Connecticut Replacement of system: Variable vs Single Speed

Discussion in 'General Discussions' started by ToolmanJohn, Jan 25, 2020.

  1. ToolmanJohn

    ToolmanJohn New Member

    My system was installed in 2008. 2.5T split closed loop non-pressurized, raised ranch, Connecticut. Hydron Module H030C10 Single stage compressor, Lennox CBX26UH-030 Air Handler Evaporator unit, and loop pump (B&D QT flow center).

    Raised Ranch 1400 sq ft finished space (includes heated finished basement area of 400 sq ft).

    Wondering what percentage savings in power consumption a variable speed system would be when i have to replace the current one. My guess would be sometime around 2032, right about when I am thinking of retiring.

    10%, 20%, 30% more? Does it make sense for my small 2.5T system? I currently see that the current split systems are sized at one ton intervals, 2T 3T etc, which would mean a 3T system, but it likely wouldn't need to run at 100%, which would be a problem if it did, as my well depth (closed loop) is at 364 feet, size for 2.5T.
     
  2. SShaw

    SShaw Member

    Knowledgeable dealers will have access to software that can generate a report of the operating costs for various systems. You can also do an analysis yourself with online tools like LoopLink RLC.

    For my house the projected savings was 20% for a 4T variable speed vs a 4T two-stage. The additional cost for variable speed was about $4K before the tax credit.
     
  3. ToolmanJohn

    ToolmanJohn New Member

    Ok thanks, good to know about the calculator.
     
  4. docjenser

    docjenser Well-Known Member Industry Professional Forum Leader

    Gentlemen,

    the size of the loopfield is determined by the amount of heat extracted. A 4 ton unit would roughly extract the same amount if heat from the loopfield with the exception s to cover more of the peak, which is about 1-2% of the load, normally. Your leepfield would not even know it, and if so, it would drop by a couple degrees for a few days. Now what?

    We just replaced a single stage 3 ton with a variable speed 4 ton, including variable speed pump. The variable speed run between 0.8 and 3 ton capacity most of the time, and only a few hours a year it covers the peak and runs above 3 ton, putting some more stress on the loop field, so the temperature drops a couple degrees during a zero degree night.

    I have attached the power consumption of a 5200 sqf leaky farmhouse in Weatherfield NY, at elevation. Absolutely coldest spot. Lowest temp this year was -9F.
    Here is the system.
    http://welserver.com/WEL0447/

    So we exchanged a 6 ton Heatcontroller (same as Climatemaster 27) dual stage with a variable speed 5 ton 7 series and a single variable speed loop field pump.
    The 7 series was not only over 40% more efficient (energy use was 58.7% compared to the 6 ton, weather normalized) but also had a higher capacity, dipping lesser into supplement heat.
    It showed an impressive leap in performance.
     

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