# Connecticut Replacement of system: Variable vs Single Speed

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

1. ### ToolmanJohnNew 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. ### SShawMember

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. ### ToolmanJohnNew Member

Ok thanks, good to know about the calculator.

4. ### docjenserWell-Known MemberIndustry ProfessionalForum 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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• ###### CM27 versus 7 series copy.jpg
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