Prior Planning Prevents Piss Poor Performance

    "There is hardly anything in the world that some man cannot make a little worse and sell a little cheaper, and the people who consider price only are this man's lawful prey. It's unwise to pay too little.
    When you pay too much, you lose a little money -- that is all. When you pay too little, you may lose everything, because the thing you bought was incapable of doing the thing it was bought to do.

    The common law of business balance prohibits paying a little and getting a lot -- it can't be done. If you deal with the lowest bidder, it is well to add something for the risk you run. And if you do that, you will have enough to pay for something better."

    John Ruskin

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