Heat Loss

Discussion in 'General Discussions' started by johncomyn, Aug 19, 2008.

  1. johncomyn

    johncomyn New Member

    Hi, I new here and am looking at installing a ground loop system.

    The contarctor has quoted me a Climate Master 4 ton unit.

    I tried to do a heat loss on this website and came up with between 60,000btuh to 70,000btuh heat loss.

    Home Heat Loss Calculator

    According to the Climate Master website the full load Btuh is 37500. I'm thinking the unit is too small.

    Or the link I supplied is giving me way incorrect info.

    Maybe I'm not understanding how they decide what size unit to use.

    What size unit do you guys think I'd need at 60,00btuh?

    Thanks for any help.

  2. Ona

    Ona Member


    Did your contractor do a manual J calculation? Did he/she share it with you? This is the first step in sizing a system. It is actually what the website that you referred us to is based on.

    It is not unusual for a geo system to not fully cover the heat loss because over sizing the system will make your home humid in the summertime. I believe that some geo systems recommend undersizing the heat load to an amount equal to ~15% of use. Meaning, during a typical year in your climate, the electric coil backup may run ~15% of the time.

    I am not a contractor, just someone who has done some research and interviewed many contractors before having my system installed (which is still in process).

    Good Luck!
  3. johncomyn

    johncomyn New Member

    Thanks for the reply.

    Not sure what his calculations are. I will try to get the information from him.

    From my estimates on the website I mentioned, I think the 5 ton would be more appropriate. What do you think?

    What I have not calculated for is heat gains due to southern exposure. We have quite a few windows for sun to shine in.


  4. Ona

    Ona Member

    Since I am not a professional, I don't really want to give too much advice. But my gut tells me that you want to go smaller. Maybe someone else from the forum with professional experience will have some better insight than me.

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